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To evaluate the effectiveness and stability of refractive astigmatism reduction after penetrating femtosecond laser-assisted arcuate keratotomy performed at the time of femtosecond laser-assisted cataract surgery. Non-randomized retrospective data analysis of all patients that underwent femtosecond laser-assisted cataract surgery with femtosecond laser-assisted arcuate keratotomy over a 4-year period with a non-toric monofocal intraocular lens (2017–2021) at a tertiary care academic center. Postoperative visual acuity, manifest refraction, and predicted residual refractive error were also recorded at 1 month, 3–6 months, 12–18 months, and 2 years postoperatively. Preoperative keratometric astigmatism was compared to postoperative refractive astigmatism using vector calculations and the ASCRS double-angle plot tool. This study comprised 266 eyes (179 patients) that met inclusion criteria. The mean preoperative keratometric astigmatism magnitude was 0.99 ± 0.53 D. At 1 month, 3–6 months, 12–18 months, and 2 years postoperatively, the mean refractive cylinder was 0.49 ± 0.45 D, 0.49 ± 0.45 D, 0.55 ± 0.54 D, and 0.52 ± 0.46 D, respectively. Horizontal against-the-rule astigmatism showed a higher tendency toward undercorrection than vertical with-the-rule astigmatism, which had a slightly higher tendency toward overcorrection. With-the-rule astigmatism had smaller difference vectors between target-induced astigmatism and surgically induced astigmatism. Femtosecond laser-assisted arcuate keratotomy performed at the time of femtosecond laser-assisted cataract surgery was an effective option for correcting low-to-moderate corneal astigmatism for up to 2 years. [ABSTRACT FROM AUTHOR]

This study explores whether children's refractive errors and visual behaviors reverted to pre-COVID-19 levels a year after normal schooling resumed in Hong Kong as well as the impact of corneal and internal astigmatism on refractive astigmatism development. Vision survey data and questionnaire results collected in 2022 (n = 119) and 2020 (n = 173) were compared. Cross-sectional data showed similar proportions of astigmatism (cylindrical power ≥ 0.75 D) in the 2020 (49.1%) and 2022 cohorts (55.5%). Despite a 0.28 D increase in corneal astigmatism, a compensatory 0.24 D increase in internal astigmatism of opposite direction kept refractive astigmatism relatively stable. The questionnaire data showed that children spent an additional 0.5 h/day outdoors on weekends post-resumption of normal schooling but engaged in more near-work activities, especially non-screen near-work, by approximately 1 h/day on both weekdays and weekends. These findings were supported by longitudinal data from 72 children who participated in both surveys. This study highlights the significant role of corneal and internal astigmatism in refractive astigmatism changes. Despite the return to in-person classes, children's total near-work time increased and astigmatism remained high. These findings underscore the need for comprehensive strategies to reduce the high environmental risks for refractive error development in children. [ABSTRACT FROM AUTHOR]

Ahmed Elshahat, Abdelmonem M Hamed, Ashraf H El Habbak, Marwa Abdelshafy Tabl Department of Ophthalmology, Benha Faculty of Medicine, Benha University, Benha, Qalyopia, EgyptCorrespondence: Abdelmonem M Hamed, Email abdelmonem.abdelmonem@fmed.bu.edu.egPurpose: To evaluate the prevalence, magnitude, and direction of ocular residual astigmatism (ORA) in eyes with myopia and myopic astigmatism, and its interaction with refractive, anterior corneal, posterior corneal, and true net power astigmatism.Patients and Methods: Refractive surgery candidates with myopia and myopic astigmatism were studied. Refractive astigmatism (RA) was measured using the Nidek® AR-310A autorefractometer. Anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), and true net power astigmatism (TNP) were measured using the Wavelight® Oculyzer II. Astigmatism was converted from polar to vector notation. ORA was calculated by vector subtraction of ACA from RA vertexed to corneal plane. Compensation factor (CF) was calculated as the ratio of ORA that compensates ACA for both J0 and J45.Results: 154 eyes of 88 patients (mean age 31.7± 7.1 years) were included. With-the-rule (WTR) astigmatism was the most common for both RA (55.6%) and ACA (74%), while against-the-rule (ATR) was the most common for PCA (87.7%) and ORA (74.0%). The axes of RA and ACA were within 10° of each other in 46.8% of the eyes, and within 30° of each other in 76.0%. The mean difference in value between the axis of RA and ACA was 25.6°. 71.4% of eyes in the study had an ORA ≥ 0.5D, 44.1% had ORA ≥ 0.75D and 26% had ORA ≥ 1D. There was a statistically significant difference between ACA and each of RA and TNP. Using TNP to calculate ORA instead of ACA reduced its magnitude. RA is positively correlated to ACA and more strongly to TNP. The most common pattern of compensation between ORA and ACA was under-compensation for J0 (49%) and same-axis-augmentation for J45 (35%).Conclusion: ORA, PCA, and the interaction between ORA and ACA can affect results during refractive planning.Keywords: refractive astigmatism, anterior corneal astigmatism, posterior corneal astigmatism, refractive surgery

This study explores whether children’s refractive errors and visual behaviors reverted to pre-COVID-19 levels a year after normal schooling resumed in Hong Kong as well as the impact of corneal and internal astigmatism on refractive astigmatism development. Vision survey data and questionnaire results collected in 2022 (n = 119) and 2020 (n = 173) were compared. Cross-sectional data showed similar proportions of astigmatism (cylindrical power ≥ 0.75 D) in the 2020 (49.1%) and 2022 cohorts (55.5%). Despite a 0.28 D increase in corneal astigmatism, a compensatory 0.24 D increase in internal astigmatism of opposite direction kept refractive astigmatism relatively stable. The questionnaire data showed that children spent an additional 0.5 h/day outdoors on weekends post-resumption of normal schooling but engaged in more near-work activities, especially non-screen near-work, by approximately 1 h/day on both weekdays and weekends. These findings were supported by longitudinal data from 72 children who participated in both surveys. This study highlights the significant role of corneal and internal astigmatism in refractive astigmatism changes. Despite the return to in-person classes, children’s total near-work time increased and astigmatism remained high. These findings underscore the need for comprehensive strategies to reduce the high environmental risks for refractive error development in children.

Abstract Background To determine the preoperative factors influencing refractive astigmatism after cataract surgery for astigmatism correction by toric intraocular lens (IOL) implantation and to evaluate the prediction model using these factors. Methods Prospective, observational case series. The right eyes of forty consecutive patients with preoperative corneal astigmatism of the total cornea of 1.5 diopters (D) or more in magnitude and scheduled for implantation of a non-toric IOL during cataract surgery with a 2.4-mm temporal clear corneal incision were examined prospectively. The vertical/horizontal astigmatism component (J0) and oblique astigmatism component (J45) of refractive and corneal astigmatism were converted using power vector analysis. Multivariate regression analysis was performed with refractive astigmatism at three months postoperatively as the dependent variable, and preoperative parameters including age, sex, refractive astigmatism, corneal astigmatism, sphere, spherical equivalent, intraocular pressure, corneal thickness, anterior chamber depth, lens thickness, lens positions (tilt and decentration), axial length, and corneal higher order aberrations as independent variables. The root mean square (RMS) errors were calculated to express the regression model fit. Results The regression model for the J0 component was P o s t o p e r a t i v e r e f r a c t i v e J 0 = 1.05 × C o n e a l J 0 − 0.14 $$ Postoperative\kern0.34em refractive\kern0.2em J0=1.05\times Coneal\kern0.2em J0-0.14 $$ (R 2 = 0.96, P

Background: To determine the preoperative factors influencing refractive astigmatism after cataract surgery for astigmatism correction by toric intraocular lens (IOL) implantation and to evaluate the prediction model using these factors.Methods: Prospective, observational case series. The right eyes of forty consecutive patients with preoperative corneal astigmatism of the total cornea of 1.5 diopters (D) or more in magnitude and scheduled for implantation of a non-toric IOL during cataract surgery with a 2.4-mm temporal clear corneal incision were examined prospectively. The vertical/horizontal astigmatism component (J0) and oblique astigmatism component (J45) of refractive and corneal astigmatism were converted using power vector analysis. Multivariate regression analysis was performed with refractive astigmatism at three months postoperatively as the dependent variable, and preoperative parameters including age, sex, refractive astigmatism, corneal astigmatism, sphere, spherical equivalent, intraocular pressure, corneal thickness, anterior chamber depth, lens thickness, lens positions (tilt and decentration), axial length, and corneal higher order aberrations as independent variables. The root mean square (RMS) errors were calculated to express the regression model fit.Results: The regression model for the J0 component was [Formula: see text] (R2 = 0.96, P < 0.001). The model for the J45 component was [Formula: see text] (R2 = 0.72, P < 0.001). The mean RMS errors for preoperative corneal astigmatism alone and the multivariate model were 0.58 D and 0.46 D, respectively. There was a statistically significant difference between them (P = 0.02).Conclusions: Refractive astigmatism after implantation of a toric IOL can be predicted by the regression model more accurately than by corneal astigmatism alone. However, the prediction of oblique astigmatism remains a challenge. [ABSTRACT FROM AUTHOR]

Avi Wallerstein,1,2 Mathieu Gauvin,1,2 Mark Cohen2,3 1Department of Ophthalmology, Faculty of Medicine, McGill University, Montreal, QC, Canada; 2LASIK MD, Montreal, QC, Canada; 3Department of Surgery, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, CanadaClinical refractive astigmatism (RA) and topography-measured anterior corneal astigmatism (ACA) are rarely identical in magnitude and axis.1 This difference, when expressed vectorially, is termed ocular residual astigmatism (ORA).1 What accounts for this difference remains a topic that needs further research, and has implications as to what refraction to treat with topography-guided excimer laser ablations in order to maximize outcomes.1 This research letter investigates aspects of two contributing factors: posterior corneal astigmatism (PCA) and anterior corneal higher-order aberrations (CHOAs).

Background and objective: A pterygium is a triangular fibrovascular subepithelial ingrowth of degenerative bulbar conjunctival tissue over the limbus onto the cornea. Excision is indicated if the pterygium approaches the visual axis, causing loss of vision from irregular astigmatism or in cases of considerable irritation. This study aimed to determine the percentage of astigmatism in patients presented with pterygium and measure the effect of size (width and height) of pterygium on a degree of astigmatism and indication of early surgery. Methods: A hospital based cross-sectional study using non-probability convenience sampling was conducted in the ophthalmology department of Rizgary and Erbil teaching hospital in Erbil city from June 2015 to February 2016. Ninety-six eyes of eighty patients with pterygium were included in this study. Results: The mean age ± SD of the 80 patients included in the study was 37.5 ± 9.62 years ranging from 22-58 years. There were 45 male and 35 female patients. Two-thirds of eyes (72.6%) had with-the-rule astigmatism while 12.6 % of eyes had against-the-rule astigmatism. A highly significant strong correlation was seen between a fraction of corneal area encroached by pterygium with induced astigmatism (r = 0.727, P 4 mm area on the cornea) (r = 0.802, P 4 mm) as in this group they are encroaching on the visual axis.

Francisco Bandeira,1 Merce Morral,2 Daniel Elies,2,3 Sergio Eguiza,2 Spyridoula Souki,2 Felicidad Manero,2 Jose L Güell2–4 1Cornea and External Disease Department, Federal University of São Paulo, São Paulo, Brazil; 2Cornea and Refractive Surgery Unit, Instituto Microcirugia Ocular, Barcelona, Spain; 3European School for Advanced Studies in Ophthalmology (ESASO), Lugano, Switzerland; 4Ophthalmology, Universitat Autonoma de Barcelona (UAB), Barcelona, Spain Synopsis: Transitional toric intraocular lens (IOL) was developed to improve refractive outcomes in cataract surgery. We report refractive, vectorial outcomes, and stability of spherical equivalent over 12 months after implantation of this IOL.Purpose: To evaluate visual and refractive outcomes of a transitional conic toric intraocular lens (IOL) (Precizon®) for the correction of corneal astigmatism in patients undergoing cataract surgery.Setting: The Ocular Microsurgery Institute (IMO), a private practice in Barcelona, Spain.Design: This is a retrospective, non-randomized study.Methods: Retrospective chart review of 156 patients with preoperative regular corneal astigmatism >0.75 diopters (D) who underwent consecutive phacoemulsification and Precizon toric IOL implantation between January 2014 and December 2015 was performed. Two groups were divided according to attempted residual refraction: group 1 with emmetropia and group 2 with mild myopia for monovision. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and manifest refraction were analyzed preoperatively and 3, 6, and 12 months postoperatively.Results: Precizon toric IOL was implanted in 97 eyes of 61 patients. Six months postoperatively, none of the eyes lost any line of CDVA. In all, 98% of the eyes were within ±1.00 D of attempted spherical correction. The mean preoperative keratometric cylinder was 1.92 ± 1.04 D (range 0.75–6.78), and the mean postoperative refractive cylinder was 0.77 ± 0.50 D (range 0–2.25), with 81% of the eyes with ≤1.00 D of residual cylinder. Two IOLs required realignment due to intraoperative positioning error. Eleven eyes required enhancement with corneal refractive surgery.Conclusion: Preexisting regular corneal astigmatism was effectively and safely corrected by the implantation of the transitional conic toric IOL in patients undergoing cataract surgery. Keywords: corneal astigmatism, refractive astigmatism, keratometry, cataract surgery, toric intraocular lens, biometry, phacoemulsification

Mohamed A Heikal, Tarek Tawfik Soliman, Ayser Fayed, Abdelmonem M Hamed Department of Ophthalmology, Benha University, Benha, Egypt Purpose: To evaluate the efficacy of transepithelial corneal collagen crosslinking (TE-CXL) in patients with progressive keratoconus. Patients and methods: This is a prospective interventional consecutive study carried out on 30 eyes of 18 patients with progressive keratoconus who underwent TE-CLX using both ParaCel™ (riboflavin 0.25%, hydroxy propyl methyl cellulose, NaCl, ethylenediaminetetraacetic acid [EDTA], Tris, and benzalkonium chloride) and vibeX-Xtra (riboflavin 0.22%, phosphate-buffered saline solution). The procedure was carried out at Ebsar Eye Center in Egypt in the period from 2012 to 2014. The follow-up visits were scheduled on days 1, 3, 6, and 12 months after treatment. Results: There were statistically significant improvements (P

Purpose: To evaluate the correlation between refractive, corneal, and residual astigmatism and higher order aberrations (HOA) in refractive surgery candidates. Methods: Three hundred and seventy-five eyes of 188 patients aged 28.2 ± 6.24 years with a predominance of females (62.7%) were enrolled in this study. Refraction, topography (Orbscan IIz, Bausch & Lomb, Rochester, NY, USA), and aberrometry (Zywave, Bausch & Lomb, Rochester, NY, USA) were performed to determine refractive and corneal astigmatism and HOA for all participants. Ocular residual astigmatism was calculated using vector analysis. Results: The mean spherical equivalent was −3.59 ± 1.95 D and the mean refractive astigmatism was −1.97 ± 1.3 D. The mean HOA was 0.38 ± 0.15 μm in all cases, which increased with spherical equivalent (p

OBJETIVO: Determinar la efectividad de la fórmula de Haigis en el cálculo del poder dióptrico del lente intraocular. MÉTODOS: Se realizó un estudio descriptivo prospectivo, de pacientes operados de catarata mediante la técnica de Facoemulsificación en el Servicio de Microcirugía del Instituto Cubano de Oftalmología «Ramón Pando Ferrer» entre enero 2007 a enero 2008. Para el cálculo del poder del lente intraocular se empleó el IOL Máster y la fórmula de Haigis. La muestra de 101 pacientes, se seleccionó por el método aleatorio simple, de los cuales 28 fueron intervenidos en ambos ojos, para un total de 129 ojos. RESULTADOS: El equivalente esférico preoperatorio y posoperatorio no tuvieron diferencias, sí existieron entre esfera esperada y la obtenida. La mayor diferencia entre la esfera esperada y la obtenida fue encontrada en los pacientes hipermétropes. El astigmatismo refractivo fue bajo. La longitud axil posoperatoria no se modificó y la mejor agudeza visual sin corrección y con corrección mejoró en más de cuatro líneas en la cartilla de Snellen CONCLUSIÓN: Se demostró la efectividad de la fórmula de Haigis en el cálculo del poder del lente intraocular.OBJECTIVE: To determine the effectiveness of Haigis´formula in the intraocular lens power calculation. METHODS: A prospective and descriptive study was conducted in patients operated from cataract with phacoemulsification technique at the Microsurgery Service of "Ramón Pando Ferrer" Cuban Institute of Opththalmology from January 2007 to January 2008. The IOL Master and the Haigis´formula were used for the intraocular lens power calculation. The sample of 101 patients was selected by the simple random method, of whom 28 underwent surgery in both eyes, for a total number of 129 eyes. RESULTS: The Pre- and the post-operative spherical equivalents did not have any differences; but the expected sphere and the real sphere did show differences. The biggest difference between the expected sphere and the real one was found in the hypermetropic patients. The refractive astigmatism was low. The postoperative axil length did not change and the best visual acuity without/ with Correction improved by more than four lines in the Snellen´s chart. CONCLUSION: The effectiveness of Haigis´ formula was confirmed in the intraocular lens power calculation.

Purpose: To investigate the correlation of major components of ocular astigmatism in myopic patients in an academic hospital.Methods: This cross-sectional study was conducted on 376 eyes of 188 patients who were referred to Farabi Eye Hospital for refractive surgery. Preoperative examinations including refraction and corneal topography were performed for all candidates to measure refractive and corneal astigmatism. Ocular residual astigmatism was calculated using vector analysis. Pearson's correlation and ANOVA analysis were used to evaluate the strength of the association between different types of astigmatism. Both eyes were defined as cluster and the Generalized Estimating Equations (GEE) analysis were performed.Results: Mean age of 119 women (63.3%) and 69 men (36.7%) was 27.8 ± 5.7 years. Mean refractive error based on spherical equivalent was -3.59 ± 1.95D (range, -0.54 to -10.22D). Mean refractive and corneal astigmatism was 1.97 ± 1.3D and 1.85 ± 1.01D, respectively. Mean amount of ORA was 0.65 ± 0.36D.There was a significant correlation between ORA and refractive astigmatism(r=0.23, p<0.001), corneal and refractive astigmatism (r=0.91, p<0.001) and a weak correlation between ORA and corneal astigmatism (r=0.13, p=0.014). There was a significant correlation between J0 and J45 values of ORA and corneal astigmatism (p<0.001).Conclusion: There is a significant correlation between ORA and refractive astigmatism, refractive and corneal astigmatism and a weak correlation between ORA and corneal astigmatism in refractive surgery candidates. Identifying the type of astigmatism and preoperative measurement of ocular residual astigmatism is highly recommended prior to any refractive surgery, especially in cases with significant astigmatism. [ABSTRACT FROM AUTHOR]

Purpose To investigate the stability and effectiveness of T-flex toric intraocular lenses (IOLs) for the correction of regular corneal astigmatism during cataract surgery. Methods From October 2009 to January 2014 we enrolled patients receiving phacoemulsification and T-flex toric IOL implantation in the capsular bag at the Far Eastern Memorial Hospital. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), corneal astigmatism, refractive astigmatism, and the degree to which the IOL axis deviated from the demanded axis were recorded both prior to the operation and 6 months postoperatively. Results We enrolled 24 eyes of 24 consecutive patients in this study. The mean spherical power of the implanted toric IOLs was 17.13 ± 4.21 D (range 6.0–24.0 D) and the mean cylindrical power of the IOLs was 3.0 ± 0.86 D (range 2.0–5.0 D). At the 6-month follow up examination, the refractive astigmatism had improved from 3.21 ± 1.50 D to 0.77 ± 0.47 D ( p < 0.001) and the spherical equivalence had improved from 4.47 ± 5.43 D to 0.63 ± 0.49 D ( p = 0.007). The CDVA improved from 0.81 ± 0.45 logMAR to 0.09 ± 0.11 logMAR ( p < 0.001). The mean improvement from the preoperative CDVA to the postoperative UDVA was 5.3 lines on the Snellen chart. Ninety-two percent of our patients achieved a postoperative UDVA ≥20/40 and 67% achieved a postoperative UDVA ≥20/25. Conclusion The T-flex toric IOL can effectively reduce visually significant corneal astigmatism and improve uncorrected distance visual acuity during cataract surgery. [ABSTRACT FROM AUTHOR]

The purpose of this review is to evaluate the prediction of postoperative residual astigmatism and to determine the best prediction method for astigmatism correction. In recent findings for residual astigmatism in non-toric monofocal intraocular lens (IOL) implanted eyes, vector analysis can be used to correctly evaluate residual astigmatism by decomposing it. In predicting residual astigmatism, the with-the-rule (WTR) and against-the-rule (ATR) astigmatism components can now be almost predicted. This may be due to advances in inspection equipment and surgical technique. However, there are still issues with the oblique astigmatism component. In addition, corneal astigmatism is the most important predictor of postoperative residual astigmatism, and other predictors, such as refractive astigmatism, age, and lens thickness, have also been mentioned. However, all but corneal astigmatism are questionable because of the possibility of confounding variables. Total corneal astigmatism is more accurate in predicting residual astigmatism than anterior corneal astigmatism. Several predictions of residual astigmatism have been reported, but complete prediction has not been possible. Further research is needed, especially in predicting oblique astigmatism. However, I emphasize that the accuracy of predicting WTR and ATR astigmatism has improved considerably and can be predicted using regression equations with total corneal astigmatism.

Here we aimed to define keratometric and refractive astigmatism in a series of patients who underwent phacoemulsification, using small corneal incision and implantation of foldable intraocular lenses. Furthermore, we compared keratometric astigmatism and refractive astigmatism of the patients both before and after surgery. We performed a follow-up study of patients with newly diagnosed cataract before and after phacoemulsification surgery. Eighty eyes from 78 patients with a mean age of 62.9 ± 12.03 (32-86) years were studied. Thirty-nine (48.8 %) were male and 41(51.2 %) were female. All subjects underwent 3.5 mm corneal incision with the temporal (75 patients; 94 %) or superior (5 patients; 6 %) approach. The patients were followed for a mean of 74.21 ± 71.25 (30-400) days. Patients had higher values of keratometric measurements after surgery compared to those before surgery [45.81 ± 0.11 (45.06-45.94) vs. 45.2 ± 0.20 (44.6-45.41)] ( p < 0.001). There was no significant difference in the keratometric astigmatism, refractive astigmatism and keratometry axis pre- and postoperatively. The mean keratometric astigmatism was 0.9 ± 0.54 (0.00-4.00) diopters (D) preoperatively and 0.93 ± 0.45 (0.00-4.00) D postoperatively ( p = 0.444). The keratometric axis was 97.7 ± 9.4 preoperatively and 115 ± 15.8 postoperatively ( p = 0.185). Refractive astigmatism was 1.15 ± 0.77 (5-180) with the refractive axis of 89.7 ± 5.89 (5-180) degrees in the follow-up ( p = 0.752). Ninety percent of the patients had <1.00 D difference in the keratometric and refractive astigmatism, postoperatively. In conclusion while there is no significant difference in postoperative keratometric and refractive astigmatism in most of the eyes, about 10 % show >1 D difference in these measurements. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the correlation between refractive, corneal, and residual astigmatism and higher order aberrations (HOA) in refractive surgery candidates., Methods: Three hundred and seventy-five eyes of 188 patients aged 28.2 ± 6.24 years with a predominance of females (62.7%) were enrolled in this study. Refraction, topography (Orbscan IIz, Bausch & Lomb, Rochester, NY, USA), and aberrometry (Zywave, Bausch & Lomb, Rochester, NY, USA) were performed to determine refractive and corneal astigmatism and HOA for all participants. Ocular residual astigmatism was calculated using vector analysis., Results: The mean spherical equivalent was -3.59 ± 1.95 D and the mean refractive astigmatism was -1.97 ± 1.3 D. The mean HOA was 0.38 ± 0.15 μm in all cases, which increased with spherical equivalent (p < 0.05). There was a positive significant correlation between both corneal and refractive astigmatism and HOA (p < 0.05), but there was no significant correlation between residual astigmatism and HOA (p = 0.122)., Conclusion: The results of the study showed significant correlations between corneal and refractive astigmatisms and HOA.