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Purpose: To assess the impact of 3 months of orthokeratology (ortho-k) contact lenses (CLs) for myopia correction on the corneoscleral profile, as changes in scleral geometry could serve as indirect evidence of alteration in the corneal biomechanical properties. Methods: Twenty subjects (40 eyes) were recruited to wear ortho-k lenses overnight; however, after discontinuation (two CL fractures, one under-correction and two non-serious adverse events), 16 subjects (31 eyes) finished a 3-month follow-up. Corneoscleral topographies were acquired using the Eye Surface Profiler (ESP) system before and after 3 months of lens wear. Steep (SimKs) and flat (SimKf) simulated keratometry and scleral sagittal height measurements for 13-, 14- and 15-mm chord lengths were automatically calculated by the ESP software. Additionally, sagittal height and slope were calculated in polar format from 21 radii (0–10 mm from the corneal apex) at 12 angles (0–330°). Linear mixed models were fitted to determine the differences between visits. Results: SimKs and SimKf were increased significantly (p ≤ 0.02). The sagittal height in polar format increased significantly (p = 0.046) at a radius of 2.5 mm for 150°, 180°, 210° and 240° orientations and at a radius of 3.0 mm for 210°. Additionally, the slope in polar format significantly decreased (p ≤ 0.04) at radii ranges of 0.0–0.5, 0.5–1.0 and 1.0–1.5 mm for multiple angles and at a radii range of 5.0–5.5 mm for 90°. It also increased significantly (p ≤ 0.045) at a radii range of 1.5–2.0 mm for 30° and at radii ranges of 2.0–2.5, 2.5–3.0 and 3.0–3.5 mm for multiple angles. No significant changes were found for any parameter measured from the scleral area. Conclusions: Three months of overnight ortho-k lens wear changed the central and mid-peripheral corneal geometry as expected, maintaining the peripheral cornea and the surrounding sclera stability.

The aim was to evaluate the safety, efficacy, and visual performance of an orthokeratology lens with an increased compression factor (ICF) of 1.25 D in a 3-month follow-up. Thirty-six myopic patients (5 males and 31 females; 24.2 ± 5.8 years) were fitted with Alexa AR (Tiedra Farmacéutica S.L., Madrid, Spain) contact lenses (CLs) and twenty participants finished the follow-up. Visual acuity (VA), subjective refraction, primary spherical and primary coma aberrations, keratometry, central pachymetry, and ocular surface evaluation were performed at baseline and after 1 night, 1 week, 1 month, and 3 months of CL wear. The differences among visits were analyzed using a repeated-measures analysis of variance or the Friedman test. The spherical equivalent decreased (p ≤ 0.005), and the uncorrected VA improved (p < 0.001) until the first week. Corneal and ocular aberrations showed a significant increase (p ≤ 0.02). A significant decrease (p < 0.001) was found for keratometry values. No significant changes were observed in either central pachymetry or ocular surface parameters among study visits. In conclusion, an orthokeratology CL with an ICF of 1.25 D provides good safety, efficacy, and visual performance in a 3-month follow-up. Seven days of orthokeratology wear are enough to achieve the full myopic compensation, resulting in satisfactory VA.

Received 11 October 2023, Revised 21 February 2024, Accepted 1 March 2024, Available online 11 March 2024, Version of Record 16 May 2024. 2023 Acuerdos transformativos CRUE-CSIC, Background: To assess accommodation and spherical aberration changes during one year of orthokeratology lens wear and one month after lens cessation. Methods: A prospective, randomized, longitudinal study was conducted on forty-seven young healthy subjects at the Optometry Clinic of the Complutense University of Madrid (Spain). Non-cycloplegic refraction, high and low uncorrected visual acuity, high and low best corrected visual acuity, accommodative lag, horizontal near phoria, corneal topography, and high-order aberrations were performed at baseline, 1-day, 1-week, 1-, 6- and 12-months of lens wear and after one month of wash out period. p < 0.05 was considered as statistically significant. Results: Spherical equivalent refraction (SE) was -3.23 ± 1.57D at baseline and -0.36 ± 0.64D after 12-months of lens wear, while accommodative lag changed from 0.53 ± 0.39D to 0.15 ± 0.29D after one year of lens wear. No significant differences were found when comparing SE at baseline and after one month of lens cessation (p > 0.05). A high correlation was found between the accommodative lag at baseline and after 12 M of lens wear. 22 out of 25 subjects with exophoria at baseline showed a significant reduction in the deviation at 12-months (p < 0.05). Total spherical aberration increased during all visits due to the lens wear (p < 0.05) although internal spherical aberration showed a significant decrease for 1-week, 1-month and 12-month visits (p < 0,05). Conclusion: Orthokeratology lenses may change the accommodative response of the patient as a reduction on accommodative lag on exophoric patients and an overall increase on the internal spherical aberrations was found during treatment but return to nearly baseline values when cessation., Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, inpress, APC financiada por la UCM

Producción Científica, The aim was to evaluate the safety, efficacy, and visual performance of an orthokeratology lens with an increased compression factor (ICF) of 1.25 D in a 3-month follow-up. Thirty-six myopic patients (5 males and 31 females; 24.2 ± 5.8 years) were fitted with Alexa AR (Tiedra Farmacéutica S.L., Madrid, Spain) contact lenses (CLs) and twenty participants finished the follow-up. Visual acuity (VA), subjective refraction, primary spherical and primary coma aberrations, keratometry, central pachymetry, and ocular surface evaluation were performed at baseline and after 1 night, 1 week, 1 month, and 3 months of CL wear. The differences among visits were analyzed using a repeated-measures analysis of variance or the Friedman test. The spherical equivalent decreased (p ≤ 0.005), and the uncorrected VA improved (p < 0.001) until the first week. Corneal and ocular aberrations showed a significant increase (p ≤ 0.02). A significant decrease (p < 0.001) was found for keratometry values. No significant changes were observed in either central pachymetry or ocular surface parameters among study visits. In conclusion, an orthokeratology CL with an ICF of 1.25 D provides good safety, efficacy, and visual performance in a 3-month follow-up. Seven days of orthokeratology wear are enough to achieve the full myopic compensation, resulting in satisfactory VA., Universidad de Alicante y Tiedra Farmacéutica S.L - ( project TIEDRA1-21A), Comunidad Valenciana, Centro Internacional para la Investigación del Envejecimiento (ICAR) - (project PRESBYSIM), Unión Europea—NextGenerationEU - (grant UNI/551/2021; CONVREC-2021-18).

Purpose: To review the rebound effect after cessation of different myopia control treatments. Methods: A systematic review that included full-length randomised controlled studies (RCTs), as well as post-hoc analyses of RCTs reporting new findings on myopia control treatments rebound effect in two databases, PubMed and Web of Science, was performed according to the PRISMA statement. The search period was between 15 June 2023 and 30 June 2023. The Cochrane risk of bias tool was used to analyse the quality of the selected studies. Results: A total of 11 studies were included in this systematic review. Unifying the rebound effects of all myopia control treatments, the mean rebound effect for axial length (AL) and spherical equivalent refraction (SER) were 0.10 ± 0.07 mm [−0.02 to 0.22] and −0.27 ± 0.2 D [−0.71 to −0.03] after 10.2 ± 7.4 months of washout, respectively. In addition, spectacles with highly aspherical lenslets or defocus incorporated multiple segments technology, soft multifocal contact lenses and orthokeratology showed lower rebound effects compared with atropine and low-level light therapy, with a mean rebound effect for AL and SER of 0.04 ± 0.04 mm [0 to 0.08] and −0.13 ± 0.07 D [−0.05 to −0.2], respectively. Conclusions: It appears that the different treatments for myopia control produce a rebound effect after their cessation. Specifically, optical treatments seem to produce less rebound effect than pharmacological or light therapies. However, more studies are required to confirm these results.

Purpose. To compare the ocular surface symptoms and signs in an adult population of silicone-hydrogel (Si-Hy) contact lens (CL) wearers with another modality of CL wear, overnight orthokeratology (OK). Materials and Methods. This was a prospective and comparative study in which 31 myopic subjects were fitted with the same Si-Hy CL and 23 underwent OK treatment for 3 months. Dry eye questionnaire (DEQ) was filled in at the beginning of the study and then after 15 days, 1 month, and 3 months using each CL modality. The tear quality was evaluated with noninvasive tear break-up time. Tear production was measured with Schirmer test. Tear samples were collected with Schirmer strips being frozen to analyze the dinucleotide diadenosine tetraphosphate (Ap4A) concentration with High-Performance Liquid Chromatography (HPLC). Results. After refitting with ortho-k, a reduction in discomfort and dryness symptoms at the end of the day (, ) was observed. No significant changes were observed in Ap4A concentration in any group. Bulbar redness, limbal redness, and conjunctival staining increased significantly in the Si-Hy group (, Kruskal–Wallis test). Conclusion. Discomfort and dryness symptoms at the end of the day are lower in the OK CL group than in the Si-Hy CL group., Xunta de Galicia, Redes Temáticas de Investigación Cooperativa en Salud (España), Fundación para la Ciencia y la Tecnología (Portugal), Depto. de Optometría y Visión, Unidad Docente de Bioquímica y Biología Molecular, Fac. de Óptica y Optometría, TRUE, pub

Background To evaluate short-term (3 months) and long-term (3 years) accommodative changes produced by overnight orthokeratology (OK). Methods A prospective, longitudinal study on young adult subjects with low to moderate myopia was carried out. A total of 93 patients took part in the study. Out of these, 72 were enrolled into the short-term follow-up: 21 were on a control group, 26 on a Paragon CRT contact lenses group, and 25 on a Seefree contact lenses group. The other 21 patients were old CRT wearers on long-term follow-up. Accommodative function was assessed by means of negative and positive relative accommodation (NRA / PRA), monocular accommodative amplitude (MAA), accommodative lag, and monocular accommodative facility (MAF). These values were compared among the three short-term groups at the follow-up visit. The long- and short-term follow-up data was compared among the CRT groups. Results Subjective accommodative results did not suffer any statistically significant changes in any of the accommodative tests for any of the short-term groups when compared to baseline. There were no statistically significant differences between the three short-term groups at the follow-up visit. When comparing the short- and long-term groups, only the NRA showed a significant difference (p = 0.0006) among all the accommodation tests. Conclusions OK does not induce changes in the ocular accommodative function for either short-term or long-term periods., Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Received 18 July 2015 ; Received in revised form 6 April 2016 ; Accepted 6 April 2016, Objective: To evaluate the differences between goblet cell density (GCD) and symptomatology after one month of orthokeratology lens wear. Methods: A pilot, short-term study was conducted. Twenty-two subjects (29.7. ±. 7.0 years old) participated voluntarily in the study. Subjects were divided into two groups: habitual silicone hydrogel contact lens wearers (SiHCLW) and new contact lens wearers (NCLW). Schirmer test, tear break up time (TBUT), Ocular Surface Disease Index (OSDI) questionnaire and conjunctival impression cytology. GCD, mucin cloud height (MCH) and cell layer thickness (CLT) were measured. All measurements were performed before orthokeratology fitting and one month after fitting to assess the evolution of the changes throughout this time. Results: No differences in tear volume and TBUT between groups were found (p>0.05). However, the OSDI score was statistically better after one month of orthokeratology lens wear than the baseline for the SiHCLW group (p=0.03). Regarding the goblet cell analysis, no differences were found in CLT and MCH from the baseline visit to the one month visit for the SiHCLW compared with NCLW groups (p>0.05). At baseline, the GCD in the SiHCLW group were statistically lower than NCLW group (p<0.001). There was a significant increase in GCD after orthokeratology fitting from 121±140cell/mm2 to 254±130cell/mm2 (p<0.001) in the SiHCLW group. Conclusion: Orthokeratology improves the dry eye subject symptoms and GCD after one month of wearing in SiHCLW. These results suggest that orthokeratology could be considered a good alternative for silicone hydrogel contact lens discomfort and dryness. © 2016 British Contact Lens Association., Universidad Complutense de Madrid, RETICS (Redes Temáticas de Investigación Cooperativa en Salud), Depto. de Optometría y Visión, Unidad Docente de Bioquímica y Biología Molecular, Fac. de Óptica y Optometría, TRUE, pub

Purpose To study topographic epithelial and total corneal thickness changes in myopic subjects undergoing successful orthokeratology treatment in connection with the objective assessment of contact lens decentration. Methods A prospective-observational and non-randomized study in 32 Caucasian myopic eyes undergoing Ortho-k for 3 months. Total, epithelial, and stromal thicknesses were studied before and after Ortho-k treatment, using optical coherence tomography with anterior segment application software. Central, paracentral, and mid-peripheral values are taken along 8 semi-meridians.

Clinical relevance: The changes in various biomechanical and tomographic characteristics of the cornea associated with orthokeratology may allow us to identify potential mid- and long-term structural alterations, resulting in a better understanding of the governing mechanisms of this procedure and in its optimisation. Background: The study aimed at describing short and mid-term changes in CORVIS ST® parameters and indices in orthokeratology (ortho-k), and their diurnal variations. Methods: A prospective observational study was designed in which several CORVIS ST® parameters of 75 new adult participants successfully fitted with overnight ortho-k Seefree® (Conóptica – Hecht Contactlinsen) contact lenses were explored. Measurements were conducted in baseline (BL) conditions and in the morning and evening at the one-night (1 NM/1NT), one-week (1WM/1 WT) and 3-month (3 MM/3MT) follow-up visits. Results: Statistically significant differences were found in DARatio_2 mm, IntRad, ARTh, CBI and TBI following overnight ortho-k, when compared with BL values, with most values reaching stability at 1WM or reverting to BL values at 3 MM. The ARTh and CBI parameters showed some of the most significant temporal variations (both p < 0.001), probably reflecting the encountered differences in central corneal thickness between BL and 1WM (p = 0.010) and between BL and 3 MM (p = 0.016). In general, corneal rigidity was higher in the morning at all follow-up visits, and decreased during the day. No statistically significant changes in adjusted intraocular pressure values were found. Conclusion: Ortho-k in adults may be considered a safe procedure in terms of short and mid-term changes in CORVIS ST® parameters. The observed alterations in most of the parameters provided by the Corvis ST® probably responded to the well-described changes in corneal pachymetry and tomography, rather than to actual alterations in corneal rigidity.

Clinical relevance: The analysis of the changes in various biomechanical and tomographic characteristics of the cornea associated with orthokeratology may allow to identify potential mid- and long-term structural alterations, resulting in a better understanding of the governing mechanisms of this procedure and in its optimization. Background: The study aimed at describing short and mid-term changes in CORVIS ST® parameters and indices in orthokeratology (ortho-k), and their diurnal variations. Methods: A prospective observational study was designed in which several CORVIS ST® parameters of 75 new adult participants successfully fitted with overnight ortho-k Seefree® (Conóptica - Hecht Contactlinsen) contact lenses were explored. Measurements were conducted in baseline (BL) conditions and in the morning and evening at the one night (1NM / 1NT), one week (1WM / 1WT) and 3 months (3MM / 3MT) follow-up visits. Results: Statistically significant differences were found in DARatio_2mm, IntRad, ARTh, CBI and TBI following overnight ortho-k, when compared with BL values, with most values reaching stability at 1WM or reverting to BL values at 3MM. The ARTh and CBI parameters showed some of the most significant temporal variations (both p<0.001), probably reflecting the encountered differences in central corneal thickness between BL and 1WM (p=0.010) and between BL and 3MM (p=0.016). In general, corneal rigidity was higher in the morning at all follow-up visits, and decreased during the day. No statistically significant changes in adjusted intraocular pressure values were found. Conclusion: Ortho-k in adults may be considered a safe procedure in terms of short and mid-term changes in CORVIS ST® parameters. The observed alterations in most of the parameters provided by the Corvis ST® probably responded to the well-described changes in corneal pachymetry and tomography, rather than to actual alterations in corneal rigidity., The author David P Piñero has been supported by the Ministry of Economy, Industry and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471., Peer Reviewed, Postprint (author's final draft)

Orthokeratology (ortho-k) is the process of deliberately reshaping the anterior cornea by utilising specialty contact lenses to temporarily and reversibly reduce refractive error after lens removal. Modern ortho-k utilises reverse geometry lens designs, made with highly oxygen permeable rigid materials, worn overnight to reshape the anterior cornea and provide temporary correction of refractive error. More recently, ortho-k has been extensively used to slow the progression of myopia in children. This report reviews the practice of ortho-k, including its history, mechanisms of refractive and ocular changes, current use in the correction of myopia, astigmatism, hyperopia, and presbyopia, and standard of care. Suitable candidates for ortho-k are described, along with the fitting process, factors impacting success, and the potential options for using newer lens designs. Ocular changes associated with ortho-k, such as alterations in corneal thickness, development of microcysts, pigmented arcs, and fibrillary lines are reviewed. The safety of ortho-k is extensively reviewed, along with an overview of non-compliant behaviours and appropriate disinfection regimens. Finally, the role of ortho-k in myopia management for children is discussed in terms of efficacy, safety, and potential mechanisms of myopia control, including the impact of factors such as initial fitting age, baseline refractive error, the role of peripheral defocus, higher order aberrations, pupil size, and treatment zone size.

PURPOSE. The International Myopia Institute (IMI) Yearly Digest highlights new research considered to be of importance since the publication of the first series of IMI white papers. METHODS. A literature search was conducted for articles on myopia between 2019 and mid-2020 to inform definitions and classifications, experimental models, genetics, interventions, clinical trials, and clinical management. Conference abstracts from key meetings in the same period were also considered. RESULTS. One thousand articles on myopia have been published between 2019 and mid-2020. Key advances include the use of the definition of premyopia in studies currently under way to test interventions in myopia, new definitions in the field of pathologic myopia, the role of new pharmacologic treatments in experimental models such as intraocular pressure-lowering latanoprost, a large meta-analysis of refractive error identifying 336 new genetic loci, new clinical interventions such as the defocus incorporated multisegment spectacles and combination therapy with low-dose atropine and orthokeratology (OK), normative standards in refractive error, the ethical dilemma of a placebo control group when myopia control treatments are established, reporting the physical metric of myopia reduction versus a percentage reduction, comparison of the risk of pediatric OK wear with risk of vision impairment in myopia, the justification of preventing myopic and axial length increase versus quality of life, and future vision loss. CONCLUSIONS. Large amounts of research in myopia have been published since the IMI 2019 white papers were released. The yearly digest serves to highlight the latest research and advances in myopia.

We conducted a prospective, paired-eye, investigator masked study in 30 children with myopia (−1.25 D to −4.00 D; age 10 to 14 years) to test the efficacy of a novel multifocal orthokeratology (MOK) lens compared to conventional orthokeratology (OK) in slowing axial eye growth. The MOK lens molded a center-distance, multifocal surface onto the anterior cornea, with a concentric treatment zone power of +2.50 D. Children wore an MOK lens in one eye and a conventional OK lens in the fellow eye nightly for 18 months. Eye growth was monitored with non-contact ocular biometry. Over 18 months, MOK-treated eyes showed significantly less axial expansion than OK-treated eyes (axial length change: MOK 0.173 mm less than OK; p < 0.01), and inner axial length (posterior cornea to anterior sclera change: MOK 0.156 mm less than OK, p < 0.01). The reduced elongation was constant across different baseline progression rates (range −0.50 D/year to −2.00 D/year). Visual acuity was less in MOK vs. OK-treated eyes (e.g., at six months, MOK: 0.09 ± 0.01 vs. OK: 0.02 ± 0.01 logMAR; p = 0.01). We conclude that MOK lenses significantly reduce eye growth compared to conventional OK lenses over 18 months.

Purpose: To determine the efficacy, predictability and safety of long-term orthokeratology in children and adults. Methods: Case histories of 300 orthokeratology patients (596 eyes; 34.3% children; 65.7% adults) were reviewed to collect information on demographics, corneal and refractive parameters, visual acuity, residual refraction and adverse effects. Predictability was defined as the percentage of eyes with absolute values of spherical equivalent refraction = 0.5 D of emmetropia, and efficacy as the ratio of post-orthokeratology uncorrected and pre-orthokeratology corrected distance visual acuity. Results: Median duration of treatment was 37 and 28.5 months in children and adults, respectively (p = 0.022). During the first year, 17.2% of children and 33% of adults ceased lens wear (p < 0.001). For children and adults with a successful ortho-k treatment of at least one year of duration, 88.7% and 95.9% of eyes had a predictable refractive outcome, and efficacy was 0.98 and 1.01, respectively. A larger percentage of children (65.7%) were free of complications than of adults (55.4%) (p = 0.015). One event of microbial keratitis occurred in adults (6.8 cases per 10,000 patient-years) and none in children. Corneal staining was the most frequent complication, with a higher incidence in adults (p = 0.007) and in higher myopia (p < 0.001), higher anterior corneal eccentricity (p = 0.019) and smaller anterior horizontal radius (p = 0.027). Conclusion: Orthokeratology is a safe and predictable long-term procedure in children and adults, with a low incidence of serious adverse effects. Corneal staining episodes are relatively frequent throughout the course of the treatment, thus highlighting the relevance of education of experienced users., Peer Reviewed, Postprint (author's final draft)

OBJECTIU: En l’actual estudi es va proposar investigar la influència de la ortoqueratologia nocturna (OKN) en la pressió intraocular (IOP), a curt i a mig termini, en usuaris novells. MÈTODES: Es va examinar l'ull dret de 76 pacients que van iniciar una adaptació d’OKN. Es va realitzar tonometria d'aire amb Topcon CT-80® (PIO), i amb CORVIS® ST (IOPnct), i tonometria biomecànicament corregida (bioP) amb CORVIS® ST, per mesurar la IOP abans de l'adaptació, i en diferents moments del temps durant el tractament. Es va mesurar també el gruix corneal central (CCT), amb CORVIS® ST. RESULTATS: La PIO es va trobar significativament reduïda (p=0.001) a la setmana de tractament, mentre que la IOPnct va arribar a estar significativament disminuïda als tres mesos (p=0.029). La bioP no va presentar canvis significatius en cap moment del temps (p=0.153). La IOP va presentar variacions diürnes significatives, menors per al mesurament amb bioP (p=0.004). No hi va haver correlació significativa entre els canvis en la tonometria i el CCT en el temps, ni durant el dia. CONCLUSIÓ: La OKN indueix canvis significatius a curt termini en les lectures de la tonometria no corregida relacionats amb modificacions en la biomecànica corneal, però no en la bioP., OBJETIVO: En el presente estudio se propuso investigar la influencia de la ortoqueratología nocturna (OKN) en la presión intraocular (IOP), a corto y a medio plazo, en usuarios noveles. MÉTODOS: Se examinó el ojo derecho de 76 pacientes que iniciaron una adaptación de OKN. Se realizó tonometría de aire con Topcon CT-80® (PIO), y con CORVIS® ST (IOPnct), y tonometría biomecánicamente corregida (bioP) con CORVIS® ST, para medir la IOP antes de la adaptación, y en diferentes momentos del tiempo durante el tratamiento. Se midió también el espesor corneal central (CCT), con CORVIS® ST. RESULTADOS: La PIO se halló significativamente reducida (p=0.001) a la semana de tratamiento, mientras que la IOPnct llegó a estar significativamente disminuida a los tres meses (p=0.029). La bioP no presentó cambios significativos en ningún momento del tiempo (p=0.153). La IOP presentó variaciones diurnas significativas, menores para la medición con bioP (p=0.004). No hubo correlación significativa entre los cambios en la tonometría y el CCT en el tiempo, ni durante el día. CONCLUSIÓN: La OKN induce cambios significativos a corto plazo en las lecturas de la tonometría no corregida relacionados con modificaciones en la biomecánica corneal, pero no en la bioP., PURPOSE: The present study aimed to investigate the influence of overnight orthokeratology (OKN) on intraocular pressure (IOP), in the short and medium term, in novice users. METHODS: The right eye of 76 patients who started an OKN fitting was examined. Air tonometry with Topcon CT-80® (PIO), and with CORVIS® ST (IOPnct), and biomechanically corrected tonometry (bioP) with CORVIS® ST, were performed to measure IOP before fitting, and at different time points during treatment. Central corneal thickness (CCT) was also measured with CORVIS® ST. RESULTS: PIO was found to be significantly reduced (p=0.001) at one week of treatment, while IOPnct became significantly decreased at three months (p=0.029). BioP did not show significant changes at any time point (p=0.153). IOP presented significant diurnal variations, lower for bioP measurement (p=0.004). There was no significant correlation between changes in tonometry and CCT over time, nor during the day. CONCLUSION: OKN induces significant short-term changes in uncorrected tonometry readings related to modifications in corneal biomechanics, but not in bioP.

OBJECTIUS: Analitzar mitjançant un sistema de doble pas l’efecte que produeix el tractament d’ortoqueratologia en la qualitat òptica de l’ull entre la base (no haver portat lents de contacte), l’ús d’un dia, d’una setmana i de tres mesos i també entre matí i tarda. MÈTODES: Es van avaluar 30 pacients (60 ulls), amb edats compreses entre 18 i 54 anys, miops fins a -5,00D i astigmatismes fins a -1,50 D. A totes les visites, es van avaluar els canvis que hi van haver entre les variables Objective Scattering Índex (OSI), Strehl Ratio (SR), freqüència de tall de la Funció de Transferència de Modulació (MTFCUTOFF), refracció subjectiva i el bestfocus (millor imatge retiniana adquirida per l’instrument amb el millor enfoc) amb l’OQAS-II. L’anàlisi de dades es va realitzar amb el programa estadístic SPSS. RESULTATS: S’observen diferències estadísticament significatives en totes les variables entre la base i la resta de dies. En comparació entre matí i tarda, hi ha afectació en la refracció subjectiva en el primer dia d’ús i als tres mesos. L’OSI es veu també afectada en el primer dia d’ús. Respecte a la MTF i el SR no hi ha diferències estadísticament significatives entre el matí i la tarda. CONCLUSIONS: Hi ha una disminució de la qualitat òptica entre la base i el primer dia d’ús però amb una estabilitat a partir d’aquesta fins els tres mesos. La refracció va disminuint a mesura que es dorm més nits amb les lents de contacte fins aproximadament una setmana d’ús, on s’estabilitza. Respecte al matí i a la tarda, hi ha un augment de la refracció a últimes hores de la tarda i una disminució de l’OSI.

The first papers on the fitting of ortho-k lenses in ametropic individuals, treatment that allows them to enjoy good vision without the need to wear glasses or contact lenses, were published almost 60 years ago. Both the reversibility of the treatment when the lenses are discontinued, as well as the slight loss of the effect suffered by users throughout the day have been studied, but there is no paper to date that justifies or foresees diurnal regression based on corneal biomechanical properties provided by the Corvis ST® tonometer. OBJECTIVES: To assess how the corneal and visual parameters vary throughout the day, in the short and medium term, after having slept with orthokeratology lenses, and relate them to the baseline data of visual acuity, refraction, topographic and biomechanical properties, in this way, to help clinicians make a better prognosis in front of a potential orthokeratology treatment. We also wanted to verify whether the parameters related to corneal biomechanics vary after orthokeratology treatment. METHODS: 75 adults with myopia between -0.50 and -5.00 D with a corneal and refractive astigmatism lower than -1.25 D, were recruited to be fitted at the Center Universitari de la Visió (FOOT-UPC) with Seefree® orthokeratology lenses (Conóptica - Hecht Contactlinsen), spherical or toric, as required by each individual. Baseline measurements of LogMAR visual acuity, refraction, corneal tomography (Pentacam®), corneal biomechanics (Corvis ST®) and intraocular pressure (CT-80®) were performed. After starting to sleep with the orthokeratology lenses, the same measurements were repeated after the first night of use, after one week and after three months, twice a day, one in the morning and one in the afternoon, 8 hours apart between both visits. RESULTS: 69 patients reached the weekly control and 49 the quarterly. None of the dropouts responded to severe complications. A mean diurnal regression of 0.25 D was found throughout the day at all moments evaluat, Fa quasi 60 anys de les primeres publicacions sobre l'adaptació de lents d'orto-k en individus ametrops, tractament que els permet gaudir d'una bona visió sense la necessitat de fer servir ulleres o lents de contacte. Hi ha estudis tant sobre la seva reversibilitat refractiva al deixar de fer servir les lents, com de la lleu perduda d'efecte que pateixen els usuaris al llarg del dia, però cap a dia d'avui que justifiqui o prevegi la regressió diürna en funció de les propietats biomecàniques corneals aportades pel tonòmetre Corvis ST®. OBJECTIUS: Avaluar com varien els paràmetres corneals i visuals al llarg del dia, a curt i mitja terme, després d'haver dormit amb lents d'ortoqueratologia i relacionar-los amb les dades de partida d'agudesa visual, refractius, topogràfics i biomecànics, per d'aquesta forma, ajudar als clínics a realitzar un millor pronòstic davant un potencial tractament ortoqueratològic. També es va voler comprovar si els paràmetres relatius a la biomecànica corneal varien després del tractament ortoqueratològic. MÈTODES: 75 adults amb miopies entre -0,50 i -5,00 D i amb un astigmatisme refractiu i corneal inferior a -1,25 D van ser reclutats per ser adaptats al Centre Universitari de la Visió (FOOT-UPC) amb lents d'ortoqueratologia Seefree® (Conóptica Hecht Contactlinsen), esfèriques o tòriques segons requerís cada individu. Es van fer mesures basals d'agudesa visual LogMar, refracció, tomografia corneal (Pentacam®), biomecànica corneal (Corvis ST®) i pressió intraocular (CT-80®). En començar a dormir amb les lents d'ortoqueratologia es van repetir les mateixes mesures després de la primera nit d'us, a la setmana i als tres mesos, dues vegades al dia, una al matí i una altra a la tarda, amb 8 hores de diferència entre ambdues visites. RESULTATS: 69 pacients van arribar al control setmanal i 49 al trimestral. Cap dels abandonaments va respondre a complicacions severes. Es va trobar una regressió diürna mitja de 0,25 D al llarg del dia a tots els mome, Hace ya casi 60 años de las primeras publicaciones sobre la adaptación de lentes de orto-k en individuos amétropes, tratamiento que les permite gozar de una buena visión sin la necesidad de usar gafas o lentes de contacto. Hay estudios tanto sobre la reversibilidad refractiva al dejar de usar las lentes, como de la leve pérdida de efecto que sufren los usuarios a lo largo del día, pero ninguno a día de hoy que justifique o prevea la regresión diurna en función de las propiedades biomecánicas corneales aportadas por el tonómetro Corvis ST®. Evaluar cómo varían los parámetros corneales y visuales a lo largo del día, a corto y medio plazo, después de haber dormido con lentes de ortoqueratología, y relacionarlos con los datos de partida de agudeza visual, refractivos, topográficos y biomecánicos, para de esta forma, ayudar a los clínicos a realizar un mejor pronóstico frente un potencial tratamiento ortoqueratológico. También se quiso comprobar si los parámetros relativos a la biomecánica corneal varían tras el tratamiento ortoqueratológico. 75 adultos con miopías entre -0,50 y -5,00 D y con un astigmatismo refractivo y corneal inferior a -1,25 D, fueron reclutados para ser adaptados en el Centre Universitari de la Visió (FOOT-UPC) con lentes de ortoqueratología Seefree® (Conóptica - Hecht Contactlinsen), esféricas o teóricas, según requiriese cada individuo. Se realizaron medidas basales de agudeza visual LogMAR, refracción, tomografía corneal (Pentacam®), biomecánica corneal (Corvis ST®) y presión intraocular (CT-80®). Tras empezar a dormir con las lentes de ortoqueratología se les repitieron las mismas mediciones tras la primera noche de uso, a la semana y a los tres meses, dos veces cada día, una por la mañana y otra por la tarde, con 8 horas de diferencia entre ambas visitas. 69 pacientes llegaron al control semanal y 49 al trimestral. Ninguno de los abandonos respondió a complicaciones severas. Se encontró una regresión diurna media de 0,25 D a lo largo del día en, Postprint (published version)

La miopia suposa una gran preocupació per als professionals de la salut, a causa de la ràpida extensió de la mateixa envers la població mundial i la seva aparició cada vegada més precoç. L'objectiu d'aquest treball és aprofundir en la literatura científica més actual relativa a les diferents teràpies per al control de la progressió de la miopia, així com revelar les tècniques més innovadores i eficaces. També ressaltar la prevalença i els factors de risc a Espanya i el món. Informació extreta de plataformes especialitzades com PubMed, Scielo, Dialnet, entre d'altres. Els estudis mostren que han sorgit diversos sistemes de control miòpic, dels quals només alguns d'ells han demostrat la seva eficàcia, amb millors resultats en la població més jove. Les causes més rellevants que afavoreixen l'aparició i progressió de la miopia són els factors ambientals, educacionals, professionals, i la procedència geogràfica. S'ha comprovat, respecte a la prescripció de l'atropina, que el percentatge que manifesta millors resultats conjuntament amb menors efectes secundaris és la seva aplicació a l'0,01%. Al mateix temps les LC multifocals i Orto-K han obtingut resultats molt positius, de manera que aquestes tres tècniques són les considerades més eficaces actualment i les que més s'estan investigant., La miopía supone una gran preocupación para profesionales de la salud, a causa de la rápida extensión de la misma en la población mundial y su aparición cada vez más precoz. El objetivo de este trabajo es profundizar en la literatura científica más actual, relativa a las diferentes terapias para el control de la progresión de la miopía, así como revelar las técnicas más novedosas y eficaces. También resaltar la prevalencia y los factores de riesgo en España y el mundo. Información extraída de plataformas especializadas como PubMed, Scielo, Dialnet, entre otras. Los estudios muestran que han surgido diversos sistemas de control miópico, de los cuales sólo algunos de ellos han demostrado su eficacia, con mejores resultados en la población más joven. Las causas más relevantes que favorecen la aparición y progresión de la miopía son los factores ambientales, educacionales, profesionales, y la procedencia geográfica. Se ha comprobado, respecto a la prescripción de la atropina, que el porcentaje que arroja mejores resultados conjuntamente con menores efectos secundarios, es su aplicación al 0,01%. Al mismo tiempo las LC multifocales y Orto-K han obtenido resultados muy positivos, de modo que estas tres técnicas son las consideradas más eficaces actualmente y las que más se están investigando., Myopia is of great concern to health professionals because of its rapid spread in the world population and its increasingly early onset. The aim of this thesis is to review the most current scientific literature on the different therapies for the control of myopia progression, as well as to reveal the latest and most effective techniques. It also highlights the prevalence and risk factors in Spain and the world. Information extracted from specialised platforms such as PubMed, Scielo, Dialnet, among others. Studies show that various myopic control systems have emerged, only some of which have proven to be effective, with better results in the younger population. The most relevant causes that favour the appearance and progression of myopia are environmental, educational, professional factors and geographical origin. With regard to the prescription of atropine, it has been proven that the percentage that yields the best results together with the fewest side effects is its application at 0.01%. At the same time, multifocal LC and Ortho-K have obtained very positive results, so that these three techniques are currently considered to be the most effective and are the most researched.

Accepted March 11, 2019, Purpose: To assess the correlation between anterior corneal elevation (ACE) and anterior corneal astigmatism (ACA) obtained with two different topographers in healthy subjects at different corneal diameters. Methods: A retrospective, comparative, and observational study was conducted. Topography data from 305 patients obtained with the Oculus Pentacam (Oculus, Wetzlar, Germany) and Sirius (CSO, Florence, Italy) systems were collected. Subjects were divided into four groups depending on the magnitude of ACA. The ACE was evaluated in the principal meridians at 2, 3, and 4 mm from the corneal apex. The difference in ACE between meridians (ACE-M) and in superior-inferior and nasal-temporal semimeridians (ACE-SM) was calculated. Results: A strong positive correlation between ACE-M and ACA with both topographers was found for all corneal diameters (P<0.001). A linear equation to calculate the ACE-M differences as a function of the astigmatism at 8 mm of diameter was obtained: y=23.417x+1.40, where y is ACE-M in microns and x is ACA in diopters. Significant differences in ACE along SM were found for all groups studied according to the magnitude of ACA for the horizontal SM (P>0.001). The temporal meridian was more elevated at 4- and 6-mm diameters, and the nasal semimeridian was the most elevated for 8 mm. Conclusion: Anterior corneal astigmatism and elevation differences are strongly correlated, providing more corneal topography knowledge that could be applied in the contact lens fitting. A toric orthokeratology lens may be indicated in ACA greater than 0.75 D., Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Received: 24 October 2018; Revised: 12 September 2019; Accepted: 03 October 2019; First Online: 12 November 2019, Purpose: To evaluate the changes in the accommodative response and in the corneal and internal spherical aberration during three months of wear of orthokeratology lenses from the baseline. Methods: Fifty children aged 8 to 17 were recruited for a prospective study and were fitted with orthokeratology lenses. Refraction without cycloplegia, high and low uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), accommodation lag, horizontal near phoria without correction, corneal topography, corneal and total wavefront aberration were performed at baseline, 1 day, 1 week, 1 month and 3 months. Data were analysed by Student t-test for related samples, repeated measures ANOVA test and Pearson Correlation test. Results: The spherical equivalent (SE) before and after three months was -3.33 ± 1.60 D and -0.30±0.46 D, respectively. Accommodation lag was 0.53±0.38 D and 0.20±0.33 D at baseline and at three months, respectively. A moderate correlation between lag at the baseline and its change between baseline and the 3-month visit was found (P<0.05; R= 0.748). The spherical aberration (SA) increased for anterior corneal and total measurement, being statistically significant for all visits (P<0.05). The internal SA decreased: -0.105±0.006 at baseline and -0.196±0.203 at 1 week (P< 0.05). No difference between baseline and the follow up visits in posterior corneal SA was found (P>0.05) Conclusion: The negative SA of the lens increases during OK treatment compensated for the increase of the anterior corneal surface positive SA, in addition to increasing the accommodative response., Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Pediatric myopia has become a major international public health concern. The prevalence of myopia has undergone a significant increase worldwide. The purpose of this review of the current literature was to evaluate the peer-reviewed scientific literature on the efficacy and safety of low-dose atropine treatment combined with overnight orthokeratology for myopia control. A search was conducted in Pubmed and Web of Science with the following search strategy: (atropine OR low-dose atropine OR 0.01% atropine) AND (orthokeratology OR ortho-k) AND (myopia control OR myopia progression). All included studies improved myopia control by the synergistic effect of orthokeratology with low-dose atropine, compared with orthokeratology treatment alone. All studies included a short or medium follow-up period; therefore longer-term studies are necessary to validate these results.

Purpose: To compare the changes in higher order aberrations (HOA’s) for photopic and mesopic pupil diameters in children undergoing orthokeratology treatment (OK) or combined 0.01% atropine with orthokeratology treatment (AOK), and their association with axial elongation. Methods: Children aged 6 to <11 years with 1.00–4.00 D of myopia were randomly assigned to each treatment group. Photopic and mesopic pupil diameters were quantified using automated pupillometry and HOA’s were measured with a Hartmann-Shack aberrometer and Badal system to control for accommodation. HOA’s were rescaled to photopic and mesopic pupil diameters and fitted with a 6th order Zernike polynomial expansion. Axial length was measured using an optical biometer under cycloplegia. Results: Baseline and six-month data from 25 AOK and 28 OK participants were analysed. At the six-month visit, pupil diameter was larger in the AOK group under photopic conditions (3.70 ± 0.42 vs 3.12 ± 0.33 mm, p < 0.001), along with a range of HOA metrics [3rd to 6th order and higher order root mean square error values (HO RMS), all p ≤ 0.003] and individual Zernike terms (primary spherical aberration, and oblique quadrafoil, both p ≤ 0.03). Axial elongation was greater in the OK treatment group (0.05 ± 0.08 vs −0.01 ± 0.12 mm, p = 0.02). In the AOK group, axial elongation was correlated with the increase in photopic pupil diameter (r = −0.45, p = 0.02) and with several HOA metrics; however, these associations were not observed in the OK group. Conclusion: AOK treatment resulted in increased photopic pupil size and HOA’s, and significantly less axial elongation over a six-month period compared to OK treatment alone. The improved myopia control observed with combination 0.01% atropine and orthokeratology may be a result of an enhanced optical effect due to a larger photopic pupil size.

Purpose: To summarize the peer-reviewed literature on corneal structural changes after orthokeratology (OK) and to analyze the quality of the studies published. Methods: An exhaustive search was carried out in the databases Pubmed MEDLINE, Web of Science and Scopus. Original studies in English, with a cohort or experimental design and analyzing the cellular and structural changes of the cornea after OK fitting for myopia correction were selected. The NewCastle-Ottawa Assessment Scale (NOS) tool was used to analyze the quality of the studies selected. Results: The search provided a total of 1837 articles, of which 12 were selected following the inclusion and exclusion criteria. All studies had good quality according to the NOS tool (mean 7.58 ± 1.31). The mean ± standard deviation follow-up period of lens wear in the studies evaluated was 19.27 ± 33.97 months. The following reversible changes after OK have been reported: reduction in central epithelial basal cells, an increase in height and especially in width of superficial epithelial cells, as well as an increase in central stromal thickness and in the number of active keratocytes. Concerning corneal endothelium, only changes in terms of polymegathism were reported that were compatible with those observed for other types of contact lens wear. In relation to corneal sensitivity, there was a reduction during the use of OK, as well as in the nervous density of the sub-basal plexus at the central level, with some contradictory outcomes concerning the reversibility of these changes. Conclusion: OK produces reversible structural changes in the central epithelium and central anterior corneal stroma, as well as a decrease in the nerve density of the sub-basal plexus and corneal sensitivity. The quality of published studies evaluating these aspects is good, although more studies are needed to evaluate longer follow-up changes.

Purpose: Orthokeratology (OK) is known to alter relative peripheral refraction (RPR) with this presumed to be its key myopia control mechanism. A prospective, longitudinal study was performed to examine stability of OK-induced RPR changes in myopic children and young adults. Methods: RPR of twelve children (C)(8–16 years) and eight adults (A)(18–29 years) with spherical equivalent refraction of -0.75 to -5.00D were measured unaided and while wearing single vision soft contact lenses (SCL). Measurements were repeated after 1, 6 and 12 months of OK wear. RPR was measured using an open-field Shin Nippon SRW-5000 autorefractor at 10, 20 and 30 degrees nasally (N) and temporally (T), converted into power vectors M, J0 and J45. On-axis refractions and axial lengths (IOL Master) were also measured. Results: Compared to the unaided state, 1-month of OK wear shifted the RPR in the myopic direction at 30 T (C: p = 0.023; A:, p = 0.002) and 30 N (C&A, p = 0.003) and was stable thereafter, with similar changes compared to SCL wear. J0 showed a myopic shift in comparison to both unaided and SCL correction in children but not adults, and J45 did not change in either group. The on-axis OK correction was predictive of the RPR shift in both children and adults at 30 T (C: r=−0.58, p = 0.029; A: r=−0.92, p < 0.001) and 30 N (C: r=−0.60, p = 0.024; A: r=−0.74, p = 0.013) with symmetry of RPR shifts (C: r = 0.67, p = 0.008; A: r = 0.85, p = 0.004). No relationships between changes in RPR and axial length were found after twelve months of OK wear; level of myopia was stable in both groups. Conclusion: Relative to both unaided and single vision SCL correction, OK shifted the RPR in the myopic direction; the RPR was stable from 1 to 12 months. The RPR shift in OK wear varied with the degree of myopia but was not correlated with myopia progression.

Purpose: To assess the correlation between anterior corneal elevation (ACE) and anterior corneal astigmatism (ACA) obtained with two different topographers in healthy subjects at different corneal diameters. Methods: A retrospective, comparative, and observational study was conducted. Topography data from 305 patients obtained with the Oculus Pentacam (Oculus, Wetzlar, Germany) and Sirius (CSO, Florence, Italy) systems were collected. Subjects were divided into four groups depending on the magnitude of ACA. The ACE was evaluated in the principal meridians at 2, 3, and 4 mm from the corneal apex. The difference in ACE between meridians (ACE-M) and in superior–inferior and nasal–temporal semimeridians (ACE-SM) was calculated. Results: A strong positive correlation between ACE-M and ACA with both topographers was found for all corneal diameters (P<0.001). A linear equation to calculate the ACE-M differences as a function of the astigmatism at 8 mm of diameter was obtained: y=23.417x+1.40, where y is ACE-M in microns and x is ACA in diopters. Significant differences in ACE along SM were found for all groups studied according to the magnitude of ACA for the horizontal SM (P>0.001). The temporal meridian was more elevated at 4- and 6-mm diameters, and the nasal semimeridian was the most elevated for 8 mm. Conclusion: Anterior corneal astigmatism and elevation differences are strongly correlated, providing more corneal topography knowledge that could be applied in the contact lens fitting. A toric orthokeratology lens may be indicated in ACA greater than 0.75 D.

Purpose: To evaluate the preliminary clinical outcomes of a new contact lens design for orthokeratology in hyperopia. Methods: Prospective pilot study including 8 hyperopic eyes of 4 nonpresbyopic patients (24–44 years) undergoing orthokeratology with the Alexa H contact lens (Tiedra Pharmaceutical, Madrid, Spain), which is an aspheric pentacurve design. Visual, refractive, corneal topographic, and aberrometric changes were evaluated during a 1-month follow-up. Likewise, the presence of ocular surface alterations was evaluated by slit-lamp biomicroscopy during this follow-up. Results: Mean noncyclopegic sphere decreased significantly from a mean prefitting value of 2.94±0.95 D to mean values of 1.18±1.19 (P=0.01) and 0.25±0.85 D (P=0.04) at 1 week and 1 month of lens wear, respectively. Statistically significant changes were detected at 1 week of use of the lenses in keratometry (P=0.03), asphericity (Q) (P=0.01), and the Zernike term for corneal spherical aberration (SA) (P=0.01). However, no significant changes were observed in uncorrected (P=0.68) and best-corrected distance visual acuity (P=0.18). Superficial corneal staining was observed after the first night of use in only 1 patient who was resolved spontaneously. Likewise, the induction of a “toroid-like” topographic pattern leading to poor visual outcome and suboptimal correction was observed in four eyes at the beginning of the treatment. This condition was solved in all cases by reducing the lens diameter. Conclusion: The Alexa H lens seems to be useful for providing an orthokeratologic correction of hyperopia, with generation of increased negative Q and SA, and central steepening. However, fitting guides must be improved to avoid suboptimal outcomes as those related to the “toroid-like” topographic pattern defined.

Background: To investigate the influence of compression factor upon changes in ocular higher-order aberrations (HOAs) in young myopic children undergoing orthokeratology treatment. Methods: Subjects aged between six and < 11 years, with low myopia (0.50–4.00 D inclusive), low astigmatism (≤ 1.25 D), and anisometropia (≤ 1.00 D), were randomly assigned to wear orthokeratology lenses of different compression factors in each eye (one eye 0.75 D and the fellow eye 1.75 D). HOAs were measured weekly over one month of lens wear. Wavefront analysis was conducted over a 5-mm pupil using a sixth order Zernike polynomial expansion. Linear mixed models were used to examine the individual Zernike co-efficients and specific root-mean-square (RMS) error (spherical, comatic, total HOAs) metrics and their changes between the two eyes during the study period. Results: Twenty-eight myopic (mean manifest spherical equivalent refraction: −2.10 ± 0.58 D) children (median [range] age: 9.3 [7.8–11.0] years) were analysed. Significant interocular differences in HOAs at baseline were observed for (Z6 -6) and ((Z6 -4) only (both p < 0.05). During the lens wear period, eyes fitted with the increased compression factor showed greater changes in primary spherical aberration (Z4 0, p = 0.04) and RMS values for spherical and total HOAs (both p < 0.01). Considering data from both eyes together, after adjusting for the paired nature of the data, some other Zernike terms (Z3 1) and (Z6 0), both p < 0.01) and the RMS value of comatic aberrations (p < 0.001) significantly increased after one month of orthokeratology treatment. The increase in primary spherical aberration (Z4 0) was positively correlated with the reduction in spherical equivalent refractive error, but only in eyes fitted with the increased compression factor (r = 0.69, p < 0.001). Conclusions: Increasin

Objectiu. Avaluar el comportament de la còrnia i l’evolució dels paràmetres cornials després de l’ús de les lents d’ortoqueratologia. Métodes. Es van avaluar 76 subjectes (152 ulls), amb edats compreses entre 18 i 50 anys, miops fins -5,50D i astigmatismes fins -2,00D. En cada visita (1 dia, 1 setmana, 3 mesos) es van avaluar els canvis topogràfics i biomecànics de la còrnia després de l’ús de les lents d’ortoqueratologia Seefree® amb els instruments Oculus Pentacam® i Corvis® ST, respectivament. L’anàlisi estadística es va realitzar amb SPSS 26.0. Resultats. Es troben diferències estadísticament significatives en els paràmetres topogràfics i biomecànics entre totes les visites excepte entre la visita d’una setmana i tres mesos, en les que no hi ha canvis significatius en la majoria de les variables. Es troben correlacions entre alguns paràmetres del Corvis® ST (ARTh, IntegrRadius i DAratio) en la visita preliminar amb alguns paràmetres del Pentacam® de les visites posteriors. Conclusions. L’ortoqueratologia produeix canvis als paràmetres biomecànics i topogràfics de la còrnia a curt i mitjà termini. Es podrien utilitzar alguns paràmetres obtinguts amb el Corvis ST per predir l’èxit de l’adaptació de les lents d’ortoqueratologia a mitjà termini.

Received 18 October 2018; Revised 29 November 2018; Accepted 16 December 2018; Published 2 January 2019, Purpose. To evaluate the effect of the optical zone diameter (OZ) in orthokeratology contact lenses regarding the topographical profile in patients with high myopia (−4.00 D to −7.00 D) and to study its effect over the visual quality. Materials and Methods. Twelve patients (18 eyes) were fitted with overnight orthokeratology (OrthoK) with a randomized 6 mm or 5 mm OZ lens worn for 2 weeks, followed by a 2-week washout period, between both designs. Keratometry (K) readings, optical zone treatment diameter (OZT), peripheral ring width (PRW), higher-order aberrations (HOA), high (HC) and low contrast (LC) visual acuity, and subjective vision and comfort were measured at baseline and after 2 weeks of OrthoK lens wear of each contact lens. Results. No significant differences were found between any measurements for the same subject at both baselines ( value > 0.05). There was no difference between OZ lens designs found in refraction, subjective vision or comfort, and HC and LC visual acuity. Contrast sensitivity was decreased in the 5 mm OZ lens design compared with 6 mm OZ design (-value < 0.05). 5 mm OZ design provoked a greater flattening, more powerful midperipheral ring and 4th-order corneal and total spherical aberration than the 6 mm OZ design, being statistically significant after 7 days, for corneal aberration, and 15 days, for corneal and total, of wearing the lens (-value < 0.05). The OZT obtained were 2.8 ± 0.2 mm and 3.1 ± 0.1 mm for 5 mm and 6 mm OZ design, respectively (-value < 0.05). Regarding PRW, the 5 mm OZ design had a wider ring width in both the nasal and temporal zones (-value < 0.05). Conclusions. A smaller diameter optical zone (5 mm) in orthokeratology lenses produces a smaller treatment area and a larger and more powerful midperipheral ring, increasing the 4th-order spherical aberration that affects only the contrast sensitivity but without differences in visual acuity and subjective vision compared with a larger OZ diameter (6 mm)., Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Received 28 February 2019; Accepted 28 February 2019; Published 8 April 2019., Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Objective: To investigate the repeatability of choroidal thickness measurements determined from enhanced depth imaging optical coherence tomography (EDI-OCT) images of eyes after wearing single-vision spectacles (SV) and orthokeratology (ortho-k) lenses. Methods and analysis Two EDI-OCT images of 40 children (SV: 20, ortho-k: 20) taken at a single visit were analysed twice. Subjects in the ortho-k group had been wearing ortho-k for 1–4 weeks. The choroidal thickness was determined from each image using a graph theory-based software and, where appropriate, manual correction of choroidal boundaries was undertaken by an experienced examiner. Results The mean (±SD) choroidal thickness was 227.3±42.2 µm for the SV subjects and 251.1±54.4 µm for the ortho-k subjects. The interimage differences in choroidal thickness were −0.99±3.54 and −1.14±5.03 µm for the SV and ortho-k subjects, respectively, and the limits of agreement were +5.96 to −7.93 and +8.72 to −11.00 µm, respectively. Conclusion: The coefficients of repeatability of choroidal thickness measurements from two EDI-OCT images taken at a single visit were 7.08 µm (SV) and 10.06 µm (ortho-k), suggesting that a change in choroidal thickness of less than 10 µm may not indicate a real change resulting from ortho-k lens wear.

Purpose: To determine the influence of compression factor upon changes in axial length and choroidal thickness during and following orthokeratology treatment. Methods: Orthokeratology lenses of different compression factors (one eye with 0.75 D and the fellow eye with 1.75 D) were randomly assigned to 28 subjects (median [range] age: 9.3 [7.8–11.0] years). Ocular biometrics were measured weekly for 1 month of lens wear and after lens cessation until the refraction stabilized (mean duration: 2.8 ± 0.4 weeks). Changes between eyes, and the associations between axial shortening and choroidal thickening with other ocular biometrics were analyzed. Results: There were no significant between-eye differences in the changes of ocular biometrics (all P > 0.05). After adjusting for paired-eye data, axial length initially decreased by 26 ± 41 µm (P = 0.03) at week 1, then gradually returned to its original length. An approximate antiphase relationship of choroidal thickness (mean change: 9 ± 12 µm, P < 0.001) with axial length was observed. A significant rebound in axial length, but not choroidal thickness, occurred during the cessation period. Central corneal thinning and choroidal thickening accounted for 70% of initial axial shortening. Conclusions: Increasing the compression factor by 1.00 D did not affect changes in ocular biometrics in short-term orthokeratology. Significant axial shortening and choroidal thickening were observed during early treatment period. Axial shortening could not be entirely explained by central corneal thinning and choroidal thickening, which warrants further investigation. Translational Relevance: Initial axial shortening in orthokeratology is transient and therefore axial length remains useful for long-term monitoring of axial elongation in children.

Purpose: To determine the extent of orthokeratology (OK) contact lens fitting worldwide and to characterize associated demographics and fitting patterns. Methods: Survey forms were sent to contact lens fitters in 45 countries between January and March every year for 14 consecutive years (2004 – 2017, inclusive). Practitioners were asked to record data relating to the first 10 contact lens fits or refits performed after receiving the survey form. Results: Data were obtained for 295,044 contact lens fits, of which 2,702 were with OK lenses and 292,342 were with other lens types (non-OK). Overall, OK lenses represented 1.2% of all contact lens fits, with significant differences between nations (p < 0.0001), ranging from no fits recorded in Brazil, Egypt, Indonesia, Iran, Lithuania, Nepal and the United Arab Emirates, to 6.0% in The Netherlands. There has been a slight overall increase in OK lens fitting over the survey period (p < 0.0001). OK lenses were fitted to younger persons (OK, 25.0 ± 12.8 years vs. non-OK, 39.8 ± 14.9 years) (p < 0.0001). A higher proportion of males (55%) were fitted with OK lenses versus non-OK lenses (30%) (p < 0.0009). There was a skewed distribution towards OK lenses being fit with higher oxygen permeable materials (p < 0.0001) and on a planned replacement basis (p < 0.0001). Conclusions: OK contact lens prescribing is a niche activity, with this lens type typically being fitted in high oxygen permeable materials on a planned replacement basis to younger males. The slightly increasing rate of OK fitting, albeit at a very low level, may be attributed to practitioner interest in the reported myopia control properties of this lens type.

Actualment notem un gran increment de miopia arreu del món, per tant s’han posat en pràctica tractaments per resoldre aquesta pandèmia. Un d’ells és l’ortoqueratologia, aquesta tècnica permet la compensació total o parcial de l’error refractiu durant el dia, fent ús d’una lent de contacte rígida durant la nit, adaptada amb la finalitat de moldejar la còrnia i prescindir de compensació durant el dia. En aquest treball s’explica en que tracta l’ortoqueratologia i l’evolució, així com les complicacions més comunes de les lents de contacte en general. Es fa una recerca bibliogràfica d’estudis realitzats en grups de pacients portadors de lents de contacte de diferents tipus i diferents reemplaçaments. A partir d’això s’obté unes conclusions de la prevalença de complicacions en totes elles, amb la finalitat de veure quines són les complicacions més comunes de l’ortoqueratologia i amb major incidència respecte a les altres modalitats de lents de contacte.

Accepted July 11, 2017, Objective: To compare, in terms of efficacy, the differences between the use of saline solution and a viscous artificial tear to fill the lens during the first month of orthokeratology wear. Methods: A pilot, double-masked, crossed, randomized, and prospective study was conducted. In this study, 20 subjects (14 males and 6 females) with a mean age of 16.29±6.22 years (range, 10–26) were fitted with orthokeratology contact lenses. For the study, nonpreserved 0.9% NaCl commercial saline solution (Avizor, Madrid, Spain) and nonpreserved artificial teardrops with 0.3% of hyaluronic acid (Ocudry 0.3%; Avizor, Madrid, Spain) were used. Corneal staining, tear break up time (TBUT), topography, refraction, visual acuity, and subjective comfort and vision with the visual analog scale (score from 0 to 10, being 10 better comfort and vision) were evaluated at 1 day, 1 week, and 1 month of contact lens wear. Results: The corneal staining was statistically greater in the saline group than in the Ocudry group for the first day and during 1 week of wear (P<0.05). Comfort was found to be statistically better, with Ocudry 0.3% than saline solution, being 7.17±1.94 and 6.37±1.63, for the first day, and 8.78±0.43 and 8.15±0.62 for the day 28, respectively (P<0.05). However, no differences were found for subjective vision scores, TBUT, spherical equivalent, best-corrected visual acuity and uncorrected visual acuity, and mean keratometry between groups for any visit (P>0.05). Conclusion: Viscous artificial tears improve the subjective comfort of patients and reduce the corneal staining, compared with saline solution during the orthokeratology lenses fitting process. However, no differences between solutions for the treatment efficacy, in vision and corneal topography, were found., Ministerio de Ciencia e Innovación (MICINN), RETICS (España), Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Both animal and human studies have demonstrated that the peripheral retina influences central refractive error development. It is hypothesised that peripheral hyperopic defocus may act as a strong stimulus for axial eye elongation. However, conflicting reports have been published suggesting no influence of peripheral refraction on human central refractive error development. Therefore, the role of the peripheral retina on myopia development in human eyes is yet to be understood. Interestingly, optical treatments that have been developed to induce peripheral myopic defocus using peripheral add power have been found to show some myopia control effects, indicating peripheral refraction may play a role in myopia development. Currently, orthokeratology (OK) is considered as the most effective optical treatment for myopia control. It is hypothesised that mid-peripheral corneal steepening may induce peripheral myopic defocus changes in myopic eyes treated with conventional OK lenses. However, there is large variability in myopia control outcomes with OK treatment which may be due to differences in ocular shape and peripheral refraction among individuals. Attempts to individualise peripheral optical defocus changes through manipulation of anterior corneal shape using OK lens designs are tedious and time consuming. Instead of manipulating the anterior corneal shape, this thesis aims to use large diameter (LD) rigid lenses as a novel optical model to induce peripheral defocus changes by anterior contact lens surface manipulations to mimic the OK optical treatment effect. However, before manipulating the front surface profile of these LD contact lenses, there was a need to understand the fitting aspects of LD contact lenses.To investigate the fitting aspects of LD contact lenses, the CASIA swept source (SS) anterior segment optical coherence tomographer (OCT) was used extensively in the research studies reported in this thesis. It has been reported previously that OCT instrumen

Orthokeratology (OK) contact lenses have shown propensity for slowing down the worsening of myopia in children and young adults, with only some understanding of the mechanism. This thesis examined eye muscle coordination and focussing in OK contact lens wear; outcomes were consistent with a lower myopia progression risk and improved visual comfort compared to standard spectacles and soft contact lenses. These findings have relevance for patient acceptance, clinical management protocols and understanding OK's optical impact on the visual system of the young myope.

Purpose. The technique of orthokeratology (ortho-k) produces corneal changes as a result of the exerted pressure by the rigid contact lenses. This study aims at gaining a better understanding of the corneal changes produced in ortho-k treatment after the first night of contact lens wear. Methods. Fifteen subjects (fifteen eyes) worn CRT Paragon lenses for one night. The following day corneal curvature and corneal thickness was measured in different moments at the same predefined coordinates (after lens removal, and 3, 6 and 9 hours afterwards) with the Pentacam topographer. Results. A sample of 10 women and 5 men with a mean age of 26.10±3.15 and 22.40±1.43 years, respectively, participated in the study. In corneal curvature, anterior and posterior, no statistical differences were found. In contrast, in pachymetry a trend was observed showing the greatest difference between the baseline measure and the first measure after ortho-k lenses use. Conclusions. Corneal thickness changed with one night of ortho-k treatment. Corneal curvature does not show statistical differences. A larger sample is needed to obtain sounder conclusions given the high inter-subject variability of the results.

There is an epidemic of myopia in East and Southeast Asia, with the prevalence of myopia in young adults around 80-90%, and an accompanying high prevalence of high myopia in young adults (10-20%). This may foreshadow an increase in low vision and blindness due to pathological myopia. These two epidemics are linked, since the increasingly early onset of myopia, combined with high progression rates, naturally generates an epidemic of high myopia, with high prevalences of "acquired" high myopia appearing around the age of 11-13. The major risk factors identified are intensive education, and limited time outdoors. The localization of the epidemic appears to be due to the high educational pressures and limited time outdoors in the region, rather than to genetically elevated sensitivity to these factors. Causality has been demonstrated in the case of time outdoors through randomized clinical trials in which increased time outdoors in schools has prevented the onset of myopia. In the case of educational pressures, evidence of causality comes from the high prevalence of myopia and high myopia in Jewish boys attending Orthodox schools in Israel compared to their sisters attending religious schools, and boys and girls attending secular schools. Combining increased time outdoors in schools, to slow the onset of myopia, with clinical methods for slowing myopic progression, should lead to the control of this epidemic, which would otherwise pose a major health challenge. Reforms to the organization of school systems to reduce intense early competition for accelerated learning pathways may also be important.

Orthokeratology has had a great boom in the last few years, due to the appearance of new materials and designs that have facilitated its application. For this reason, the study proposed to develop a review that would allow to analyze this technique based on the experience of patients who were treated with it. Objectives: To present scientific evidence of the use of orthokeratology for myopia control. Materials and methods: A bibliometric review of 50 scientific articles written between 1999 and 2015, with grade of recommendation B and level of evidence II−3, according to the United States Preventive Services Task Force (USPSTF) scale. The variables age, refractive defect, axial length and corneal curvature were considered. Results: 47% of the patients were younger than 15 years of age. The most important modifications through orthokeratology were found in patients with refractive values lower than −4.00 D (80%); one month after treatment, reductions of an average of −3.11 D were evidenced. The lenses used in the study mainly had an inverse geometry design, with materials with permeability greater than 100. Conclusions: Orthokeratology retards the progression of myopia; this is evidenced in 100% of the articles analyzed. There is a greater efficacy in the control of low myopia (myopia up to 4 D, according to Borish): 55% of patients with myopia from −0.25 to −1.00 D, while the remaining 45% is distributed between −1.25 and −7.00 D., La ortoqueratología ha tenido un gran auge en los últimos años, debido a la aparición de nuevos materiales y diseños que han facilitado su aplicación; por esta razón, se planteó desarrollar una revisión que permitiera analizarla desde aquellos pacientes en quienes se ha usado. Objetivos: mostrar la evidencia científica del uso de la ortoqueratología para el control de la miopía. Materiales y métodos: revisión bibliométrica de 50 artículos científicos escritos entre 1999 y 2015, con grado de recomendación B y nivel de evidencia II-3, según la escala United States Preventive Services Task Force (USPTS). Se consideraron las variables edad, defecto refractivo, longitud axial y curvatura corneal. Resultados: el 47 % de los pacientes eran menores de 15 años de edad. Las modificaciones más importantes a través de la ortoqueratología se encontraron en pacientes con valores refractivos menores de −4,00 D (80 %); al mes de tratamiento se presentaron reducciones en promedio de −3,11 D. En su mayoría, el diseño de los lentes utilizados fue de geometría inversa, con materiales con permeabilidad mayor a 100. Conclusiones: la ortoqueratología retarda la progresión de la miopía; esto se evidencia en el 100 % de los artículos analizados. Hay mayor eficacia en el control de la miopía en valores bajos (miopías de hasta 4 D, según Borish): un 55 % con miopías de −0,25 a −1,00 D, mientras que el 45 % restante se reparte con poderes entre −1,25 y −7,00 D.

Presbyopia is defined as an impairment in near vision, limitating the residual accommodation, hence losing the ability to focus on neal objects. Throughout the world, uncorrected presbyopia causes common, avoidable vision impairment. When the symptoms are established, on a 55 to 60-year-old average, artificial assistance for comfortable close-up tasks is needed. The aim of the study is to investigate the efficacy of a new presbyopic orthokeratology lens design, on a 4-week perios of presbyopic orthokeratology overnight wear. Eighteen presbyopic new orthokeratology wearers, were reviwed. Only seven participants contributed to complete data. A double reservoir lens for presbyopia design with two with different back optical zone diameters was evaluated. Uncorrected distance and near visual acuity, subjective refraction, contrast sensitivity, defocus curve, corneal topography, corneal aberrations and anterior segment health examination were measured at baseline, and compared after a 4-week overnight wear, with designs of 1.9 and 3.0mm back optical zone diameters. Both double reservoir lenses for presbyopia, revealed statistically significant changes. The 1.9mm lens almost corrected distance ametropia, while 3.0mm lens induced a slight myopia, in contraposition, 3.0mm corrected near ametropia by decreasing a 50.55% of the near addition on average. Binocular distance vision remained equal, but uncorrected visual acuities improved after both lenses were used. Induced corneal aberrometries lead to a contrast sensitivity descrease in medium and high frequencies. As a conclusion we can say that double reservoir lenses for presbyopia provide functional near vision by inducing a “center near” myopic shift. Eventhought corneal aberrations were induced, it did not alter binocular visual acuities.

Received 22 December 2014, Revised 2 June 2015, Accepted 30 June 2015, Available online 15 July 2015., Purpose: To describe the stabilization of early adult-onset myopia in three university students after initiating orthokeratology treatment with corneal refractive therapy contact lenses. Methods: Three Caucasian early adult-onset progressing myopic subjects (1 male, 2 females) were fitted with corneal refractive therapy lenses to correct myopia between −1.50 and −2.50 D of sphere using Paragon CRT (Paragon Vision Sciences, Mesa, AZ) lenses for overnight orthokeratology. The pre-treatment refractive history from 2005 as well as refraction and axial length after treatment onset are reported over a period of 3 years between December 2009 and January 2013 with an additional year of follow-up after treatment discontinuation (January–December 2013). The peripheral refractive patterns and topographic changes are also reported individually. Results: Treatment was successful in all three subjects achieving uncorrected visual acuity of 20/20 or better monocularly. During a period of 3 years of follow-up the subjects did not experience progression in their refractive error, nor in their axial length (measured during the last 2 years of treatment and 1 year after discontinuation). Furthermore, the subjects recovered to their baseline refraction and did not progressed further over the following year after lens wear discontinuation. Conclusions: We cannot attribute a causative effect to the orthokeratology treatment alone as underlying mechanism for myopia stabilization in this 3 patients. However, the present report points to the possibility of stabilization of early adult-onset myopia progression in young adults using corneal refractive therapy treatment., FEDER. COMPETE Program, Portuguese Foundation for Science and Technology (FCT), Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Received 31 October 2013; revised 16 December 2014; accepted 13 January 2015; published online 17 March 2015, Purpose: The purpose of this study was to evaluate the effect of orthokeratology for different degrees of myopia correction in the relative location of tangential (FT) and sagittal (FS) power errors across the central 70° of the visual field in the horizontal meridian. Methods: Thirty-four right eyes of 34 patients with a mean age of 25.2 ± 6.4 years were fitted with Paragon CRT (Mesa, AZ) rigid gas permeable contact lenses to treat myopia (−2.15 ± 1.26D, range: −0.88 to −5.25D). Axial and peripheral refraction were measured along the central 70° of the horizontal visual field with the Grand Seiko WAM5500 open-field auto-refractor. Spherical equivalent (M), as well as tangential (FT) and sagittal power errors (FS) were obtained. Analysis was stratified in three groups according to baseline spherical equivalent: Group 1 [MBaseline = −0.88 to −1.50D; n = 11], Group 2 [MBaseline = −1.51 to −2.49D; n = 11], and Group 3 [MBaseline = −2.50 to −5.25D; n = 12]. Results: Spherical equivalent was significantly more myopic after treatment beyond the central 40° of the visual field (p < 0.001). FT became significantly more myopic for all groups in the nasal and temporal retina with 25° (p ≤ 0.017), 30° (p ≤ 0.007) and 35° (p ≤ 0.004) of eye rotation. Myopic change in FS was less consistent, achieving only statistical significance for all groups at 35° in the nasal and temporal retina (p ≤ 0.045). Conclusions: Orthokeratology changes significantly FT in the myopic direction beyond the central 40° of the visual field for all degrees of myopia. Changes induced by orthokeratology in relative peripheral M, FT and FS with 35° of eye rotation were significantly correlated with axial myopia at baseline., Fundação para Ciência e Tecnologia do Portugal, Depto. de Optometría y Visión, Fac. de Óptica y Optometría, TRUE, pub

Orthokeratology is a subspecialty of contact lens research, dealing with the adaptation of gas permeable contact lenses, whose aim is to temporarily reduce visual defects. It proved to be an effective treatment for myopia and low astigmatisms, as well as for hypermetropic errors. This article presents a literature review in databases and books that describe and analyze the advances on how orthokeratology lenses work on the ocular surface of hypermetropic patients over time, on orthokeratology designs in hypermetropia, as well as on the parameters for the efficacy of this procedure, and its contraindications and risks. Thus, it provides further information for visual and ocular health professionals on the importance of orthokeratology in hypermetropic errors as a method of correction, as well as on other approaches that can meet the visual needs of patients., La ortoqueratología es una subespecialidad de la contactología por la que se adaptan lentes de contacto gaspermeables, que tiene como objeto la reducción temporal de los defectos visuales; se ha demostrado que es un tratamiento eficaz para miopías y bajos astigmatismos, así como para defectos hipermetrópicos. Este artículo es una revisión bibliográfica de bases de datos y libros que describen y analizan los avances del funcionamiento de los lentes de ortoqueratología en la superficie ocular de hipermétropes a través del tiempo, los diseños de ortoqueratología en hipermetropía, los parámetros para la eficacia de este procedimiento y sus contraindicaciones y riesgos; de esta manera, se brinda al profesional de la salud visual y ocular información para profundizar sobre la importancia de la ortoqueratología en hipermétropes como método de corrección y otros enfoques que puedan satisfacer las necesidades visuales del paciente.