Comparative analysis of surgically induced astigmatism following cataract surgery: influence of previous myopic correction and corneal parameters.

PURPOSE: This retrospective study investigated the impact of corneal parameters on surgically induced astigmatism (SIA) in eyes with prior myopic correction undergoing cataract surgery. SETTING: Department of Ophthalmology, San Marino Hospital, San Marino, Republic of San Marino. DESIGN: This case-control study analyzed existing data retrospectively, without randomization or masking. METHODS: Eighty eyes divided in group 1 (40 eyes previous underwent refractive surgery for myopia) and group 2 ( 40 myopic eyes) that underwent cataract surgery with intraocular lens (IOL) implantation were included. SIA was calculated using values from the IOL Master Zeiss 700 and mean pupil power (MPP) derived from the CSO Sirius Topographer (based on 3 mm pupil size) with vectorial analysis from doctor Hill software. RESULTS: No significant difference in SIA was observed between eyes with prior myopic photorefractive keratectomy and the control group (p > 0.05). SIA calculations using the IOL Master and CSO Sirius Tomographer yielded similar results. There was no significant correlation between SIA and axial length, corneal curvature, peripheral corneal thickness, or anterior chamber depth (p > 0.05). However, an inverse correlation was found between SIA and horizontal corneal diameter (p < 0.05). CONCLUSIONS: Corneal parameters, such as axial length, corneal curvature, peripheral corneal thickness, and anterior chamber depth, showed no significant influence on SIA. The inverse correlation between SIA and horizontal corneal diameter in study group suggests potential influence of white-to-white distance on SIA. These findings highlight the importance of considering corneal parameters for optimizing surgical outcomes.

Refractive outcomes after V4c Toric collamer lens implantation over 1y of follow-up.

AIM: To evaluate refractive outcomes and corneal astigmatism changes after Toric implantable collamer lens with a central port (V4c T-ICL) implantation over 1y of follow-up. METHODS: A retrospective study was performed including 50 eyes of 50 patients that underwent V4c T-ICL implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, refractive and corneal astigmatism changes and corneal coupling correction were evaluated preoperatively, 1 and 12mo postoperatively. Vector analysis was used for astigmatism changes. Coefficient of adjustment (CAdj) was calculated for corneal coupling analysis. RESULTS: The mean UDVA achieved was 0.03 logMAR at 1mo and remained unchanged throughout the whole follow-up (P=0.193). At the last visit, 84% of the eyes achieved a CDVA of 0.00 logMAR or better. Regarding spherical equivalent refraction (SEQ), 96% of eyes were ranges of ±1.00 D and 84% of them within ±0.50 D. Also, 94% of eyes had a remaining refractive cylinder within ±1.00 D and 78% of them within ±0.50 D. Both, SEQ and refractive cylinder, remain stable over the postoperative follow-up (P=1.000 and P=0.660, respectively). In terms of surgically induced astigmatism (SIA), no statistically significant differences were found over the follow-up (P=0.102) and under correction was found with a correction index lower than the unit at each visit. A keratometric astigmatism induced of 0.59±0.53 (vector mean: 0.26×73°) D was reached at the last visit. No significant changes in terms of corneal astigmatism orientation were reported over post-surgery visits (P=0.129 and P=0.097 at 1 and 12mo respectively). No clinical significance was found for CAdj on with-the-rule astigmatism. No postoperative complications resulting from the surgery were found. CONCLUSION: Refractive outcomes suggest that the V4c T-ICL implantation for correction of myopic astigmatism was satisfactory in terms of effectiveness, safety, and stability during 1y of follow-up. Corneal astigmatism induced by the incision around 0.5 D is achieved according to the remaining refractive cylinder found at one-year post-surgery. Corneal coupling analysis results in no unexpected spherical change.

A Comparative Study of the Effect of Femtosecond Laser-Assisted Cataract Surgery on Corneal Astigmatism in Post-LASIK Eyes and Virgin Eyes.

Purpose: To evaluate and compare the effect of femtosecond laser-assisted cataract surgery on corneal astigmatism in post-LASIK eyes and virgin eyes. Patients and Methods: Patients who underwent femtosecond laser-assisted cataract surgery were included in the study and categorized into two groups: Group A, consisting of patients with post-LASIK eyes, and Group B, consisting of patients with virgin eyes. Visual acuity, corneal astigmatism, and surgically induced astigmatism (SIA) were evaluated. Additionally, the correlation between SIA and preoperative corneal astigmatism, mean corneal curvature, and central corneal thickness was also analyzed. Results: A total of 168 eyes were enrolled in this study, with 62 eyes in Group A and 106 eyes in Group B. Significant differences in corneal astigmatism and SIA were observed between the two groups in the early postoperative period following cataract surgery (P<0.05). However, there was no significant difference at 6 months postoperatively (P>0.05). Corneal astigmatism demonstrated an against-The-rule shift in both groups postoperatively. No significant correlation was identified between SIA and preoperative corneal astigmatism, corneal curvature or corneal thickness. Additionally, there was no significant difference observed between the two groups in terms of uncorrected distance visual acuity (UDVA) at 6 months postoperatively. Conclusion: The effect of femtosecond laser-assisted cataract surgery on corneal astigmatism in post-LASIK eyes and virgin eyes was different in the early postoperative period. However, there was no significant difference at 6 months postoperatively. The post-LASIK eyes exhibited a delayed recovery compared to the virgin eyes.

Analysis of surgically induced astigmatism of the anterior, posterior, and total cornea after implantable collamer lens implantation: a comparative study between temporal and superior clear corneal incisions.

BACKGROUND: To comparatively analyze the surgically induced astigmatism (SIA) of the anterior, posterior, and total corneas of eyes undertaking implantable collamer lens (ICL) implantation with temporal or superior corneal incisions. METHODS: One hundred and nine eyes of 109 patients who received ICL implantation were recruited: 40 eyes had temporal incisions and 69 eyes had superior incisions. Total corneal refractive power (TCRP); simulated keratometry of the anterior (Sim-KAnt) and posterior (Sim-KPost) corneal curvature; and astigmatism of the anterior (CAAnt), posterior (CAPost), and total (CATCRP) cornea were recorded through a Pentacam preoperatively and 3 months postoperatively. The SIA of the anterior, posterior, and total cornea were also compared between the two groups. RESULTS: There were no significant intergroup differences for TCRP, Sim-KAnt, Sim-KPost, CAAnt, CAPost, or CATCRP, preoperatively. However, values of CAAnt, CAPost, and CATCRP with temporal incision were significantly higher than those parameters with superior incision postoperatively. All of the SIA of the anterior, posterior, and total cornea were significantly lower for temporal incision than those with a superior incision (p < 0.001, p = 0.006 and p = 0.001 respectively). Meanwhile, the superior incisions created against-the-rule (ATR) astigmatism, and temporal incisions always induce with-the-rule (WTR) astigmatism in total cornea. CONCLUSIONS: A superior incision may be suitable for correcting WTR astigmatism, while a temporal incision for correcting ATR astigmatism when using a non-toric ICL. Meanwhile, temporal incision could be a better choice with little preoperative astigmatism or that preoperative astigmatism would be corrected with toric ICLs. TRIAL REGISTRATION: Registration number: ChiCTR2100051739. Prospectively registered: 01 October 2021.

Refractive Astigmatism Outcomes of Femtosecond Laser-Assisted Arcuate Keratotomies Combined with Femtosecond Laser-Assisted Cataract Surgery: Two-Year Results.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Long Term Evaluation of Surgically Induced Astigmatism and Corneal Higher-Order Aberrations After 2.2 Mm Clear Corneal Incisions in Femtosecond Laser-Assisted Cataract Surgery: Temporal versus Superior Approach.

Purpose: To assess long term changes of the surgically induced astigmatism (SIA) and corneal higher-order aberrations (HOAs) after 2.2 mm clear corneal incisions (CCIs) in femtosecond laser-assisted cataract surgery and compare them between 2 types of CCIs: temporal and superior approach. Patients and Methods: Patients received the temporal CCIs (Group A) or the superior CCIs (Group B). Outcome measures included visual acuity, manifest refraction, corneal astigmatism, SIA, flattening effect, and corneal HOAs. Correlation between postoperative corneal HOA and SIA at each follow-up were analysed. Results: This study assessed data from 106 eyes, of which 64 in Group A and 42 in Group B. The two groups had similar postoperative visual acuity of distance, intermediate and near (all P > 0.05). SIA and corneal HOAs were significantly lower in Group A than Group B in the early postoperative period, while there was no significant difference in the late postoperative period. At 6 months after surgery, the arithmetic mean of SIA over corneal 4mm zone was 0.33 ± 0.19D for temporal incision, and 0.37 ± 0.25D for superior incision. For Group A, the correlations of HOAs and SIA persisted from 1 week to 6 months after surgery. For Group B, the changes in corneal HOAs were significantly related to the SIA at 1 week and 1 month postoperatively. Conclusion: This study suggested the consistency of increasing and recovering process of corneal HOAs and SIA after surgery. Compared to the superior incisions, temporal incisions might induce quicker corneal recovery and less change in SIA and corneal HOAs.

The comparison of corneal higher-order aberration and surgically induced astigmatism between the clear corneal incision and the limbus tunnel incision of posterior chamber implantable collamer lens implantation.

BACKGROUND: This study aimed to compare the corneal high-order aberrations and surgically induced astigmatism between the clear corneal incision and limbus tunnel incision for posterior chamber implantable collamer lens (ICL/TICL) implantation. METHODS: A total of 127 eyes from 73 myopic patients underwent ICL V4c implantation, with 70 eyes receiving clear corneal incisions and 57 eyes receiving limbus tunnel incisions. The anterior and back corneal surfaces were measured and the Root Mean Square of all activated aberrations (TRMS) was calculated, including higher-order aberration (HOA RMS), spherical aberration Z40, coma coefficients (Coma RMS) Z3-1 Z31, and surgically induced astigmatism (SIA). The measurements were taken preoperatively and postoperatively at 1 day, 1 week, and 1, 3, and 6 months. In this study, the corneal higher-order aberration was estimated as the Zernike coefficient calculated up to 5th order. The measurements were taken at a maximum diameter of 6.5 mm using Pentacam. RESULTS: One week after the operation, the corneal back Z31 of the clear corneal incision group was 0.06 ± 0.06, while the limbus tunnel incision group showed a measurement of 0.05 ± 0.06 (p = 0.031). The corneal back Z40 of the clear corneal incision group was -0.02 ± 0.25, compared to -0.04 ± 0.21 in the limbus tunnel incision group (p = 0.01). One month after the operation, the corneal back SIA of the clear corneal incision group was 0.11 ± 0.11, compared to 0.08 ± 0.11of the limbus tunnel incision group (p = 0.013), the corneal total SIA of the clear corneal incision group was 0.33 ± 0.30, compared to 0.15 ± 0.16 in the limbus tunnel incision group (p = 0.004); the clear corneal incision group exhibited higher levels of back astigmatism and total SIA than the limbus tunnel incision in the post-operation one month period. During the 6- month post-operative follow-up period, no significant difference in Z31, Z40, and other HOA RMS data was observed between the two groups. The total SIA of the corneal incision group and the limbus tunnel incision group were 0.24 ± 0.14 and 0.33 ± 0.32, respectively (p = 0.393), showing no significant difference between the two groups 6 months after the operation. CONCLUSION: Our data showed no significant difference in the high-order aberration and SIA between clear corneal incision and limbus tunnel incision up to 6 months after ICL-V4c implantation.

Evaluation of the efficacy and safety of phacoemulsification under the IOL protection: a randomized controlled clinical study / 中华实验眼科杂志

Objective:To observe the therapeutic effect of intraocular lens (IOL) protected phacoemulsification (PHACO) in patients with hard nucleus cataract.Methods:A randomized controlled clinical study was conducted.A total of consecutive 120 patients (120 eyes) with hard nucleus cataract of Emery grade Ⅳ or Ⅴ were enrolled from January 2019 to May 2022.The patients were randomly divided into PHACO group receiving routine PHACO, IOL protected PHACO group receiving PHACO under IOL protection, and extracapsular cataract extraction (ECCE) group receiving ECCE, with 40 cases (40 eyes) in each group.Finally, 99 patients completed the follow-up, including 30 cases (30 eyes) in PHACO group, 35 cases (35 eyes) in IOL protected PHACO group, and 34 cases (34 eyes) in ECCE group.The total operation time, intraoperative PHACO time and cumulative energy release of each patient were recorded.The corneal endothelial cell density (ECD), coefficient of variation in endothelial cell area (CV), hexagonal endothelial cell ratio (6A), corneal astigmatism and the number of eyes with different grades of uncorrected visual acuity were measured and compared after 3-month follow-up.The intraoperative and postoperative complications were recorded.This study adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Yanbian University Hospital (NO.2023002).Patients were informed of study content and purpose and signed a consent form before treatment.Results:There was no significant difference in ultrasonic energy and time between PHACO group and IOL protected PHACO group ( P=0.691, 0.982).The total operation time was (38.81±2.73) and (36.45±3.45) minutes in PHACO group and IOL protected PHACO group, significantly shorter than (69.60±4.35) minutes in ECCE group (both at P<0.001).There was no significant difference in age, sex, lens nucleus hardness and other baseline data among the three groups before operation (all at P>0.05).Three months after operation, the number of patients with higher uncorrected visual acuity in PHACO group and IOL protected PHACO group was larger than that in ECCE group ( P=0.006, 0.007).The ECD and 6A in IOL protected PHACO group were (2 155.57±177.88)/mm 2 and (41.31±5.18)%, respectively, which were significantly higher than (1 912.64±224.11)/mm 2 and (36.18±3.27)% in PHACO group, and the CV in IOL protected PHACO group was (50.34±5.90)%, which was lower than (55.67±3.30)% in PHACO group, showing statistically significant differences ( P=0.007, 0.003, 0.005).At 1 week and 3 months after the operation, the corneal astigmatism was significantly lower in IOL-protected PHACO group than in ECCE group, but higher than in PHACO group, and the difference were statistically significant (all at P<0.05). Conclusions:Compared with conventional PHACO, IOL-protected PHACO can effectively reduce the damage of corneal endothelium caused by ultrasonic energy, shorten the operation time and reduce postoperative inflammatory reaction compared with ECCE, and does not significantly increase postoperative corneal astigmatism.IOL-protected PHACO is an effective improved surgical method for patients with hard nucleus cataract.

Astigmatisme induit après phaco-alternative: à propos de 100 yeux opérés au CHU Donka, Conakry / Induced astigmatism after phaco-alternative: An Analysis of100 eyes operated at Donka University Hospital, Conakry

ntroduction.Après une opération par phaco-alternative chez les patients souffrantde cataracte,on peut observerune acuité visuelle non souhaitée. Une réfraction met en évidence souvent un astigmatisme important appelé astigmatisme induit. La qualité du résultat fonctionnel dépend en partie de ce dernier qu'il faut réduire à son minimum.Le but de notre étude était d'étudier l'astigmatisme induit après phacoalternative à Conakry et suggérer des recommandations pour l'amélioration de la qualité de la chirurgie.Méthodologie. Il s'agissait d'une étude transversale, descriptive et analytique d'une cohorte de patients opérés de la cataracte par phaco alternative de Juillet 2016 à Janvier 2017 (six mois)au CHU de Donka. Résultats.Nous avons inclusdans notre étude 100 yeux opérés par phaco-alternative avec un âge moyen de 62±12,18ans pour un sex ratio de 1. La tranche d'âge la plus représentée était cellede 61 -70 ans(38%). La femme ménagère était la plus touchée (39%).L'hypertension artérielleétait l'antécédent le plus retrouvée dans 23% des cas.L'œil gauche était le plus opéré (59%). L'acuité visuelle était réduite à la perception lumineuse dans 58% des cas en préopératoire, 95% des astigmatismes préopératoiresétaient inférieurs à 2D et 57% selon la règle. La puissance moyenne de l'implant après biométrie était de 19±2,38 dioptries et 50% des patientsont reçu l'implant calculé.L'œdème cornéen était la complication précoce la plus fréquenteConclusion.la phacoalternativeavec incision supérieure linéaire induit un astigmatisme contre la règle de 3,15 dioptries en moyenne

Introduction.After a phaco-alternative operation in patients suffering from cataracts, unwanted visual acuity may be observed. Refraction often reveals significant astigmatism called induced astigmatism. The quality of the functional result partly depends on the amount of induced astigmatism, which needs to be minimized. The aim of our study was to investigate induced astigmatism after phaco-alternative in Conakry and suggest recommendations for improving the quality of surgery. Methodology.This was a cross-sectional, descriptive, and analytical study of a cohort of cataract patients operated by phaco-alternative from July 2016 to January 2017 (six months) at Donka University Hospital. Results.We included 100 eyes operated by phaco-alternative with an average age of 62±12.18 years and a sex ratio of 1. The most represented age group was 61-70 years (38%). Homemakers were the most affected group (39%). Hypertension was the most commonly found history in 23% of cases. The left eye was the most operated on (59%). Visual acuity was reduced to light perception in 58% of cases preoperatively, 95% of preoperative astigmatism was less than 2D, and 57% were with-the-rule. The average power of the implant after biometry was 19±2.38 diopters, and 50% of patients received a calculated implant. Corneal edema was the most common early complication. Conclusion.Phaco-alternative with a linear superior incision nduces an astigmatism against-the-rule of 3.15 diopters on average.

The impact of posterior corneal astigmatism on the surgical planning of toric multifocal intraocular lens implantation.

Purpose: To investigate the influence of posterior corneal astigmatism on the prediction accuracy of toric multifocal intraocular lens (IOL) calculation. Methods: The keratometric astigmatism measured by Lenstar LS 900 (KCAL), keratometric astigmatism (KCAP) and total corneal astigmatism (TCA) measured by Scheimpflug camera (Pentacam HR) were documented and analyzed accordingly. Three deduction models using different parameters were compared. Model 1: KCAL â€‹+ â€‹keratometric corneal surgically induced astigmatism (KCSIA, 0.30 D @ 50°); Model 2: KCAP â€‹+ â€‹KCSIA); Model 3: TCA â€‹+ â€‹total CSIA (TCSIA, 0.23 D @ 50°). The prediction errors of each model as the difference vector between the actual and the intended residual astigmatism were compared. Results: Seventy-six eyes implanted with toric multifocal IOLs were included in this study. The vector differences of the actual KCSIA and TCSIA were statistically significant in the total sample and against-the-rule (ATR) subgroup (both P â€‹< â€‹0.05). Model 1 deduced the smallest mean values of prediction error, while that of Model 3 were smaller than that of Model 2, both in the total sample and the ATR subgroups (all P â€‹< â€‹0.05). Meanwhile, in the total sample and ATR subgroups, the centroid vector magnitudes of Model 3 were smaller than that of Model 1 (0.31 â€‹± â€‹0.76 D and 0.39 â€‹± â€‹0.76 D). Conclusions: The calculation of toric multifocal IOL should be individualized especially in the ATR eyes for the impact of PCA on the estimation of the preoperative corneal astigmatism and the CSIA.

Short-Term Impact of Different Corneal Incision Positions on Postoperative Astigmatism and Visual Quality After SMILE Surgery.

INTRODUCTION: This study aimed to evaluate the short-term impact of different incision positions on astigmatism and visual quality after small incision lenticule extraction (SMILE) surgery. METHODS: This prospective study enrolled patients who decided to have SMILE to correct myopia. Patients were randomly allocated into three groups of different incision positions (group A, B, and C with incision position at 90°, 120°, and 150° respectively). Preoperative and postoperative visual acuity, spherical equivalent, and high-order aberrations (HOAs) were measured and compared among groups. Astigmatism was analyzed with the ASSORT Group Analysis Calculator based on the Alpins method. RESULTS: A total of 148 eyes were included for analysis (48 eyes in group A, 50 eyes in group B, and 50 eyes in group C). At 1 month postoperatively, the mean uncorrected distance visual acuity (UDVA) logMAR in group A, B, and C was - 0.03, - 0.03, and - 0.04, respectively. The mean corrected distance visual acuity (CDVA) logMAR in group A, B, and C was - 0.03, - 0.04, and - 0.04, respectively (P > 0.05). The mean postoperative spherical equivalent (SE) values were - 0.01 ± 0.38, - 0.07 ± 0.39, and - 0.16 ± 0.49 (D) in group A, B, and C, respectively (P > 0.05). There was no statistically significant difference in preoperative and postoperative magnitude of astigmatism among different groups (P > 0.05). Significant differences were found in the distribution of astigmatism axis among the three groups at 1 day (P = 0.02) and 1 week (P = 0.02) postoperatively. However, such differences were no longer significant at 1 month after surgery (P > 0.05). No significant differences were found in HOAs among different groups 1 month after surgery (P > 0.05). CONCLUSION: Different incision positions have no effect on postoperative astigmatism and visual quality 1 month after SMILE surgery, though differences were found in the distribution of the astigmatism axis within 1 week after the surgery.

CHANGE OF SURGICALLY INDUCED CORNEAL ASTIGMATISM AND POSITION OF ARTIFICIAL INTRAOCULAR LENS OVER TIME.

AIMS: To analyze changes in surgically induced corneal astigmatism and articial intraocular lens (IOL) stability over time following cataract surgery. To compare the interchangeability of measurements between an automatic keratorefractometer (AKRM) and a biometer. MATERIAL AND METHODS: In this prospective observational study, the above-mentioned parameters were collected from 25 eyes (25 subjects) on the first day, first week, first and third month after uncomplicated cataract surgery. We used IOL-induced astigmatism (difference between refractometry and keratometry) as an indirect indicator of IOL stability change. We used the Blant-Altman method to analyze consistency between devices. RESULTS: At the above time points, surgically induced astigmatism (SIA) decreased as follows: 0.65 D; 0.62 D; 0.60 D and 0.41 D (in the first day, week, month and third month respectively). Astigmatism induced by changes of the position of the IOL varied as follows: 0.88 D; 0.59 D; 0.44 D and 0.49 D. Changes in both parameters were statistically significant (p0.05). CONCLUSION: Both surgically induced astigmatism and astigmatism induced by IOL decreased over time, in which both changes were statistically significant. The decrease in SIA was most pronounced between the first and third month after surgery. For IOL-induced astigmatism, the greatest decrease was within the first month after surgery. The differences in measurement between the biometer and AKRM were statistically insignificant, but the clinical interchangeability between the given methods is questionable, especially with regard to measurement of the astigmatism angle.

Estimation of surgically induced astigmatism after small-incision cataract surgery done by junior residents.

Purpose: To estimate the postoperative astigmatism after small-incision cataract surgery (SICS) done by junior residents at the end of 1 and 3 months. Methods: This observational longitudinal study was conducted at the Department of Ophthalmology of a tertiary eye care hospital and research center. 50 patients enrolled in the study underwent manual small incision cataract surgery by junior residents. Preoperative detailed ocular examination was done, which included keratometric estimation using autokeratometer (GR-3300K). Incision length, distance of incision from the limbus, and type of suturing technique were noted. Postoperatively, keratometric readings were noted at 1 and 3 months. Astigmatism (surgically induced astigmatism [SIA]) was estimated using Hill's SIA calculator version 2.0. All the analyses were performed using Statistical Package for the Social Sciences (SPSS) ver. 26.0 (IBM Corp., USA) software, and the statistical significance was tested at a 5% level. Results: Out of 50 patients, 54% had SIA between 1.5 and 2.5 D and 32% had SIA of more than 2.5 D. Only 14% had SIA less than 1.5 D at the end of 1 month. While 52% had SIA between 1.5 and 2.5 D, 22% had SIA between 1.5 and 2.5 D and 26% had SIA less than 1.5 D at the end of 3 months. Conclusion: The SIA in most of the SICS done by junior residents was above 1.5 D. It depended mainly on the incision length, its distance from the limbus, and the suturing technique.

Functional Profile of a Customized Wound Parameter in Femtosecond Laser-Assisted Corneal Incision for Cataract Surgery.

Purpose: To evaluate the performance of optimized parameters of femtosecond laser for cataract surgery corneal incisions regarding opening, patency and surgically induced astigmatism (SIA). Patients and Methods: Patients scheduled for femtosecond laser-assisted cataract surgery between May 2018 and December 2018 were enrolled. Inclusion criteria were a healthy preoperative cornea and uneventful FLACS. Exclusion criteria were preoperative corneal astigmatism over 1.0 D, previous corneal trauma or pathologies. Clinical data were obtained from the electronic medical records. Surgical planning was based on Scheimpflug tomography images for keratometric data. At postoperative day 60, new keratometric evaluation was performed, obtained using the same device. Results: 101 eyes (61 patients) matched the criteria for SIA analysis. Overall mean SIA was 0.44 ± 0.33 D (0-1.55 D). Axis and size did not have any statistically significant effects on SIA. The overall centroid of the SIA was 0.11. For the opening analysis, was included 156 eyes (79 patients). Successful opening in 87.7% of cases (137 eyes). Temporal incisions had the highest success rate (98.36%). Conclusion: These femtosecond laser parameters showed high opening rates with low opening times. These optimized parameters led to a low incidence of SIA and high predictability regardless of incision site and size. The association between incision opening and SIA was not statistically significant. There was, however, an association between incision opening success and site.

The influencing factors of surgically induced astigmatism in phacoemulsification / 西安交通大学学报(医学版)

【Objective】 To investigate the influencing factors of surgically induced astigmatism (SIA) in phacoemulsification. 【Methods】 Cataract phacoemulsification was performed in 69 patients with regular corneal astigmatism from December 2021 to March 2022. SIA of the anterior corneal surface, posterior corneal surface and simulated keratometry (SimK) in the diameter range of 3 mm, 5 mm and 7 mm centered at the apex of the cornea was observed. Pearson correlation analysis was used to analyze SIA with age, axial length (AL), anterior chamber depth (ACD), white-to-white (WTW), and central corneal thickness (CCT). Multiple linear regression was used to analyze the influencing factors of SIA. 【Results】 The mean age of the 69 patients was (63.25±14.74) years old, and 28 (40.58%) were male. The analysis found that the |SIA| of SimK was negatively correlated with WTW (r=-0.265, P=0.028), the |SIA| of 3 mm, 5 mm, 7 mm anterior surface was negatively correlated with WTW (r=-0.320, P=0.007; r=-0.337, P=0.005; r=-0.287, P=0.017), and the |SIA| of 3 mm, 5 mm, 7 mm posterior surface was negatively correlated with AL (r=-0.390, P=0.001; r=-0.352, P=0.003; r=-0.317, P=0.008). Multiple regression analysis showed that WTW was negatively correlated with |SIA| of SimK, 3 mm, 5 mm, 7 mm anterior surface and 3 mm posterior surface (B=-0.261, P=0.047; B=-0.387, P=0.016; B=-0.323, P=0.009; B=-0.297, P=0.041; B=-0.085, P=0.049). WTW was positively correlated with XSIA of 3 mm anterior surface, YSIA of 5 mm, and 7 mm anterior surface (B=0.347, P=0.040; B=0.318, P=0.034; B=0.403, P=0.010). AL was negatively correlated with |SIA| on the posterior surface of 3 mm and 5 mm (B=-0.023, P=0.021; B=-0.034, P=0.030). 【Conclusion】 During cataract surgery, the effect of ocular biological parameters such as axial length and corneal diameter on SIA should be considered.

Comparison of surgically induced astigmatic changes after cataract surgery in post-Laser in situ keratomileusis corneas versus virgin eyes / Comparação de alterações astigmáticas induzidas cirurgicamente após cirurgia de catarata em córneas ceratomileusis in situ pós-Laser versus olhos virgens

ABSTRACT Purpose: Postoperative refraction in modern mi­croincision cataract surgery gained extra importance in patients with the previous laser-assisted in situ keratomileusis (LASIK) surgery. The surgically induced astigmatic changes in those eyes may differ not only in magnitude but also in direction compared to virgin corneas. This study aimed to compare the surgically induced astigmatic changes after microscopic cataract surgery between post-LASIK corneas and virgin eyes. Methods: Cases that underwent microincision cataract surgery in eyes with and without previous LASIK surgery were reviewed. The demographics, the axial length at cataract surgery, the central corneal thickness, spheric and cylindric values, keratometry readings, and postoperative posterior corneal astigmatism were retrospectively evaluated. A modified Alpins method was used for astigmatic vector analysis, and baseline astigmatism, surgically induced astigmatism, difference vector, flattening effect, and torque were assessed. Results: A total of 42 eyes from 24 subjects was evaluated. Group I consisted of 14 eyes with the previous LASIK, and Group II included 28 eyes without any refractive surgery. Preoperative mean central corneal thickness in Group I was significantly thinner (p=0.012). There was no significant difference in baseline astigmatism between the groups regarding magnitude and power vectors. After microincision cataract surgery, there were no significant differences in mean spheric and cylindric values and mean keratometry readings (all p>0.05). However, surgically induced astigmatism and difference vector were significantly higher on J45 vector component in post-LASIK eyes and microincision cataract surgery steepening effect on post-LASIK corneas was significantly higher than those in virgin eyes (p=0.001, p=0.002 and p=0.018, respectively). Conclusions: Cataract surgery has steepened the corneas in both groups with a significantly higher steepening effect in post-LASIK eyes. Certainly, corneal topography cataract surgery is particularly helpful to provide more precise surgically induced astigmatism interpretations.

RESUMO Objetivo: A refração pós-operatória na cirurgia mo­derna de catarata por microincisão ganha ainda mais importância em pacientes com cirurgia prévia de ceratomileuse in situ assistida por laser (LASIK). As alterações astigmáticas induzidas cirurgicamente nesses olhos podem diferir não apenas em magnitude, mas também em direção em comparação com córneas virgens. O objetivo deste estudo foi comparar as alterações astigmáticas induzidas cirurgicamente após cirurgia de catarata por microincisão entre córneas pós-LASIK e olhos virgens. Métodos: Foi revisada uma série de casos de cirurgia de catarata por microincisão em olhos com e sem cirurgia LASIK anterior. Os dados demográficos, o comprimento axial no momento da cirurgia de catarata, a espessura central da córnea, os valores esféricos e cilíndricos, as leituras da ceratometria e o astigmatismo corneano posterior pós-operatório foram avaliados retrospectivamente. O método Alpins modificado foi usado para análise vetorial astigmática e foram avaliados o astigmatismo basal, o astigmatismo induzido cirurgicamente, o vetor de diferença, o efeito de achatamento e o torque. Resultados: Ao todo, 42 olhos de 24 indivíduos foram avaliados. O Grupo I consistiu em 14 olhos com LASIK prévio; o Grupo II incluiu 28 olhos sem qualquer cirurgia refrativa. A média da espessura corneana central pré-operatória no Grupo I foi significativamente mais fina (p=0,012). Não houve diferença significativa no astigmatismo basal entre os grupos em termos de magnitude e vetores de potência. Após a cirurgia de catarata por microincisão, não houve diferenças significativas nos valores médios esféricos, cilíndricos e leituras médias de ceratometria (todos com p>0,05). No entanto, o astigmatismo induzido cirurgicamente e o vetor de diferença foram significativamente maiores no componente do vetor J45 em olhos pós-LASIK, e o efeito de aumento da inclinação pela cirurgia de catarata por microincisão nas córneas pós-LASIK foi significativo em comparação com olhos virgens (p=0,001, p=0,002 e p=0,018, respectivamente). Conclusões: A cirurgia de catarata aumentou a inclinação das córneas em ambos os grupos, sendo esse aumento significativamente maior nos olhos pós-LASIK. Certamente, a topografia da córnea antes da cirurgia de catarata é particularmente útil para fornecer interpretações mais precisas do astigmatismo induzido cirurgicamente.

The Impact of Posterior Corneal Astigmatism on Surgically Induced Astigmatism in Cataract Surgery.

Purpose: This study aimed to evaluate the changes in posterior corneal astigmatism after cataract surgery and provide a theoretical basis to accurately evaluate the total corneal astigmatism (TA) to be corrected before toric intraocular lens (IOL) implantation. Patients and Methods: Sixty-two patients (89 eyes) who underwent phacoemulsification combined with toric IOL implantation (AcrySof IQ Toric SN6AT2-T9) at Shanxi Eye Hospital between January 2017 and September 2018 were enrolled. Surgically induced astigmatism of the posterior cornea (SIAPA) was analysed using vector analysis during pentacam examination. Results: The vector variances of keratometric astigmatism (KA), TA, and posterior corneal astigmatism (PA) preoperatively and postoperatively in the "with-the-rule (WTR) astigmatism" group and "overall patient" group were statistically significant (P < 0.05). A statistically significant difference was observed between surgically induced KA (SIAKA) and surgically induced astigmatism of the total cornea (SIATA) for all patients, including those with WTR astigmatism. For all patients, SIAKA was less than SIATA by 0.05 ± 0.21 D, and for patients with WTR astigmatism, SIAKA was less than SIATA by 0.09 ± 0.22 D. For patients in the "against-the-rule (ATR) astigmatism" group, there were no statistically significant differences between SIAKA and SIATA, although SIAKA was greater than SIATA by 0.03 ± 0.18 D. When PA ≤0.4 D or KA ≤2.0 D, SIAPA can be ignored. However, when PA >0.4 D or KA >2.0 D, ignoring SIAPA caused by cataract surgery incision will cause SIAKA in patients with WTR astigmatism to underestimate SIATA, while SIAKA in patients with ATR astigmatism will cause an overestimation of SIATA. Conclusion: SIA on the posterior corneal astigmatism may have a significant role on more precise planning of toric IOL implantation, especially in cases with higher preoperative anterior or posterior corneal astigmatism.

Changes in Vector Astigmatism After Superotemporal Versus Temporal Clear Corneal Incision Cataract Surgery.

PURPOSE: To investigate vector and refractive astigmatism changes after superotemporal versus temporal clear corneal incision cataract surgery. METHODS: Patients were diagnosed with age-related cataract with corneal astigmatism < 1.5 diopters (D) and were divided into two groups: superotemporal incision (R group) and temporal incision (L group). Uncorrected visual acuity, manifest refraction, corneal topography, anterior segment optical coherence tomography was performed pre- and six months postoperatively. Total ocular astigmatism, corneal astigmatism, vector of surgically induced corneal astigmatism (SICA), non-corneal ocular residual astigmatism (N-CORA), postoperative intraocular lens decentration and tilt were analyzed.  Results: Thirty-eight subjects were included: 21, R group; 17, L group. After surgery, the N-CORA decreased significantly from 1.17±0.72 D to 0.73±0.47 D in all patients (P=0.001), 1.03±0.52 D to 0.70±0.40 D in the R group (P=0.005) and 1.35±0.90 D to 0.78±0.55 D in the L group (P=0.033). Significant differences between t:he R and L groups were found in the postoperative meridian of anterior corneal astigmatism (75.95±52.50 vs 116.79±47.29; P=0.017), total corneal astigmatism (51.65±42.75 vs 95.20±57.32; P=0.011), J45 change vector of SICA in the anterior cornea (-0.10±0.18 vs 0.00±0.11; P=0.048) and total cornea surface (-0.14±0.17 vs 0.03±0.12; P=0.001).  Conclusion: The N-CORA decreased significantly after cataract surgery. Superotemporal and temporal incisions caused differences in the meridian components of oblique astigmatism in some patients but did not have a significant effect on the magnitude of corneal astigmatism.

Roles of Toric intraocular Lens implantation on visual acuity and astigmatism in glaucomatous eyes treated with iStent and cataract surgery.

BACKGROUND: To assess the efficacy of toric intraocular lenses (IOLs) in combined cataract and minimally invasive glaucoma surgery (MIGS), visual and refractive outcomes were compared between eyes implanted with non-toric and toric IOLs during iStent triple procedures. METHODS: In this retrospective study, open angle glaucoma eyes with preexisting corneal astigmatism of -1.5 diopter (D) or more and implanted with non-toric (n = 9) or toric (n = 9) IOLs were included. The main outcome measures were the intergroup difference in the uncorrected visual acuity (UCVA) and refractive astigmatism at 3 months postoperatively. RESULTS: Preoperatively, the logarithm of the minimum angle of resolution (logMAR) UCVAs and refractive astigmatism were equivalent between the groups. Postoperatively, the logMAR UCVA (non-toric, 0.45 ± 0.31; toric, 0.14 ± 0.15; P = 0.021) was significantly better and the refractive astigmatism (non-toric, -2.03 ± 0.63 D; toric, -0.67 ± 0.53 D; P = 0.0014) significantly less in the toric group. The toric group had postoperative improvements in the logMAR UCVA (-0.21, P = 0.020) and refractive astigmatism (+ 1.72 D, P = 0.0039). Vector analyses showed the postoperative centroid magnitude and confidence eclipses of refractive astigmatism was less in the toric group (0.47 D at 173°±0.73D) than the non-toric group (1.10 D at 2°±1.91D). Postoperatively, 78% of eyes in the toric group had 1.0 D or less refractive astigmatism compared with 11% in the non-toric group. Surgically induced astigmatism (non-toric, 0.18 D at 65°; toric, 0.29 D at 137°) did not differ between groups. CONCLUSION: Use of toric IOLs is a reasonable option for better visual outcomes when the combined cataract and iStent surgery is performed in glaucomatous eyes with corneal astigmatism.

Refractive Changes after Glaucoma Surgery-A Comparison between Trabeculectomy and XEN Microstent Implantation.

Best-corrected visual acuity often decreases temporarily or permanently after trabeculectomy (TE). The purpose of this study was to compare visual acuity and refractive changes after TE or XEN microstent implantation (XEN) in primary open-angle glaucoma (POAG) or pseudoexfoliation glaucoma (PEX) cases naïve to prior glaucoma surgery over a 24-month follow-up period. We analyzed 149 consecutive glaucoma patients who received either TE or XEN because of medically uncontrollable POAG or PEX. Intraocular pressure (IOP), IOP-lowering medication use, subjective and objective refraction and best-corrected visual acuity were evaluated. In addition, surgically induced astigmatism (SIA) was calculated and compared using the vector analysis method described by Jaffe and Clayman. A total of 93 eyes (85 POAG; 8 PEX) were treated with TE and 56 eyes (50 POAG; 6 PEX) with XEN. After 24 months, the mean IOP and number of IOP-lowering medications used decreased significantly after TE (p < 0.01) and XEN (p < 0.01). In the TE group, mean best-corrected visual acuity (BCVA) changed from 0.16 ± 0.26 to 0.23 ± 0.28 logMAR (p < 0.01) after 24 months, while mean BCVA did not change significantly in the XEN group (preoperative: 0.40 ± 0.50 logMAR, postoperative: 0.36 ± 0.49 logMAR; p = 0.28). SIA was almost the same in both groups at the end of the 24-month follow-up period (0.75 ± 0.60 diopters after TE and 0.81 ± 0.56 diopters after XEN; p = 0.57). In addition, there was no significant correlation between SIA and the observed BCVA changes or SIA and IOP reduction 12 or 24 months after TE or XEN. Our results demonstrate that TE and XEN are effective methods for reducing IOP and IOP-lowering medication use. The SIA was nearly similar in both groups. The SIA does not seem responsible for the decreased visual acuity after TE.