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Abstract Background To evaluate the long-term effectiveness of orthokeratology (ortho-K) lenses with small treatment zone (STZ) or conventional treatment zone (CTZ) in controlling axial elongation in children with myopia as well as the impact on visual quality. We also sought to determine the effect of retinal visual signal quality on axial elongation. Methods This is a prospective randomized controlled study. A total of 140 participants (age ranging from 8 to 12 years) were randomly assigned to wear either STZ or CTZ ortho-K lenses. STZ ortho-K lenses design was achieved by changing the depth of reverse zone and the sagitta height of the optical zone. Using the IOL-Master 500, axial length (AL) was measured at baseline and after 6, 12 and 18 months of ortho-K treatment. Spherical aberration (SA) and corneal topographic parameters were obtained by the Pentacam anterior segment analyzer at baseline and the 1-month follow-up visit, and optical qualities were assessed by optical quality analysis system-II (OQAS-II) at baseline and after 1 month of lens wearing. Optical quality parameters mainly included the modulation transfer function (MTF) cutoff, Strehl ratio (SR), objective scattering index (OSI), and predicted visual acuity (PVA). Results A total of 131 participants completed the study, including 68 in the STZ group and 63 in the CTZ group. The STZ group had significantly reduced AL elongation compared to the CTZ group after treatment (12 months: 0.07 ± 0.11 mm vs. 0.14 ± 0.12 mm, P = 0.002; 18 months: 0.17 ± 0.15 mm vs. 0.26 ± 0.16 mm, P = 0.002). The topography in the STZ group showed a smaller treatment zone (TZ) diameter (2.50 ± 0.23 mm vs. 2.77 ± 0.18 mm, P

Objective: To observe the effectiveness and safety of long-term wearing of orthokeratology lens in adolescent myopia patients. Methods: From June 2019 to April 2023, 30 myopic adolescents (60 eyes) who had been fitted with orthokeratology lens in the ophthalmology department of Xuanwu hospital and had worn them for a long time (≥ 3 years) were reviewed. They were reexamined 1 day, 7 days, 1 month and 3 month after wearing the glasses. The changes of the axial length and the parameters of corneal endothelioscopy were compared before and after wearing the glasses for 6 months, 1 year, 2 years and 3 years. Result: A total of 30 cases (60 eyes) were observed in this study, including 13 males and 17 females, aged 7-14 years old, with an average age of 9.77 ± 1.89 years old. The equivalent spherical scope was -5.00-0.75D, with an average of -1.98± 0.97 D. Among them, 5 cases (8 eyes, 13.3%) developed grade 1 corneal staining, but no grade 2-3 staining was observed. 2 cases (4 eyes, 6.7%) developed allergic conjunctivitis, which was cured after stopping wearing and receiving corresponding treatment. The axial lengths of 6 mon, 1 a, 2 a, and 3 a before and after wearing glasses were 24.57± 0.74 mm, 24.67± 0.85 mm, 24.78± 0.96 mm, 24.91± 0.97 mm, and 25.06± 0.85 mm, respectively, showing an overall increasing trend (F=21.904, P<0.001). There were statistically significant differences in axial lengths between pre and post wearing glasses at various time points, with P values of 0.027, 0.001, 0.000, and 0.000, respectively. There was a statistically significant difference between 6 mon after wearing glasses and 1 a, 2 a, and 3 a after wearing glasses. The P-values were 0.005, 0.000, and 0.008, respectively. There was a statistically significant difference (P<0.001) between 1 year after wearing the mirror and 2 years after wearing the mirror, while there was no statistically significant difference (P>0.05) between other time points. The coefficient of variation of cell area at 6 mon, 1 a, 2 a, and 3 a before and after wearing glasses were 25± 2.9%, 26± 3.7%, 27± 4.1%, 27± 4.6%, and 27± 4.1%, respectively. Overall, F=5.490, P=0.001. Comparing the two groups, it was found that there was a statistically significant difference between the two groups, with P values of 0.012 and 0.008, respectively (P<0.05). The difference between the two groups was statistically significant (P=0. 007), There was no statistically significant difference between other time points (P>0.05). There was no statistically significant difference in corneal thickness, endothelial cell density, average area, and hexagonal cell ratio at each time point (P>0.05).Conclusion: Adolescent myopia patients can effectively control the rapid growth of their eye axis by wearing corneal reshaping lenses for a long time. However, comprehensive examination and evaluation must be conducted, qualified and appropriately sized lenses must be worn, standardized operations must be carried out, and follow-up visits must be made on time. If allergies or corneal injuries occur, timely cessation of wearing and corresponding treatment can ensure the safety of long-term wearing. Morphological examination of corneal cells revealed that long-term wearing of glasses showed an increasing trend in the variation of corneal endothelial cell area. [ABSTRACT FROM AUTHOR]

Purposes The corneal shape and mechanical properties of cornea and contact lens material have a certain impact on the correction effect of contact lens. Methods In this paper, a finite element model of corneal wearing orthokeratology lens was established by using hyperelasticity materials, and the biomechanical response of cornea after wearing lens was analyzed by changing the shape of cornea (different curvature and thickness) and the material parameters of cornea and orthokeratology lens. Findings The results showed that when the corneal curvature changed 4 m−1, the displacement difference at apex of the cornea central area changed by 15.7 μm, and when the corneal thickness changed by 75 μm, the displacement difference at apex of the central area changed by 12.3 μm; when the corneal material parameter k1 increased by 3 times, the change of displacement difference at apex of the cornea central area was 39.2 μm, when the C10 value increased by 4 times, the change of displacement difference was 55.5 μm, while when the orthokeratology lens material parameter E increased by 3 times, the change of displacement difference was only 0.2 μm. Conclusions When using orthokeratology lens to correct myopia, it is necessary to fully consider the influence of corneal morphology and the mechanical properties of the cornea on the correction effect.

AIM: To observe and analyze the effectiveness and safety of wearing corneal refractive therapy(CRT)and vision shaping treatment(VST)designed orthokeratology in controlling myopic progression in adolescents with low E-value corneal morphology.METHODS: This prospective study involved 100 cases(100 eyes)of adolescent myopia patients fitted with orthokeratology at our optometry clinic from January 2020 to December 2021. The data of right eye were collected for research, and they were divided into low myopia group(-1.00 to -3.00 D)and moderate myopia group(-3.25 to -5.00 D)according to spherical equivalent, with 50 cases in each group. Each group of patients was further randomly divided into the CRT group and the VST group, with 25 cases in each group. Uncorrected visual acuity, refractive error, axial length(AL), tear film break-up time(BUT), corneal endothelial cell density, corneal staining grading, lens decentration, and refractive power at 15°-30° were measured before and after wearing orthokeratology, with a follow-up duration of 1.5 a.RESULTS: The uncorrected visual acuity of CRT and VST subgroups in the low myopia group showed no statistical significance at any time point after wearing orthokeratology. However, in the moderate myopia group, CRT subgroup showed better uncorrected visual acuity than the VST subgroup, with significant differences at 1 d and 1 wk(t=-9.474, -12.067, both P

Myopia has become an important public health problem worldwide. In recent years, more and more researchers have begun to pay attention to peripheral refraction, which plays an important role in ocular development. Emmetropia and hyperopia has myopic defocus in the peripheral retinal, while myopia has hyperopic defocus. Therefore, the conversion of hyperopic defocus in peripheral retina to myopia defocus can slow the progression of myopia. This article mainly updates the relationship of peripheral refraction and myopia. [ABSTRACT FROM AUTHOR]

AIM: To observe the effectiveness, safety and ethnic differences of 0.005% atropine eye drops combined with orthokeratology in controlling adolescents' low myopia between different ethnic groups.METHODS:A total of 246 Han and Hani patients(246 eyes)with low myopia treated in our hospital from January to October 2021 were selected, with 120 patients(120 eyes)treated with 0.005% atropine eye drops combined with orthokeratology in experimental group, and 126 patients(126 eyes)treated with orthokeratology in control group. The uncorrected visual acuity, spherical equivalent(SE), axial length(AL), intraocular pressure, tear film break-up time(BUT), corneal curvature and corneal thickness of the two groups before and 1 a after wearing lenses were observed, and the incidence of complications were recorded.RESULTS:At 1 a after wearing lenses, the changes of AL and SE in the experimental group(0.16±0.35 mm, -0.39±0.47 D)were lower than those in the control group(0.22±0.89 mm, -0.48±0.54 D), uncorrected visual acuity(LogMAR)was better than the control group(0.11±0.25 vs 0.14±0.19; P0.05). In the Han and Hani groups, there were no differences in the changes of uncorrected visual acuity, AL and SE(P>0.05). During the follow-up period, no significant local or systemic adverse reactions occurred in the two groups, and there was no difference in the incidence of ocular complications between the two groups of patients(P>0.05).CONCLUSION: The 0.005% atropine eye drops combined with orthokeratology can effectively delay the progression of low myopia in adolescents without significant adverse reactions and ethnic differences.

As a highly prevalent global condition, myopia significantly impacts the ocular health of young individuals in China. Orthokeratology lens, as a rigid corneal contact lens, has demonstrated effective control over the progression of myopia; however, its mechanism of action remains incompletely elucidated. As one of the factors influencing visual acuity, higher-order aberrations will undergo marked changes after orthokeratology, with particular emphasis on the alterations in spherical aberrations and coma. The changes in corneal morphology induced by orthokeratology lead to significant positive increase in both spherical aberration and coma. Furthermore, the elevation of spherical aberration and coma demonstrates a negative correlation with the rate of axial length growth following orthokeratology. The interplay among spherical aberration, coma, defocus, accommodation, astigmatism, and pseudo-accommodation may constitute the underlying mechanism governing the control of myopia through orthokeratology.

AIM: To investigate the effect of peripheral defocus spectacles and orthokeratology lenses on the control of axial length in children and adolescents with myopia.METHODS: Prospective study. A total of 71 cases(134 eyes)of children and adolescents with myopia who visited the Second Hospital of Longyan from June 2019 to June 2021 were selected. They were fitted with peripheral defocus spectacles for 12mo and then switched to orthokeratology lenses. The growth of axial length was observed at 3, 6, and 12mo after wearing peripheral defocus spectacles and orthokeratology lenses.RESULTS: The median axial length growth after wearing peripheral defocus spectacles and orthokeratology lenses for 12mo was 0.35 and 0.14mm, respectively. The axial growth at 3, 6, and 12mo after wearing orthokeratology lenses was lower than those after wearing peripheral defocus spectacles(P0.05). In the non-rapid progression group, axial growth of cases aged 7-12 years was higher than those aged 13-16 years(P0.05).CONCLUSION: Orthokeratology lens is more effective than peripheral defocus spectacles in controlling axial growth in children and adolescents with myopia, and the control effect of orthokeratology lens on rapid-progressing myopia is remarkable.

AIM: To investigate the effect of wearing an orthokeratology lens on postoperative binocular vision rebuilding in patients with intermittent exotropia combined with myopic refractive error.METHODS: Prospective control study. A total of 60 patients(120 eyes)with intermittent exotropia and myopia who underwent surgical treatment in our hospital from June 2019 to December 2020 were selected. Patients who wore orthokeratology lenses or monofocal frame glasses after surgery were divided into a treatment group(group A)and a control group(group B)according to the wishes of patients and their families, with 30 cases(60 eyes)in each group, and they were followed-up for 6mo. The third level visual function and Titmus near stereoscopic visual function of the two groups of patients were observed before and 6mo after surgery.RESULTS: There was no statistical significance in all observation indicators between group A and group B before surgery(P>0.05). After 6mo of surgery, patients with intermittent exotropia achieved significant improvement in binocular visual function and corrected eye position. Group A was superior to group B in terms of fusion range and near stereoscopic visual function(P0.05).CONCLUSION: The binocular visual function of patients with intermittent exotropia after surgery has significantly improved. Wearing orthokeratology lenses can effectively improve binocular visual function in patients with intermittent exotropia combined with myopia after surgery.

AIM: To investigate the bacterial flora and antibiotic susceptibility testing of conjunctival sac in adolescents after wearing orthokeratology(OK)lens.METHODS:A total of 101 adolescents aged 8 to 14 who admitted to outpatient department of Xi'an No.1 Hospital from September 2021 to August 2022 were recruited in this cross-sectional observational study. There were 51 cases wearing OK Lens(wearing group)and 50 patients not wearing contact lens(non-lens group), the right eye of all patients was selected into the group. The culture of bacterial flora in conjunctival sac between the two groups were compared, the species were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and the antibiotic susceptibility testing was carried out for the positive strains cultured in the wearing group.RESULTS:The positive rate of conjunctival sac bacterial cultured in the wearing group and the non-lens group was 68.6%(35/51)and 60.0%(30/50), respectively(P>0.05). In both groups, the bacteria with the highest detection rate were staphylococcus epidermidis and staphylococcus aureus. The sensitivity rates of the strains detected in the wearing group to drugs are as follows: Levofloxacin(98%), Moxifloxacin(98%), Gatifloxacin(98%), Cefuroxime(98%), Cefathiamidine(98%), Rifampicin(98%), Chloramphenicol(96%), Cefoxitin(95%), Clindamycin(80%), Gentamicin(74%), Fusidic acid(72%), Tobramycin(64%), Compound sulfamethoxazole(26%), Mezlocillin(10%), Azithromycin(6%), of which the sensitivity rate of Gram-positive cocci was 100% sensitive to Vancomycin.CONCLUSION:Gram-positive cocci are the main bacteria isolated from conjunctival sac of adolescents after wearing OK Lens. Wearing OK Lens will not significantly increase the positive rate of conjunctival sac bacterial flora. Results of antibiotic susceptibility testing may provide guidance for empirical medication in patients wearing OK lens after eye infection.

AIM: To investigate the effect of orthokeratology lens on ocular surface and meibomian gland in children and adolescents of different ages.METHODS: A total of 120 cases(240 eyes)of myopic children and adolescents treated in the optometry clinic of our hospital from December 2020 to February 2021 were retrospectively selected, and they were divided into the orthokeratology group(60 cases, 120 eyes)and the frame glasses group(60 cases, 120 eyes)according to the myopia correction methods. The changes in ocular surface and meibomian gland after wearing glasses were analyzed, and those changes in patients of different ages were compared between the two groups.RESULTS: Corneal curvature decreased, non-invasive tear film break-up time(NIBUT)shortened and meibomian gland score increased at 3, 6, 9 and 12mo in the orthokeratology group after wearing lens, while lower tear meniscus height increased at 6, 9 and 12mo compared with that before wearing lens. In the frame glasses group, the lower tear meniscus height was higher at 6 and 9mo than that before wearing glasses(both P

PurposeThe current study designed a unique type of corneal topography evaluation method based on deep learning and traditional image processing algorithms. The type of corneal topography of patients was evaluated through the segmentation of important medical zones and the calculation of relevant medical indicators of orthokeratology (OK) lenses.MethodsThe clinical data of 1,302 myopic subjects was collected retrospectively. A series of neural network-based U-Net was used to segment the pupil and the treatment zone in the corneal topography, and the decentration, effective defocusing contact range, and other indicators were calculated according to the image processing algorithm. The type of corneal topography was evaluated according to the evaluation criteria given by the optometrist. Finally, the method described in this article was used to evaluate the type of corneal topography and compare it with the type classified by the optometrist.ResultsWhen the important medical zones in the corneal topography were segmented, the precision and recall of the treatment zone reached 0.9587 and 0.9459, respectively, and the precision and recall of the pupil reached 0.9771 and 0.9712. Finally, the method described in this article was used to evaluate the type of corneal topography. When the reviewed findings based on deep learning and image processing algorithms were compared to the type of corneal topography marked by the professional optometrist, they demonstrated high accuracy with more than 98%.ConclusionThe current study provided an effective and accurate deep learning algorithm to evaluate the type of corneal topography. The deep learning algorithm played an auxiliary role in the OK lens fitting, which could help optometrists select the parameters of OK lenses effectively.

Purpose: To compare the effect of orthokeratology (ortho‐k) using aspheric or spherical base curve (BCA vs. BCS) contact lenses on axial elongation and the relative peripheral refraction change (RPRC) in Chinese children. Methods: Children aged 8–12 years with myopia between −0.75 and −4.00 D and astigmatism ≤1.00 D were randomly assigned to the BCA or BCS group. Peripheral refraction was assessed at 10°, 20° and 30° along the temporal and nasal retina at baseline and at the 12‐month visit. Axial length (AL) was measured under cycloplegia at baseline and at the 6‐ and 12‐month visits. Only right eye data were analysed. Repeated‐measures analysis of covariance was performed to examine the differences in axial elongation and the RPRC between the BCA and BCS groups. Results: The 1‐year results from 31 BCA and 32 BCS subjects were analysed. No significant between‐group differences were found at baseline (p ≥ 0.28). At the 12‐month visit, the BCA lens produced a greater absolute RPRC along the horizontal meridian than the BCS lens (p < 0.001). Axial elongation was slower in the BCA group (0.19 ± 0.20 mm) than in the BCS group (0.29 ± 0.14 mm; p = 0.03). Axial elongation was correlated with the RPRC at 10° (r = 0.43, p = 0.02) and 20° (r = 0.39, p = 0.03) along the temporal retina in the BCA group; however, these correlations were not observed in the BCS group. Conclusion: The BCA ortho‐k lens could improve the efficacy of slowing axial elongation in children. The improved myopia control observed in the BCA group may be the result of a larger myopic shift in relative peripheral refraction within 20° along the temporal retina. [ABSTRACT FROM AUTHOR]

Purpose: In order to improve the efficiency of orthokeratology (OK) lens fitting and predict the axial length after 1 year of OK lens wear, machine learning models were proposed. Methods: Clinical data from 1302 myopic subjects were collected retrospectively, and two machine learning models were implemented. Demographic and corneal topographic data were collected as input variables. The output variables were the parameters of the OK lens and the axial length after 1 year. Eighty percent of input variables was used as the training set and the remaining 20% was used as the validation set. The first alignment curve (AC1) of the OK lenses, deduced using machine learning models and formula calculation, were compared. Multiple regression models (support vector machine, Gaussian process, decision tree and random forest) were used to predict the axial length after 1 year. In addition, we classified data based on lens brand, and carried out more detailed parameter fitting and analysis for spherical and toric OK lenses. Results: The OK lens fitting model showed higher (R2 = 0.93) and lower errors (mean absolute error [MAE] = 0.19, mean square error [MSE] = 0.09) when predicting AC1, compared with the formula calculation (R2 = 0.66, MAE = 0.44, MSE = 0.25). The machine learning model still had high R2 values ranging from 0.91 to 0.96 when considering the brand and design of the OK lenses. Further, the R2 value for the axial length prediction model was 0.94, which indicated that the machine learning model had high accuracy and good robustness. Conclusion: The OK lens fitting model and the axial length prediction model played an important role in guiding OK lens fitting, with high accuracy and robustness in prediction performance. [ABSTRACT FROM AUTHOR]

Orthokeratology (OK) is becoming a mainstream modality for myopia correction and control, but its underlying mechanism is not yet fully understood. In this study, the biomechanical response of cornea under the OK lens was investigated to further understand the mechanism of OK therapy. Numerical models of the cornea and OK lens with different corneal refractive powers and myopia degrees were established to analyze features and differences of the spatial displacement and stress distribution in different areas of the anterior corneal surface by finite element method. Displacement distributions on the anterior cornea surface with refractive powers of 39.5, 43, 46 D, and myopia degrees of −1.0, −3.0, −6.0 D demonstrate similar deformation trends and nearly rotationally symmetrical attributes of different corneal parameters. Displacement of mid‐peripheral cornea was significantly high compared with that of the central and peripheral cornea, peaking at ~2.4 mm off the corneal apex. The stress increased with the increase in myopia degrees and was significantly large for the myopia degrees of −6.0 D at S1; the stress at S2 and S6 was low and stable and did not differ much at S3; the stress at S4 and S5, however, was extremely high. In summary, simulation result of orthokeratology can effectively evaluate the performance of OK lens and it properly associates with the differential map of the corneal topography. The base curve of the OK lens may also play a role in mid‐peripheral corneal steepening. The design around the OK lens' alignment curve needs to be optimized. [ABSTRACT FROM AUTHOR]

AIM: To investigate the influence of the duration of orthokeratology lens cessation on patients' refractive status and corneal endothelial cells.METHODS: Adolescent myopia patients who wore orthokeratology lens from July 2019 to July 2020 and recently planned to stop wearing the lens were divided into mild group and severe group according to spherical equivalent. Refractive status, corneal morphology, corneal endothelial cells, and visual quality were measured at cessation and 1, 2 and 3mo after cessation.RESULTS: The corneal flat K values, steep K values and mean K values in the two groups were lower at cessation than those before wearing lenses. These values returned to the level before wearing lenses at 2mo after cessation(P>0.05). The corneal astigmatism, surface regularity index and surface asymmetry index in each group showed no statistically significant difference before wearing lenses and at 1, 2 and 3mo after cessation(P>0.05). There was no significant change in corneal endothelial cell density of the two groups at 1, 2 and 3mo after cessation compared with those before wearing lenses(P>0.05). The proportion of hexagonal cells in the two groups was lower at cessation than that before wearing lenses, and it returned to the level before wearing lenses at 1mo after cessation(P>0.05).CONCLUSION: Corneal morphology and corneal endothelial cells can be restored to the level before wearing orthokeratology lens at 3mo after cessation.

AIM: To evaluate the clinical efficacy of wearing base curve aspheric orthokeratology(OK)lens in the control of myopia.METHODS: A prospective study was conducted. A total of 94 cases(94 eyes)of myopia aged 8～13 years old who were fitted with orthokeratology(OK)lens in our hospital from January 2020 to July 2021 were selected(for patients who received OK lens in one eye, the eye is selected as the observation eye, and for patients who receive OK lens in both eyes, the right eye is used as the observation eye). Patients were divided into two groups according to the design of the OK lens, with 46 cases wearing base curve aspheric OK lens in study group and 48 cases wearing base curve spheric OK lens in control group. The study group and the control group were further divided into low myopia group(-3.00D< SE ≤-0.75D)and moderate myopia group(-6.00D< SE ≤-3.00D)according to the baseline spherical equivalent(SE), with 52 cases(52 eyes)in the low myopia group and 42 cases(42 eyes)in the moderate myopia group. Uncorrected visual acuity(UCVA)was evaluated at 1d, 1wk, 1, 3, 6 and 9mo after wearing lenses, and axial length were measured at 6mo and 1a after wearing lenses respectively.RESULTS: All patients completed follow-up, and there was no significant differences in UCVA(LogMAR)between the study group(-0.12±0.08)and the control group(-0.17±0.07)after wearing the OK lens for 1mo(P>0.05); the mean axial length elongation between the two groups had no significant differences after wearing lenses for 6mo and 1a(all P>0.05). In the low myopia group, the axial length elongation of the study group was 0.19±0.17mm after wearing OK lens for 1a, which was significantly lower than that of the control group(0.31±0.18mm; P0.05). There was no significant differences in axial length elongation between the low myopia group and the moderate myopia group in study group after wearing lenses for 6mo and 1a(P>0.05), while there was differences in axial length elongation between low myopia group and moderate myopia group in the control group after wearing lenses for 6mo(0.15±0.13 vs. 0.05±0.12mm)and 1a(0.31±0.18 vs. 0.19±0.12mm; all P

The incidence of myopia is gradually on the rise worldwide, which seriously affects the eye health of teenagers and children, causing enormous loss of socioeconomic benefits. As a result, the prevention and control of myopia is crucial and urgent. In recent years, orthokeratology lens have gradually demonstrated its superiority in the field of myopia prevention and control. At present, the principle of controlling the development of myopia by orthokeratology lens is mainly based on the theory of retinal hyperopia optical defocus, which promotes the shift of hyperopic defocus to myopic defocus in myopic patients to curb the growth of the axial length. The effect of controlling the development of myopia is related to various factors, including the total amount of defocusing, pupil diameter, optical zone design, and lens decentration. The widespread use of orthokeratology lenses will effectively reduce the incidence of myopia in teenagers and children. This paper discusses the principle of controlling the development of myopia by the defocus technique of orthokeratology lenses, and the relationship between the amount of defocusing and the position of the defocusing circle and the effect of myopia prevention and control. A specific review was conducted to clarify the research progress on defocus technique of orthokeratology lens in the prevention and control of myopia.

AIM: To compare the progress of binocular myopia with orthokeratology lens in different degrees of unilateral myopia in anisometropic children for 1a.METHODS:Retrospective case-control study. The data of 60 unilateral myopic anisometropia children, 8-12-year-old patients who fitted with orthokeratology lens in Xi'an No.1 Hospital from June 2018 to June 2019 were collected. The binocular spherical equivalent(SE)difference ≥2.5D was found in 30 cases in the high anisometropia group, and 1.0D≤ binocular SE difference

Introduction: To investigate the effects of an orthokeratology lens on the tear film and tarsal glands and myopia control in children with unilateral myopia using an intelligent analysis model.Methods: We retrospectively reviewed the medical records from November 2020 to November 2022 of 68 pediatric patients with unilateral myopia in Fujian Provincial Hospital who had been wearing an orthokeratology lens for more than 1 year. The 68 myopic eyes were included in the treatment group, while the 68 healthy, untreated contralateral eyes were included in the control group. Tear film break-up times (TBUTs) were compared between the two groups at various intervals, and an intelligent analysis model was used to compare the deformation coefficients of 10 meibomian glands in the central area and the different positions of the glands in the two groups after 12 months of treatment. Changes in axial length and equivalent spherical power were also compared between the groups before and after 12 months of treatment.Results: In the treatment group, TBUTs differed significantly between 1 and 12 months after treatment, although no significant differences from baseline were observed at 3 or 6 months. No significant differences in TBUTs were observed at any time point in the control group. After 12 months of treatment, significant between-group differences were observed for glands 2, 3, 4, 5, 6, 7, 8, and 10 (numbered from the temporal to nasal regions). The treatment group also exhibited significant differences in deformation coefficients at different detection positions in the central region, with glands 5 and 6 exhibiting the highest deformation coefficients. Increases in axial length and equivalent spherical power were significantly greater in the control group than in the treatment group after 12 months of treatment.Discussion: Wearing orthokeratology lenses at night can effectively control myopia progression in children with unilateral myopia. However, long-term use of these lenses may lead to meibomian gland deformation and impact tear film function, and the extent of deformation may vary at different positions in the central region.

Myopic anisometropia is a special type of refractive error. As the prevalence of myopia has rapidly increased worldwide in recent years, the prevalence of myopic anisometropia is also growing year by year. Anisometropia can cause aniseikonia of the retinal and fusion impairment, leading the problems such as asthenopia, monocular suppression, amblyopia, and stereopsis disorder, which results in negative effects on patients' work and life. Therefore, it is crucial for children to discover myopic anisometropia in early stage and take effective measures in time to delay the progression of it. At present, a wide range of research has been conducted to study the methods that control the progression of myopia among children. It has been found that orthokeratology lens(OK lens)can effectively slow the progression of myopic anisometropia. This article mainly reviews the mechanism of how orthokeratology control myopic anisometropia, its effect on delaying the progression of myopic anisometropia, and its impact on stereopsis among children with myopic anisometropia, aiming to provide a theoretical basis for the prevention and control of myopic anisometropia in the future.

AIM: To investigate the effects of long-term orthokeratology lens wearing on corneal morphology, corneal biomechanics and objective visual quality.METHODS: A retrospective study was conducted to collect 33 myopic patients(60 eyes), including 19 males(35 eyes)and 14 females(25 eyes), mean age 11.80±1.51 years old, with an average equivalent spherical lens of -3.25±0.69D, who had been wearing orthokeratology lens for 2a from October 2019 to December 2020 in our hospital. Relevant data were collected before wearing and 2a after wearing. The radius of curvature(ARC and PRC), the thickness of the thinnest cornea(THP)and the index of comprehensive deviation analysis of corneal dilation(BADD)were measured by Pentacam anterior segment analysis system. Corvis ST biomechanical analyzer measured non-contact biomechanical corrected intraocular pressure(blOP), maximum deformation amplitude(DA), maximum reverse radius(HCR), ratio of deformation amplitude between apex and 1mm(DR), hardness parameters(SPA1), and corneal biomechanical parameters(CBI). The biomechanical index(TBI)of CT scan was obtained by the combined diagnosis system of Pentacam and Corvis ST. OQAS-II objective visual quality analysis system measured modulation transfer function cutoff frequency(MTF cutoff), Stryl ratio(SR), objective scattering coefficient(OSI)and OV value(OV100%, OV20% and OV9%). The above parameters were compared before and continuously wearing orthokeratoscope for 2a. RESULTS: After 2a of wearing orthokeratology, ARC increased, THP decreased, and BADD increased(t=-9.38, 2.85, -13.08; all P0.05). DA increased and HCR decreased compared with before wearing orthokeratology lens(t=-2.37, 2.28; all P0.05). SR was higher than before, OV20% and OV9% were lower than before(t=-5.31, 8.37, 2.34; all P0.05).CONCLUSION: Long-term wearing of orthokeratology lens changed the morphology of the anterior corneal surface, but had no significant effect on the corneal biomechanics, and the objective visual quality of patients was improved during the day, but decreased at night.

The adsorption of tear film compositions such as proteins and lipids on the orthokeratology lenses often lead to infection or corneal damage. In order to investigate whether polysaccharides could prevent tear compositions from being adsorbed on the lens, alginic acid and lambda-carrageenan were added into artificial tear solution. By measuring daily adsorption of cholesterol, lysozyme, and albumin, our results showed that polysaccharides could weakly prevent cholesterol adsorption. In addition, polysaccharides could also reduce albumin deposition over time. Although the effect of polysaccharides on lysozyme adsorption was distinct depending on the concentrations of polysaccharides, the overall results demonstrated that polysaccharides could decrease protein deposition over time. Our results provided an in vitro evidence that polysaccharides may be applied as coating materials on the lens or as the composition of artificial tear solutions or eyedrops, in order to prevent adsorption of tear film compositions that may lead to a reduced incidence of infection or corneal damage for orthokeratology lens wearers. [ABSTRACT FROM AUTHOR]

We aimed to investigate the changes in higher-order aberrations (HOAs) after wearing orthokeratology (OK) lenses in myopic patients. The study included 15 eyes from ten myopic patients, whose refractive error was myopia less than −4.5 diopters (D) and astigmatism less than 1.5 D. Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) were measured, and Zywave® aberrometry was performed at baseline and 1, 3, and 6 months following OK lens wear. The mean age was 11.5 years (range: 9–15 years). There was a significant improvement in UCVA (p ≤ 0.001) and a decrease in the spherical equivalent measured with auto-refraction at 6 months (p ≤ 0.001). Total HOAs significantly increased after OK lens wear (p ≤ 0.001), with spherical aberration increasing approximately 3.9-fold (p = 0.05). Spherical aberration demonstrated statistically significant positive correlations with the change in spherical equivalent at 3 and 6 months (p = 0.007 and 0.003, respectively). After wearing properly prescribed OK lens, all subjects had significantly improved UCVA and decreased myopic spherical equivalent, with increased total HOAs and positive spherical aberration at 1 month, and the changes were maintained at 6 months. Serially checked spherical aberration could evaluate the anti-myopia effect of the orthokeratology lens in children. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the efficacy of repeated low-level red-light (RLRL) therapy combined with optical lenses in children and adolescents with myopia., Methods: This retrospective study included 108 children and adolescents. Based on the difference in the combination intervention scheme participants were divided into four groups based on the intervention they received: the RLRL+orthokeratology (OK) lens intervention group (RLRL+OK group), the RLRL+defocus distributed multi-point (DDM) lens intervention group (RLRL+DDM group), the RLRL+single-vision spectacles (SVS) intervention group (RLRL+SVS group), and a control group. Visual acuity, spherical equivalent refraction (SER), and axial length (AL) were measured before and after the intervention. Binary logistic regression was used to identify factors influencing vision recovery., Results: The SER and AL at baseline were statistically different ( P <0.01). After the intervention, the AL increase in the RLRL+OK, RLRL+DDM, and RLRL+SVS groups was significantly better than the control group across time points ( P <0.001). Changes in SER were also statistically significant in the RLRL+DDM and RLRL+SVS groups compared to the control group across time points ( P <0.001). The intervention method was identified as a significant factor influencing vision recovery ( P <0.001)., Conclusion: RLRL therapy combined with optical lenses is effective in controlling myopia progression in children and adolescents., Competing Interests: None., (AJTR Copyright © 2024.)

This literature review describes the effect that orthokeratology lenses render on various eye’s structures. The use of these lenses, in addition to the expected changes can cause undesirable effects. The positive aspects include stopping or slowing the myopia’s progression, as well as a temporary improvement of uncorrected visual acuity by changing the shape of the anterior surface of the cornea. Undesirable moments are a change in the homeostasis of the tear film, epitheliopathy, the lens binding, in addition, there is the appearance of an iron arch, an increase in the visibility of fibrillary lines, a transient change in the biomechanical properties of the cornea. On the positive side, these changes do not affect visual function and eye health; moreover, they are reversible. At the same time, the terms of recovery of various structures of the eye can differ from several weeks to several months, depending on the duration of treatment and the target refraction. Thus, the use of orthokeratology lenses is a safe and effective method for correcting and “controlling” myopia.

AIM: To study the effect of intensive online courses on myopia in primary and middle school students with orthokeratology-lens during Corona Virus Disease 2019(COVID-19)epidemic.METHODS:A total of 77 children in myopia with orthokeratology lens in outpatients from February to August 2020 were included in the study. Take a questionnaire to statistics times spending on online course, school class, playing digital electronic good, outdoor activity, homework, sleeping during the COVID-19 epidemic and school time, and analyze the differences of axial length(AL)variation between the COVID-19 epidemic and school time.RESULTS:For elementary school students, the time spending on online course and school class were 2.69±1.02h and 4.07±0.78h per day respectively(P

AIM:To investigate the monocular and binocular accommodative difference between wearing orthokeratology lens and frame lens in low myopic anisometropia children.METHODS: Totally 47 children(94 eyes)with low degree myopic anisometropia(1.0D≤binocular equivalent spherical lens difference 0.05). The binocular AR difference in group A was significantly higher than group B(0.38±0.36D vs 0.10±0.26D, P=0.005), and the binocular AF was lower(8.22±1.15c/min vs 9.95±0.89c/min, P

AIM:To explore the effect of eccentricity of overnight orthokeratology(OK)lenses on 2-year eye axial growth and visual quality.METHODS:Based on the degree of eccentricity of OK lenses, patients were divided into three groups: a low degree of eccentricity group(degree of eccentricity ≤0.5 mm), a group of moderate eccentricity(eccentric degree >0.5-≤1.0 mm)and a group with a high degree of eccentricity(eccentric degree >1-≤1.5 mm). The degree of eccentricity of the OK lens, spherical equivalent(SE), the uncorrected visual acuity after wearing OK lenses(UCVA), axial length before and after wearing OK lenses(AL), total higher-order aberrations(HOA), comas, and spherical aberrations(SA)for 3 mm pupils were analyzed. The difference among the three groups for all parameters was compared using the Kruskal-Wallis H Rank-Sum test.RESULTS:The study retrospectively analyzed 75 cases(139 eyes). In the low eccentricity group(53 eyes), the mean age was 11.4±2.4 years, SE was -3.24±1.48 D, and AL was 24.85±1.01 mm. In the moderate eccentricity group(53 eyes), the mean age was 11.4±2.2 years, SE was -3.22±1.29 D, and AL was 25.15±0.92 mm. In the high eccentricity group(31 eyes), the mean age was 11.5±1.9 years, SE was -3.54±1.43 D, and AL was 24.95±0.84mm. After two years, there was no significant difference in the changes of the axis among the three groups(P=0.089). The HOA, SA, and coma in the high eccentric group were significantly higher than in the middle eccentric group(PPCONCLUSION:For OK lenses, it is unnecessary to strictly require the absolute centralization of the lens position. An unnecessary change of the lenses may delay the eye-axis control. However, the balance between axial control and visual quality should be assessed.

AIM: To investigate the compliance and the relative influencing factors of orthokeratology lens in the treatment of teenagers' and children's myopia in Dongguan,and provide a scientific basic for prevention and control of myopia.METHODS: Totally 757 patients of teenagers' and children's myopia with orthokeratology lens in our hospital from January 2017 to December 2017 were collected. Data from medical records and return visits by telephone, short message and Wechat were collated and summarized, then grasp the compliance and the relative influencing factors of orthokeratology lens in the treatment of teenagers' and children's myopia in Dongguan by analyzing re-examine time and persistence in wearing lens.RESULTS: Totally 757 patients with mean age at 11.82±2.234 years old, including 363 males, mean aged 11.66±2.256 years old, and 394 females, mean aged 11.96±2.206 years old, there was no significant difference in age comparison of boys and girls(t=-1.855, P>0.05). In terms of re-examination compliance and persistence on wearing lens, significant difference was observed in educational stage, studying way and parents' education level(PP>0.05). Multivariate Logistic regression analysis showed that educational stage, studying way and parents' education level were correlated with re-examination compliance and persistence on wearing lens(PCONCLUSION: Compliance of orthokeratology lens in the treatment of teenagers' and children's myopia in Dongguan was correlated with educational stage, studying way and parents' education level, to improve the compliance of orthokeratology lens in the treatment of teenagers' and children's myopia, Standardize fitting, standardize care, normative propaganda and education, review on time and regular return visits were important.

Purpose: Total deposition and deposition along the reverse curve of heavily deposited worn orthokeratology (OK) lenses were quantitatively evaluated using two novel imaging methods. In addition, the cleaning efficacies of a contact lens cleaning solution for daily use and an intensive cleaner and protein remover solution were evaluated using the same two methods. Study design: Experimental study. Methods: Twenty-six worn reverse-geometry OK lenses (MY Emerald, Technopia) were photographed for use in three experiments: (1) total deposition was assessed before and after cleaning with two cleaning solutions; (2) in addition to assessing total lens deposition, the feasibility of measuring the thickness of lens deposits along the reverse curve was assessed; and (3) after confirming it was possible to assess the thickness of lens deposits, the thickness of deposits was assessed before and after cleaning with a daily contact lens cleaning solution (O2 Care®, Menicon Co., Ltd.) and an intensive cleaner and protein remover (Progent®, Menicon Co., Ltd.). Total lens deposition was assessed as the total volume of cloudiness over the lens surface in terms of volume per unit pixel. Cross-sectional images were taken from worn OK lenses to assess the thickness of lens deposits on the reverse curve as the area of deposits/horizontal length. Results: Significant differences in total deposition were found between the three cleaning conditions for the twenty worn OK lenses (mean total deposition ± SD for pre-cleaning = 0.209 ± 0.076; post-daily cleaning = 0.124 ± 0.078; and post-intensive cleaning = 0.045 ± 0.046) (p < 0.001). Mean total deposition and thickness of the deposits along the reverse curve for the three lenses from the second experiment were 0.310 and 6.0 mm, respectively. The mean thicknesses of lens deposits found in the third experiment under the 3 conditions were as follows: pre-cleaning = 3.4 µm; post-daily cleaning = 2.3 µm; and post-intensive cleaning = 0.0 µm. Conclusion: The two novel imaging methods used in this study detected significant amounts of deposits attached to worn OK lenses and were sensitive enough to detect a reduction in deposition following the use of the two cleaning solutions tested. Furthermore, these methods could visualize and quantify the thickness of lens deposits along the reverse curve. [ABSTRACT FROM AUTHOR]

The adsorption of tear film compositions such as proteins and lipids on the orthokeratology lenses often lead to infection or corneal damage. In order to investigate whether polysaccharides could prevent tear compositions from being adsorbed on the lens, alginic acid and lambda-carrageenan were added into artificial tear solution. By measuring daily adsorption of cholesterol, lysozyme, and albumin, our results showed that polysaccharides could weakly prevent cholesterol adsorption. In addition, polysaccharides could also reduce albumin deposition over time. Although the effect of polysaccharides on lysozyme adsorption was distinct depending on the concentrations of polysaccharides, the overall results demonstrated that polysaccharides could decrease protein deposition over time. Our results provided an in vitro evidence that polysaccharides may be applied as coating materials on the lens or as the composition of artificial tear solutions or eyedrops, in order to prevent adsorption of tear film compositions that may lead to a reduced incidence of infection or corneal damage for orthokeratology lens wearers.

Abstract Background We aimed to investigate the effect of short-term orthokeratology lens or frame glasses wear on corneal thickness, corneal endothelial cells and vision correction in adolescents with low to moderate myopia. Methods Data of 100 adolescents with low to moderate myopia were retrospectively analyzed. The patients were assigned into two groups. The experimental group were treated with night-wear orthokeratology lens, and control group were treated with ordinary frame glasses. Follow up was carried out at the 3rd, 6th and 12th months of treatment. The naked-eye vision, diopter, corneal curvature, intraocular pressure, axial length, endothelial cell count and central corneal thickness were examined. Complications within 12 months were observed, and corneal fluorescein staining was graded. Results The naked-eye vision of the experimental group was significantly higher than that of the control group at the 3rd, 6th and 12th months, while the diopter of the experimental group was significantly lower than that of the control group at these time points. The corneal curvature of the experimental group was significantly decreased when comparing with that of the control group at the above 3 time points. The increase of axial length in the experimental group was significantly less than that in the control group at the 6th and 12th months. Conclusions Short-term orthokeratology lens wear can effectively improve the naked-eye vision in adolescents with low to moderate myopia without significant impact on the central corneal thickness and corneal endothelial cells. It is a relatively safe method to correct myopia.

To investigate the clinical efficacy of frame glasses combined with orthokeratology lens in correction of high myopia in adolescents and its influence on corneal endothelial cells and tear film. 98 cases (181 eyes) adolescent patients with high myopia who were admitted in our hospital from January 2018 to March 2019 were selected, they were divided into control group of 49 cases with 92 eyes (conventional frame glasses wearing treatment)and observation group of 49 cases with 89 eyes (orthokeratology on the basis of the control group) according to envelope drawing method. The uncorrected visual acuity, diopter, axial length, density and quantity of corneal endothelial cells, tear film situation and complications situation were compared between the two groups. The diopter of the observation group decreased after 1 month, 3 months, 6 months, 1 year after treatment (P<0.05), the axial length did not change significantly (P>0.05), and the uncorrected visual acuity increased than those of before treatment, 1 month, 3 months after treatment after 6 months, 1 year of treatment and the uncorrected visual acuity of 1 year after treatment was higher than those of 6 months after treatment P<0.05 . The diopter of 1 month, 3 months, 6 months, 1 year after treatment of the observation group was lower than that of the control group (P<0.05). The uncorrected visual acuity of the observation group at 6 months, 1 year after treatment was higher than those of the control group, and the axial length was shorter than that of the control group (P<0.05). There was no difference in corneal endothelial cell density (ECD), percentage of hexagonal cells (HEX) and coefficient of variation (CV) of cell area between the two groups before treatment, 1 year after treatment (P>0.05). 1 year tear film rupture time (TBUT), non contact tear film rupture time (NTBUT) of the observation group were lower than those of before treatment, and was lower than the control group (P<0.05). There was no difference in basal tear secretion Schirmer before treatment, 1 year after treatment between the two groups (P>0.05). There was no difference in the incidence of complications between the two groups (P>0.05). Frame glasses combined with orthokeratology lens in adolescent high myopia, it can effectively correct the myopia diopter and improve the uncorrected visual acuity, there is no significant effect on corneal endothelial cells, and does not increase the incidence of complications, but it has a certain influence on the stability of human tear film, which is necessary to strengthen the examination of tear film before wearing glasses and follow-up after wearing glasses in clinical treatment [ABSTRACT FROM AUTHOR]

AIM: To observe the effect of orthokeratology on the positive relative accommodation of juvenile with myopia. METHODS: Retrospective analysis of cases. All 122 cases(244 eyes)of juvenile with myopic from September 2016 to December 2017 in our hospital were analyzed. 63 cases were corrected by orthokeratology lens and 59 cases were corrected by glasses. data of the binocular positive relative accommodation before treatment and 6mo after treatment were compared between the two groups. RESULTS:Before treatment, the average PRA value of the orthokeratology group(-0.83±0.23)D and the average PRA value of the glasses group(-0.77±0.24)D were no significant difference(t= -1.457, P>0.05). There was no significant difference between the two groups before treatment in eye axis(orthokeratology group 24.84±0.90mm, glasses group 24.78±0.86mm, t=0.550, P>0.05). PRA in the orthokeratology group -2.27±0.37D was significantly higher than that in the pre-treatment group -0.83±0.23D(t=37.070, Pt=1.565, P>0.05). After treatment, the PRA of orthokeratology group was better than that of glasses group, and the difference was statistically significant(t=-25.271, Pt=-2.453, Pt=39.135, Pt=-0.932,P>0.05). CONCLUSION: The corrected visual acuity of juvenile myopia by orthokeratology was significantly higher than that by using glasses 6mo after treatment, but there was no significant difference between the two groups in eye axis during 6mo.

AIM: To evaluate the clinical effect and safety of orthokeratology for minor to moderate myopia in adolescents.METHODS:Sixty-three adolescent patients with mild to moderate myopia were selected in our hospital from January 2016 to January 2018. Visual acuity, corneal curvature, central corneal thickness, diopter, macular retinal thickness, axial length, intraocular pressure, tear film rupture time, corneal staining and complications were observed before and after wearing glasses for 1wk, 1, 6mo and 1a respectively.RESULTS: There were significant differences in naked vision, diopter, corneal curvature and tear film rupture time before and after wearing glasses in this group(PP>0.05).CONCLUSION: Corneal plastic lens is a safe and effective non-surgical method for myopia correction in adolescents at the stage of growth and development.

Orthokeratology lenses are commonly used for myopia control, especially in children. Tear lipids and proteins are immediately adsorbed when the lens is put on the cornea, and protein deposition may cause discomfort or infection. Therefore, we established an in vitro protein deposition analysis by mimicking the current cleaning methods for orthokeratology lens wearers for both short-term and long-term period. The results showed that the amounts of tear proteins accumulated daily and achieved a balance after 14 days when the lens was rubbed to clean or not. Protein deposition also affected the optical characteristics of the lens regardless of cleaning methods. Our results provided an in vitro analysis for protein deposition on the lens, and they may provide a potential effective method for developing care solutions or methods that can more effectively remove tear components from orthokeratology lenses.

Purpose: To investigate the effect of orthokeratology (OK) lens on axial length (AL) elongation in unilateral myopia and bilateral myopia with anisometropia children.Methods: Twenty-seven unilateral myopia (group 1) and 25 bilateral myopia with anisometropia children (group 2) were involved in this 1-year retrospective study. The eyes with higher spherical equivalent refractive error (SER) were assigned to the H eyes subgroup and the fellow eyes with lower SER to the L eyes subgroup in the two groups.Results: The mean change in AL of H eyes and L eyes were 0.11 ± 0.19 mm, 0.30 ± 0.28 mm in group 1 (P = 0.04) and 0.09± 0.14mm, 0.13± 0.16mm in group 2 (P = 0.36), respectively. Multivariate regression analyses showed that significant difference of change in AL was found between H eyes and L eyes in group1 (β=0.25, P = 0.03), but no difference in group 2 (β=0.09, P = 0.12). The AL of H eyes in group 1 and group 2, H eyes in group 1 and L eyes in group 2 had the same increased rate (β= -0.04, P = 0.43; β = 0.02, P = 0.56).Conclusions: Monocular OK lens is effective on suppression AL elongation of the myopic eyes and reduce anisometropia value in unilateral myopic children. The OK lens can control the AL elongation in both eyes at the same rate, but it cannot reduce anisometropia value in bilateral myopia with anisometropia children after 1-year follow-up. [ABSTRACT FROM AUTHOR]

Objective To observe the effects of different amplitudes of accommodation on the control and safety of orthokeratology in children with mild to moderate myopia. Methods Totally 128 children (128 eyes) with mild to moderate myopia were selected as the study subjects, and all of them wore orthokeratology lens. We calculated the average of the amplitudes of accommodation of all children before wearing orthokeratology lens. According to whether the amplitude range be fore wearing the lens is higher than the average, all the children were divided into two groups, and there 62 cases (62 eyes) in the group A, whose amplitudes of accommodation before wearing the lens was lower than the average, and 66 cases (66 eyes) in the group B, whose amplitudes of accommodation before wearing the lens was higher than the average. The amplitudes of accommodation, the axial length, the corneal endothelial cell density, and corneal endothelial cell area before wearing and at 12 and 24 weeks after wearing were recorded and compared. Pearson correlation analysis was used to analyze the correlation between the amplitudes of accommodation before wearing the lens and the increment in axial length of the eye after 24-month wearing. Results All patients underwent optician and completed follow-up. The amplitudes of accommodation of the two groups wearing lens for 12 and 24 months was significantly higher than that before wearing lens (P <0. 05); the amplitudes of accommodation of group B before wearing the lens and wearing lens for 12 months and 24 months was significantly higher than that of group A (P <0. 05); the increment in amplitudes of accommodation of group A wearing the lens for 24 months was significantly higher than that of group B (P <0. 05); no significant difference was found in the length of the axial length of group A between before wearing lens and wearing lens for 12 months and 24 months (P >0. 05); the axial length of group B before wearing the lens and wearing the lens for 12 and 24 months was significantly higher than that of the group A at the same time (P < 0. 05); the corneal endothelial cell density and corneal endothelial cell area of the two groups had no significant changes as compared with those before wearing, with no significant difference (P >0. 05). Pearson correlation analysis showed that the amplitudes of accommodation of children before wearing the lens was positively correlated with the axial length of children wearing lens for 24 months (r =0. 645, P <0. 05). Conclusion Children with low-amplitudes of accommodation and mild to moderate myopia have an advantage in controlling the length of the axial length of the eye after wearing orthokeratology lens, and the corneal function is not significantly affected, which may be related to improvement of the former's amplitudes of accommodation and the regulation function dominating the development of myopia. [ABSTRACT FROM AUTHOR]

To compare the changes in corneal biomechanics after orthokeratology (OK) lens and Defocus Incorporated Soft Contact (DISC) lens treatment. Of 28 myopic children were recruited, with one eye wearing OK lens and the other eye wearing DISC lens for one year, and the data after discontinued for 4 weeks were also collected. Major outcomes were corneal biomechanics and axial length (AL) elongation. Throughout the follow-up period, the DISC group had longer the first applanation (A1) time, larger A1 deformation amplitude, A1 deflection length (A1 DLL), and A1 deflection amplitude than the OK group. AL elongation was less in the OK group at each visit (all P < 0.05) but faster in the OK group than in the DISC group after discontinuation (P = 0.006). Moreover, AL elongation was related to baseline A1 time, A1 velocity and whole eye movement max in the DISC group, and in the OK group, was related to the baseline the second applanation (A2) DLL, A2 delta arc length and stiffness parameter A1 (all P < 0.05). The cornea was more deformable after wearing DISC lens than OK lens, and corneal biomechanical parameters were associated with AL elongation. Eyes showed less AL elongation during OK lens treatment while faster AL elongation after discontinuation than DISC lens. The baseline corneal biomechanics may help to predict AL elongation in myopic control strategies. [ABSTRACT FROM AUTHOR]

AIM: To analyze the effect of myopic adolescents wearing orthokeratology lens on the corneal surface curvature radius and anterior chamber depth. METHODS: Totally 120 cases of adolescent myopia were selected, among them 58 cases with 116 eyes were divided into 11-14 years old group and 62 cases with 124 eyes were 15-18 years old group according to the age. They were treated with long-term orthokeratology lens treatment, and two groups of patients were observed before wearing lens(T0), wearing for 6mo(T1), 12mo(T2)for uncorrected visual acuity, the average refractive degree improvement, the central corneal thickness, corneal curvature changes and the incidence of complications. RESULTS: The uncorrected visual acuity of the two groups at 12mo after wearing were better than that at 6mo which was better than that before wearing; the diopter had the same trend. The uncorrected visual acuity and the diopter of the 11-14 years old group at 6 and 12mo was better than those of 15-18 years old group with significant difference(PP>0.05). The corneal anterior surface curvature of the two groups at 12mo after wearing were more than that at 6mo which was more than that before wearing. The axial length of the 11-14 years old group was longer than that of the 15-18 years old group with significant difference(PP>0.05). There was no significant difference on the anterior chamber depth between the two groups at different time or between before and after wearing(P>0.05).CONCLUSION: Long-term wearing orthokeratology lenses have a significant effect for control ling juvenile myopia, and can improve the corneal anterior surface curvature, especially in the lower age group, and has no significant effect on the anterior chamber depth.

AIM:To investigate the changes and effects of orthokeratology on corneal morphology. METHODS: Totally 90 patients were treated with orthokeratology from January 2015 to December 2016. They were divided into observation group(overnight wearing)and control group(daytime wearing), 45 cases(90 eyes)in each. The central corneal thickness, corneal curvature,spherical equivalent(SE), uncorrected visual acuity(UCVA)of both groups were compared before and after wearing orthokeratology lens for 1wk, 1, 3, and 6mo.RESULTS: The central corneal thickness of two groups before wearing glasses was significantly higher than that of the cornea after wearing glasses 1wk, 1, 3 and 6mo(all PPP vs 41.3±0.9D, P vs -0.52±0.19D, PPCONCLUSION: Wearing orthokeratology lens can reduce myopia degree. Wearing it overnight has the better outcome than wearing in the daytime.

AIM:To observe the influence of wearing nocturnal orthokeratology lens on sleep quality in myopic patients. METHODS:Totally 30 myopic patients(58 eyes)wearing nocturnal orthokeratology lens, who received medical treatment at the Department of Ophthalmology of Affiliated People's Hospital of Fujian University of Traditional Chinese Medicine, were included in study(treated group). And 30 myopic patients wearing spectacles at the same time were randomly selected as the control group. Sleep quality of two groups were assessed with Pittsburgh sleep quality index(PSQI)before and after wearing the lens in the first and the third months, and compared. RESULTS: Equivalent diopter of the 30 patients wearing nocturnal orthokeratology lens was -2.78D±0.90D before treated with orthokeratology lens, -0.30D±0.31D after 1mo of treatment, and -0.28D±0.30D after 3mo of treatment. There was significant difference between the equivalent diopter got before treated with orthokeratology lens and that got after 1mo of treatment(PPPP>0.05). CONCLUSION: Wearing nocturnal orthokeratology lens has no significant effect on the overall sleep quality index of myopic patients, but the subjective sleep quality decreased in the early stage of wearing the lens.

Purpose: The current study designed a unique type of corneal topography evaluation method based on deep learning and traditional image processing algorithms. The type of corneal topography of patients was evaluated through the segmentation of important medical zones and the calculation of relevant medical indicators of orthokeratology (OK) lenses., Methods: The clinical data of 1,302 myopic subjects was collected retrospectively. A series of neural network-based U-Net was used to segment the pupil and the treatment zone in the corneal topography, and the decentration, effective defocusing contact range, and other indicators were calculated according to the image processing algorithm. The type of corneal topography was evaluated according to the evaluation criteria given by the optometrist. Finally, the method described in this article was used to evaluate the type of corneal topography and compare it with the type classified by the optometrist., Results: When the important medical zones in the corneal topography were segmented, the precision and recall of the treatment zone reached 0.9587 and 0.9459, respectively, and the precision and recall of the pupil reached 0.9771 and 0.9712. Finally, the method described in this article was used to evaluate the type of corneal topography. When the reviewed findings based on deep learning and image processing algorithms were compared to the type of corneal topography marked by the professional optometrist, they demonstrated high accuracy with more than 98%., Conclusion: The current study provided an effective and accurate deep learning algorithm to evaluate the type of corneal topography. The deep learning algorithm played an auxiliary role in the OK lens fitting, which could help optometrists select the parameters of OK lenses effectively., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Xu, Yang, Zhang, Zheng, Zheng, Liu, Zhang, Li and Ye.)

AIM:To evaluate the safety and effectiveness of Orthokeratology in correcting and curing mild and moderate myopia for teenager patients by investigating the clinical response of wearing Orthokeratology at day or night and further analyze the underlying factors. METHODS: Eighty-nine eyes(spherical equivalent refraction≤-6.00D, astigmatism with the rule ≤-1.50D and astigmatism against the rule ≤-0.75D)of 45 teenagers aged between nine and twenty wearing Orthokeratology contact lens from 2012 to 2014 were selected and then randomly divided into two groups, twenty-nine eyes wearing at day and sixty eyes wearing at night. The lens were put on eight to ten hours each time. Uncorrected visual acuity, residual spherical equivalent refraction, central corneal thickness, corneal curvature were examined punctually in addition to checking any kind of eye damage or complication after Orthokeratology at 1wk, 1, 3 and 6mo. RESULTS:Uncorrected visual acuity was markedly corrected while residual spherical equivalent refraction was reduced after one wk contact lens wearing treatment. The above results were of statistical significance(PPP>0.05). Central corneal thickness at one mo had the most obvious change which decreased 7.26±1.38μm(wearing at day)and 15.15±0.50μm(wearing at night)respectively, showing great statistical significance(PCONCLUSION: Orthokeratology can effectively reduce myopic diopter and improve uncorrected visual acuity. However, we still can not neglect the risk and should make sure of the safety by standardizing the optometry process and improving the fitting skills.

AIM: To evaluate the long-term efficiency and safety of overnight orthokeratology in myopia correction and control in adolescents. METHODS: Sixty-five myopia adolescents treated in our hospital from August 2011 to February 2012 were retrospectively analyzed and followed up to 2a. Among them, 35 cases(67 eyes)wearing overnight orthokeatology were included as trial group, and 30 cases(60 eyes)wearing spectacles were included as control group. The trial group were divided into 2 subgroup according the myopic grading in the initial visit: subgroup A(35 eyes, ≤-3.00D), B subgroup(32 eyes,>-3.00D and ≤-6.00D). In the trial group, slit lamp, visual acuity, refraction, intraocular pressure, corneal tomography were collected before wearing overnight orthokeratology, 1d, 1wk, 1month, 3mo, and every 6mo after wearing overnight orthokeratology,with axial length, corneal thickness, anterior chamber depth, corneal endothelial cell count, abjective refraction and tear film were also collected before and 2a after wearing overnight orthokeratology. In the control group, slit lamp, visual acuity, refraction and intraocular pressure were collected before wearing and 2a after wearing spectacles. Paired t test were used to compare the intragroup difference. One-way analysis of variance(ANOVA)was used to compare the differences among the groups. PRESULTS: The uncorrected visual acuity of the trial group was improved obviously after wearing Orthokeratology Lens 1d, the visual acuity of a group patients improved more significantly. The corneal curvature(including vertical curvature and horizontal curvature)of the trial group became more flat after wearing Orthokeratology Lens 2a and stopped 2 wk; The length of ocular axis was also increased, the growth rate of B group(0.33±0.31)mm was lower than that of group A(0.43±0.25)mm; Subjective refraction of myopia was increased 0.68±0.49D than wearing Orthokeratology Lens before, but compared with the growth(2.08±0.57)D of the control, the effect of myopia control was more obviously. Grade of dry eye was more severely than that of wearing Orthokeratology Lens before, but there was no significant difference between groups A and B. Compared with wearing Orthokeratology Lens before, corneal thickness, anterior chamber depth, corneal endothelial cell number and the intraocular pressure were all no significant differences between the trial and control group. CONCLUSION: Orthokeratology is a safe and effective method for the correction of myopia, and long-term use of Orthokeratology Lens can effectively control the development of myopia. Controlling of moderate myopia is more effective than that of low myopia.

• Lysozyme deposition starts saturating on the orthokeratology lens after one week. • Surface roughness increases after tear film component deposition for both lens materials. • Tear film component adsorption reduces transmission of visible light of both lens materials. To understand the effects of long-term deposition of tear film components on the surface and optical properties of orthokeratology (ortho -k) lenses, two different lenses, Brighten 22 and Optimum Extra, were tested here. Ortho-k lenses were immersed in artificial tears and cleaned with a commercial care solution repeatedly for up to 90 days. Both the daily and accumulated lysozyme deposition amounts using an Enzyme-Linked ImmunoSorbent Assay were then analyzed. The base curve, central thickness, power, and transmission of visible light, ultraviolet A, and ultraviolet B were analyzed before and after repeated tear film component deposition procedures. The surface roughness using atomic force microscopy was observed and an energy dispersive spectrometer was used to analyze the composition of the deposits. The highest levels of lysozyme were adsorbed on both lens materials during the first four days of the procedure and became saturated by day 6. For both lens materials, contamination on the lenses was easily observed by day 30, and the degree of surface roughness was higher. The transmission levels of different light spectrums were reduced showing that the optical characteristics of both lenses were also affected. The results provide in vitro evidence that lysozyme could not be completely removed from orthokeratology lenses. Both surface and optical properties were affected by the deposition of tear film components. However, only one commercial multipurpose care solution was used to clean the lens in this study when the main ingredient was a surfactant, and the results might be different when other care regimens with other key ingredients are used. In addition, whether tear film component deposition might result in increased risks of infection or corneal abrasion will require further investigation. [ABSTRACT FROM AUTHOR]

To investigate the effects of orthokeratology (ortho -k) lenses with aspheric and spherical base curve designs on corneal refractive power (CRP) and peripheral refraction. Children aged 8 to 12 years with myopia between −0.75 D to −4.00 D, astigmatism ≤1.00 D, and corneal astigmatism ≤1.50 D were randomly assigned to the base curve aspheric (BCA) and base curve spherical (BCS) ortho -k lens groups. CRP was assessed for the central 8 mm cornea along horizontal and vertical meridians, and peripheral refraction was measured at 10°, 20°, and 30° along the nasal and temporal retina. Primary measurements included relative corneal refractive power change (RCRPC) and relative peripheral refraction change (RPRC). The 3-month results of the 33 and 29 subjects (right eye only) in the BCA and BCS groups, respectively, were obtained. Nonsignificant differences were found in the baseline data between the two groups (p > 0.05). At the 3-month follow-up visit, the mean RCRPC in the BCA group (2.08 ± 0.65 D) was significantly greater than that in the BCS group (1.32 ± 0.81 D) (F 1,51 = 25.25, p < 0.001). The BCA group (-1.82 ± 0.65 D) exhibited a larger absolute RPRC than the BCS group (-0.98 ± 0.54 D) (F 1,57 = 33.73, p < 0.001). It was found that the BCA ortho -k lens resulted in a more aspheric treatment zone and a more myopic relative peripheral refraction (RPR) along the horizontal meridian. The more myopic RPR was contributed by a more hyperopic central refraction and a more myopic peripheral refraction in the BCA group. [ABSTRACT FROM AUTHOR]