High Astigmatism Research Articles

Management of post-keratoplasty ametropia.

Even after a successful corneal transplant, patients experience severe refractive errors, impeding their rehabilitation and satisfaction. Refractive errors can be caused by recipient pathology and corneal thickness, as well as intraoperative factors such as donor-host discrepancy, recipient's eccentric trephination, vitreous length, wound apposition, technique of suturing, and suture material. Also, wound healing and the interim between keratoplasty and suture removal contribute to astigmatism. Lamellar keratoplasty outperforms penetrating keratoplasty in terms of endothelial cell loss and endothelial graft rejection, yet the risk of developing refractive errors is comparable. Nonsurgical interventions such as spectacles and lenses fail to provide desirable vision in cases with high astigmatism and corneal irregularity. When these limitations are encountered, surgical interventions including incisional keratotomy, wedge resection, laser refractive surgeries, intracorneal segments, and intraocular lens implantation are employed. However, occasionally, none of these approaches deliver the desired effects, leading to the need for a repeat keratoplasty.

Role of Epithelial Mapping in Differentiation Between Early Keratoconus And High Regular Astigmatism Using Anterior Segment Optical Coherence Tomography

Role of Epithelial Mapping in Differentiation Between Early Keratoconus And High Regular Astigmatism Using Anterior Segment Optical Coherence Tomography

Toric implantable phakic contact lens versus bioptics for the correction of moderate to high myopia and astigmatism

Purpose To compare refractive and visual outcomes and patient satisfaction of toric implantable phakic contact lens (T-IPCL) versus bioptics (IPCL followed by femtosecond laser assisted in-situ keratomileusis) in myopia (moderate to high) with astigmatism. Patients and methods A total of 13 eyes underwent T-IPCL implantation, and 11 eyes were corrected using bioptics. Complications, uncorrected and corrected distance visual acuities, refraction, safety, efficacy, predictability, tear-film break-up time, contrast sensitivity, and patient satisfaction were assessed 6 months postoperatively. Results No complications were reported. Mean spherical equivalent was −0.62±0.49 D in T-IPCL and −0.55±0.26 D in the bioptics group (P=0.464). In 10 (76.9%) eyes of T-IPCL and 11 (100%) eyes of bioptics, the spherical equivalent and astigmatism were within ±1 D, respectively. A significantly better astigmatic correction was demonstrated in the bioptics group as confirmed by vector analysis (P<0.001). Loss of lines was not reported; both uncorrected and corrected distance visual acuities improved significantly (P<0.05), with no significant differences (P>0.05). Safety indices were 1.15±0.08 and 1.1±0.09 and efficacy indices were 1.04±0.11 and 1.03±0.06 in T-IPCL and bioptics groups, respectively, which were insignificant. The contrast sensitivity and tear-film break-up time were significantly better in the T-IPCL group (P<0.001). Distant vision satisfaction was better in the bioptics group, whereas glare, halos, and dry eye satisfaction were better in the T-IPCL group (P<0.05). Conclusion Both T-IPCL and bioptics can successfully correct moderate to high myopia with astigmatism. The T-IPCL carries better optical quality with less glare, halos, and dry eye. Bioptics gives better astigmatic correction and distant vision satisfaction but carries the risk of a second surgical intervention.

Analysis on ocular biometric parameters in adult cataract surgery

Introduction: Biometrics are crucial in calculating IOL power for best refractive advantage in cataract surgery. Regional data provides insights on corneal astigmatism and facilitates forecasts but data for Sri Lankan population is lacking.Objective: To identify ocular biometry characteristics in Sri Lankans and compare with other populations.Method: A cross-sectional retrospective study assessed ocular biometry characteristics in consecutive cataract surgery candidates at a tertiary unit in National Eye Hospital of Sri Lanka between February and August 2021. Data from 237 eyes in 237 candidates of age over 40 and under 80 years were analysed. Data on Keratometry(K), axial length(AL) and IOL power were statistically analysed through SPSS software. Sample was divided as: age between 40-60 years and 60-80years. Descriptive statistics and unpaired t-test to compare means between groups were utilised.Results: Mean Age was 62.71±7.89 years. Mean AL was 23.11±1.11mm (range 21.00-30.56)mm with majority between 22-24mm(72.6%). Mean K was 44.25±1.57mm. IOL powers most used were between 23-25D (46.3%) (range 4D,28D). Mean astigmatism was 0.82±0.78D and 26.6%, 5.9% and 1.3% had over 1.0D, 2.0D and 3.0D respectively.Discussion: In males mean K was lower (43.80±1.62 vs 44.61±1.44) (p=0.00) and AL was longer (23.31±1.20 vs 22.94±1.01) (p=0.013). The older age group had shorter AL (p=0.006) and higher astigmatism(p=0.049). AL in our sample was shorter than Caucasians but comparable with other South Asian studies. Astigmatism prevalence was lower than other studies.Conclusion: This study gives an insight of ocular biometrics, corneal astigmatism and common IOL powers in this sample. A larger sample size study may project figures for entire Sri Lankan population.

Analysis of visual and refractive results after wedge resection for high astigmatism after penetrating keratoplasty in keratoconus.

To analyze visual and refractive results after wedge resection to correct high astigmatism after penetrating keratoplasty (PK) for keratoconus. Cornea Unit of the Centro de Oftalmología Barraquer Barcelona, Spain. A retrospective quasi-experimental, before and after study. Patients who developed high astigmatism or ectasia in the graft-host junction after PK were treated with wedge resection. The following variables were studied before the surgery, 1-year after and at the final visit: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive and topographic astigmatism and spherical equivalent. Vectorial analysis of the astigmatism changes was performed. Fifty-one eyes were included with a mean follow-up of 4.19 ± 3.09 years. Mean refractive astigmatism was 11.47 ± 3.57 diopters (D) pre-operatively and 4.79 ± 3.32 D at the final follow-up (p < 0.001). The mean centroid changed from 2.65 ± 11.82 D at 23 degrees preoperatively to 0.35 ± 5.86 D at 127 degrees postoperatively. Concerning spherical equivalent, the mean preoperative value was -3.10 ± 4.15 D and the mean postoperative value was -1.55 ± 3.41 D (p = 0.002). Mean pre-operative and final follow-up UDVA were 1.25 ± 0.27 and 0.84 ± 0.50 (p < 0.001). Mean Pre-op and final follow-up CDVA were 0.27 ± 0.19 and 0.24 ± 0.24. Wedge resection is a useful surgical procedure to correct high astigmatism. It is a safe technique with moderate efficacy and may be considered as initial procedure of choice in high astigmatism due to long-term ectasia in the graft-host junction after PK for keratoconus.

Corneal endothelial ring following the implantation of toric implantable collamer lenses with a central hole: a case report

BackgroundTo report a case of a corneal endothelial ring after toric implantable collamer lens (TICL, V4C) implantation in the right eye of a patient.Case presentationA 36-year-old woman with refractive errors of -8.00 DS/-2.00 DC * 8° in the right eye and − 6.50 DS/-1.75 DC * 177° in the left eye developed a corneal endothelial ring in the right eye on the first day after receiving TICLs implantation for treatment of high myopic astigmatism, which has not been previously reported as a complication of ICLs implantation. At 1 day postoperatively, the uncorrected distance visual acuity (UDVA) was 20/16, the intraocular pressure as measured by non-contact tonometry was 16.9 mmHg, and the vault as measured by anterior segment optical coherence tomography was 1238 μm. The eye was quiet and there was no unusual anterior chamber reaction. However, slit-lamp examination revealed an endothelial annular lesion of approximately 0.4 mm in diameter in the central part of the cornea, which was gray-white in color. The shape of the ring was the same as that of the central hole of the TICL. Specular microscopy showed that the mean endothelial cell density (ECD) of the ring significantly decreased to 1442 ± 263 cells/mm2, while the other part was still normal (2852 ± 103 cells/mm2). After 9 days of corticosteroid treatment and intense lubrication, the patient had a clear cornea, increased ECD (1532 ± 653 cells/mm2), and a good UDVA (20/16).ConclusionThis case suggests that a few hours after ICL V4C implantation, with a large vault, corneal displacement caused by an air puff would make the endothelium close to or even contact the ICL, producing a corneal endothelial ring. After ruling out various possible factors, we speculated that the endothelial ring was developed due to the non-contact tonometer air puff before slit-lamp evaluation, and this phenomenon was recorded by Corvis, which confirmed that the cornea could come in contact with the ICL due to gas shock. This “contact” may cause transient corneal endothelial damage.

Short-term clinic observation of misalignment and rotational stability after implantable collamer lens implantation.

We aimed to investigate misalignment (tilt and decentration) and rotational stability of the implantable collamer lens V4c 6months after implantation and to explore the potential risk factors associated with postoperative misalignment and rotation. A total of 36 eyes of 36 patients with high myopia and myopic astigmatism who underwent implantable collamer lens V4c implantation were included in this study. Tilt, decentration, and rotation of the implantable collamer lens were assessed postoperatively at l week, 1month, 3months, and 6months. Correlation analysis was used to identify the potential risk factors for implantable collamer lens tilt, decentration, and rotation at 6months postoperatively. Higher-order aberration was measured to evaluate the effect of implantable collamer lens misalignment on visual quality at pupil diameters of 4.0mm and 6.0mm. The tilt and decentration at the last follow-up were 2.43 ± 1.35° and 0.278 ± 0.160mm, respectively. There was a significant positive correlation between tilt and decentration (r = 0.31, P = 0.046). No significant correlation was detected between implantable collamer lens decentration and internal higher-order aberrations (P > 0.05). The degree of implantable collamer lens rotation (3.11 ± 2.00°) was significantly associated with the vault (r = - 0.422, P = 0.01), while it was positively associated with the preoperative anterior chamber depth (r = 0.36, P = 0.034). No significant correlation was found between postoperative astigmatism and rotation (r = - 0.07, P = 0.351). The implantable collamer lens V4c provides relatively stable misalignment and rotation after implantation. The ICL lens vault is a potential risk factor for postoperative implantable collamer lens rotation. The absolute value of decentration and tilt was relatively small, which showed no correlation with internal higher-order aberration in short-term observation.

Case report: simultaneous femtosecond laser astigmatic keratotomy and toric intraocular lens implantation in femtosecond laser-assisted cataract surgery in a patient with surgically induced high corneal astigmatism

Case report: simultaneous femtosecond laser astigmatic keratotomy and toric intraocular lens implantation in femtosecond laser-assisted cataract surgery in a patient with surgically induced high corneal astigmatism

Changes in Light Disturbance Analyzer Evaluation in SMILE for High Myopia and Astigmatism.

To study the objective change in light disturbance around a glare source using the Light Disturbance Analyzer (LDA) (Binarytarget Lda) and correlate this with the validated subjective quality of vision (QoV) questionnaire in small incision lenticule extraction (SMILE) for high compound myopic astigmatism. This was a prospective study recruiting 114 patients undergoing SMILE with attempted spherical equivalent refraction (SEQ) correction from -9.00 to -13.00 diopters (D), and cylinder up to 5.00 D. The LDA was used before and 3 and 12 months after surgery to evaluate the Light Disturbance Area, Light Disturbance Index, Best Fit Circle Radius, and Best Fit Circle Irregularity. Patients completed the Rasch-validated QoV questionnaire before and 12 months after surgery. Correlation analysis was performed between the LDA parameters and the QoV frequency, severity, and bothersomeness for halos and starbursts. At 12 months, there was a non-statistically signifcant change of 11.9% for Light Disturbance Area and Light Disturbance Index and 6.5% for Best Fit Circle Radius. There was an increase of 81.9% for Best Fit Circle Irregularity (P = .017). Light Disturbance Area, Light Disturbance Index, and Best Fit Circle Radius correlated with bothersomeness for QoV halos, and with frequency, severity and bothersomeness for QoV star-bursts (P < .05), albeit with a low correlation coefficient (R2 < 0.13). There was no correlation between increase in Best Fit Circle Irregularity and the halo and starburst scores from the QoV questionnaire. LDA Best Fit Circle Irregularity was found to increase following high myopic SMILE. Other LDA parameters appeared to increase, but a much larger sample would be required to find statistical significance. The change in LDA parameters was only weakly correlated with QoV halo and starburst metrics, representing the wide variation in inter-subject perception. [J Refract Surg. 2022;38(11):725-732.].

Postoperative astigmatic considerations in manual small-incision cataract surgery - A review.

Cataract remains a major cause of visual impairment worldwide including in India. The sutureless manual small-incision cataract surgery (MSICS) as an alternative to phacoemulsification, gives equivalent visual results at lower expenses. Still the procedure is often discredited for higher astigmatism due to the larger size of the incision. High astigmatism is an important cause of poor uncorrected visual acuity after cataract surgery. However, there are enough studies in the literature to prove that surgically induced astigmatism (SIA) can be minimized and also eliminated by adopting appropriate wound construction techniques during surgery. Even pre-existing astigmatism if any can be neutralized by changing wound architecture during surgery. Here, we review the various techniques of scleral tunnel construction described in the literature to care for postoperative astigmatism in MSICS.

Evaluation of the Anterior Chamber Parameters by Pentacam after Toric Implantable Phakic Contact lens (IPCL) Implantation in Moderate to High Myopia with Astigmatism

Background: The toric IPCL is posterior phakic intraocular lens used for correction of moderate to high myopia with astigmatism, but after the implantation, there were changes in the parameters of the anterior chamber (AC). Purpose: The purpose of this study is to assess the parameters of the AC and lens vault after toric IPCL in patients with moderate to high myopia with astigmatism by Pentacam. Patients and Methods: In a prospective interventional case series, 30 eyes with moderate to high myopia with astigmatism were treated with toric IPCL implantation. Pentacam was done preoperatively, after 1 month, 3 months and 6 months of toric IPCL implantation for evaluation of the AC parameters as the angle of the anterior chamber (ACA), depth of the anterior chamber (ACD) and volume of the anterior chamber (ACV). Also, the lens vault and intraocular pressure (IOP) were evaluated. Results: The ACD was 3.3±0.1 mm preoperatively and changed to 2.5±0.1 mm after 1 month and remained stable at 3 and 6 months postoperatively (p-value =0.001). The ACV was 198.06±25.02 mm3 preoperatively and reduced to 131.5±20.7, 131.8±21.4 and 131.5±20.2 mm3 after 1 month, 3 months and 6 months, respectively(p-value =0.001). The ACA was 42.9±4.1 preoperatively and changed to 26.7±4.3, 26.4±4.2 and 26.7±4.9 after 1 month, 3 months and 6 months, respectively (p-value =0.001). The vault was 458±126.2 um after 1 month, 461±129.6 um after 3 months and 464.6±130.6 um after 6 months (p-value =0.005). The IOP was slightly high during the first month, then reduced to a level near the preoperative values during the second and third follow-up. Conclusion: The Pentacam was a useful tool for follow up of the AC parameters after toric IPCL implantation in patients with moderate to high myopia astigmatism.

Effect of keratometric astigmatism on visual outcomes following small incision lenticule extraction.

To investigate the influence of keratometric astigmatism on visual outcomes following small incision lenticule extraction (SMILE). Eighty eyes undergoing SMILE for myopia correction were classified into two groups based on preoperative keratometric astigmatism: low keratometric astigmatism (LA) and high keratometric astigmatism (HA) groups. Refractive outcomes, vector components, and changes in higher order aberrations (HOAs) were evaluated preoperatively and 6 months postoperatively. At the postoperative 6-month visit, no significant difference was observed in the decentered distance between the HA and LA groups (HA: 0.17 ± 0.08 mm, LA: 0.16 ± 0.08 mm, P = 0.189). No significant differences in the correction index (P = 0.481), absolute angle of error (P = 0.104), or index of success (P = 0.147) were observed between the two groups. There was no significant difference in the induction of corneal aberrations between the two groups. Furthermore, there were no significant associations between the decentered distance and the vector components of astigmatic correction or induction of higher-order aberration in the HA group (P ≥ 0.294, P ≥ 0.112) or the LA group (P ≥ 0.323, P ≥ 0.080). SMILE for high keratometric astigmatism could achieve comparable treatment centration and visual quality to that of low keratometric astigmatism.

Propensity-matched comparison of postoperative stability and visual outcomes of toric intraocular lens with or without a capsular tension ring and updated meta-analysis.

To assess the contribution of capsular tension ring (CTR) to postoperative stability and visual outcomes of a plate-haptic toric intraocular lens (IOL). This prospective cohort study was performed among patients underwent toric IOL (AT TORBI 709M) implantation with or without CTR at the Eye and ENT hospital between April 2020 and November 2021. Propensity score matching (PSM) was performed to balance baseline factors. Postoperatively, uncorrected distance visual acuity (UCVA) and residual astigmatism, as well as IOLs' rotation, tilt, and decentration, were analyzed. Grouped multiple linear regression analysis was used to model predictive factors of rotation in each group. Additionally, a meta-analysis of data from 4 publications (284 eyes) and current study was performed to evaluate the effect of CTR co-implantation on toric IOL rotation. After PSM, 126 eyes from each group were included for further analysis. Postoperatively, UDVA was 0.31 ± 0.38 logMAR and 0.27 ± 0.36 logMAR in the CTR and NCTR groups, respectively (P = 0.441), and residual astigmatism was 0.75 ± 0.52 D and 0.86 ± 0.65 D, respectively (P = 0.139). The rotation of toric IOL was significantly smaller in the CTR group than in the NCTR group (4.63 ± 6.27 vs. 10.93 ± 16.05 degrees, P < 0.001). The regression models of the two groups and the coefficients of LT were significantly different (P < 0.001 and P = 0.001, respectively). Furthermore, the meta-analysis confirmed that CTR co-implantation reduced toric IOL rotation (MD, - 1.59; 95% CI, - 3.10 to - 0.09; P = 0.038). CTR enhances rotational stability of toric IOL by reducing the impact of LT, and CTR co-implantation is recommended in patients with lens thickness (LT) ≥ 4.5mm, white-to-white (WTW) ≥ 11.6mm, or high preexisting astigmatism.

A Comparative Study of Refraction in Skiascopy and Autorefractometry before and after Application of Cycloplegics

Purpose: To evaluate the difference of refractive errors measured by skiascopy and autorefractometry before and after application of cycloplegics according to age, the degree of myopia and of astigmatism.Methods: School myopia (384 eyes of 227 persons) were measured by skiascopy and autorefractometry before and after instillation of cycloplegics, and each refractive error was compared. According to age, it was divided into elementary school group (236 eyes), middle and high school group (54 eyes), and university group (94 eyes). Myopic spherical power was classified into mild group with power -2.0 diopter (D) or less (119 eyes), moderate group with -2.0 D or more and -6.0 D or less (178 eyes), and high group with greater than -6.0 D (87 eyes). Astigmatism is divided into mild group with less than -2.0 D (296 eyes) and high group with greater than -2.0 D (88 eyes).Results: The post-cycloplegics spherical and spherical equivalent refractive values by the autorefractometry and the skiascopy were measured to be lower than manifest autorefractometry, and the astigmatic power after cycloplegic refraction was measured to be high, but there is no statistically significant difference (&lt;i&gt;p&lt;/i&gt; &gt; 0.05). In the case of elementary school, middle and high school, the value of spherical and astigmatism increased significantly compared to the university group, but there is no statistically significant difference (&lt;i&gt;p&lt;/i&gt; &gt; 0.05). The difference of refractive errors between the spherical and the spherical equivalent value increased significantly as the degree of myopia increased. The value of difference between mild and high group of astigmatism was significantly increased in high group compared to mild group.Conclusions: It should be necessary to accurately measure to wear glasses in school myopia with the younger, the more myopia is greater than -6.0 D, and high astigmatism with more than -2.0 D.

Long-Term Outcome of Corneal Collagen Crosslinking with Riboflavin and UV-A Irradiation for Keratoconus*

Purpose To evaluate long-term outcomes of corneal collagen crosslinking (CXL) using riboflavin and UV-A irradiation and to determine when to repeat CXL. Methods In this retrospective consecutive interventional case series 131 eyes of 131 patients (95 male, 36 female, mean age 29.7 ± 11.4 years) between 2006 and 2016 received standard CXL (Dresden protocol, epithelium-off) for progressive keratoconus. Corrected distance visual acuity (CDVA) and corneal tomography (K1, K2, K max) were repeatedly recorded 1 year (n = 103 eyes) to 10 years (n = 44) postoperatively. Only one eye per patient was included. Paired t-test or Wilcoxon matched-pairs signed rank test was used for parametric and nonparametric data, respectively. Results 1–3 years preoperatively, median K2 significantly increased by 1.1 D (p < 0.001). Postoperatively, median K2 increased by 0.1 D after 1 year, then decreased over the remaining postoperative period by 0.85 D (p = 0.021). K max fluctuated without significant change. Median apical corneal thickness decreased by 16 µm (p = 0.012) after 5 years and then returned to preoperative values. Mean CDVA showed a significant improvement (decrease in logMAR 0.08 after 10 years, p = 0.010). CXL non-responders, defined by a postoperative increase in K max>2 D, increased from 16% after 5 to 33% after 10 years. Risk factors for non-response were young age, high astigmatism (>4.3 D), thin cornea (<480 µm), poor initial visual acuity (CDVA ≥0.3 D), and atopic dermatitis. 4 eyes were re-treated 3–4 years after first CXL without complications and keratoconus stabilized thereafter. Conclusions CXL can slow or stop keratoconus progression. However, as the number of responders declines after 5 years, especially patients with risk factors may require re-treatment.

Refractive error in unilateral Duane syndrome

To investigate whether chronic co-contraction of the medial and lateral rectus muscles leads to higher against-the-rule astigmatism in affected versus fellow eyes in Duane syndrome. A database of 4,103 patients of Dr. Arthur Jampolsky was queried for diagnosis of Duane syndrome. Inclusion criteria were unilateral Duane syndrome and complete data set. Refractive error was compared between Duane and fellow eyes. A total of 84 patients with unilateral Duane syndrome were identified. The spherical equivalent of Duane eyes and fellow eyes was similar (0.4 vs. 0.2 [P = 0.14]). Mean cylinder power was higher in Duane eyes compared to fellow eyes (0.7 vs 0.4 [P = 0.0003]). There was modest evidence of more against-the-rule astigmatism in Duane eyes compared to fellow eyes (P = 0.04) but no difference for with-the-rule astigmatism (P = 0.83). Duane compared to fellow eyes were, however, significantly more likely to have oblique astigmatism (P = 0.004) or any astigmatism at all (P = 0.0005). Duane eyes compared to fellow eyes had higher astigmatism that was more likely to be oblique. Our study lends support to the hypothesis that extraocular muscles may influence refractive error.

Refractive surgery after deep anterior lamellar keratoplasty: a review of the literature.

The main objective of this work is to present an updated review of the different surgical procedures for the correction of residual refractive errors following deep anterior lamellar keratoplasty (DALK) surgery. A review of the literature was conducted using PubMed, Web of Science, and Scopus databases. The search was conducted in January 2022 and was limited to articles published in peer-reviewed journals. The information extracted from each publication included sample size, mean follow-up time, pre- and post-operative uncorrected (UDVA) and corrected distance visual acuity (CDVA), pre- and post-operative refraction and spherical equivalent (SE), safety and efficacy indexes and complications. Residual ametropias, mainly high astigmatism and myopia, and the resulting anisometropia are likely to occur following DALK. They become a limiting factor and may lead to unsatisfactory visual restoration, therefore affecting patients' quality of vision and life. Alternative surgical interventions may be required to treat this residual ametropia, such as corneal refractive surgery or intraocular lens implantation. A total of 47 relevant articles were studied in detail. Different refractive surgery techniques have been shown to be effective and safe for the correction of ametropia following the DALK procedure and to improve the patient's quality of vision, although more research is needed to confirm long-term results. The final refractive technique will depend on different factors, such as the amount of ametropia, the condition of the cornea or the patient's individual needs, economics, and occupational demands.

Comparison of the Functional Optical Zone in Eyes With High Myopia With High Astigmatism After SMILE and FS-LASIK.

To compare the functional optical zone (FOZ) in eyes with high myopia with high astigmatism after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). In total, 45 eyes of 45 patients with high myopia with astigmatism greater than 2.00 diopters (D) who underwent SMILE or FS-LASIK were enrolled. The FOZ, optical zone decentration, and corneal aberrations were analyzed using Scheimpflug imaging. These values were then compared between the two groups 6 months postoperatively. No postoperative complications were observed during follow-up. The mean FOZ diameter was 5.03 ± 0.31 mm for the FS-LASIK group and 5.24 ± 0.27 mm for the SMILE group (P = .007), corresponding to reductions of 1.18 ± 0.23 and 1.01 ± 0.21 mm, respectively, compared with the programmed optical zone (POZ) (P = .013). A significant difference was noted in the FOZ on the short axis between the two groups (P = .002), whereas no significant difference was observed on the long axis (P = .088). The FOZ area in the FS-LASIK and SMILE groups was 65.39 ± 6.14% and 70.09 ± 5.46% of the POZ area, respectively (P = .010). There was no significant difference in decentration between the two groups (0.29 ± 0.13 mm for the FS-LASIK group vs 0.30 ± 0.13 mm for the SMILE group, P = .798). A significant increase in spherical aberration was observed in the FS-LASIK group (P < .001). However, the induction of vertical coma was higher in the SMILE group than in the FS-LASIK group (P = .002). Eyes with high myopia with high astigmatism following SMILE achieved a larger FOZ and less spherical aberration but a larger vertical coma introduction than following FS-LASIK. [J Refract Surg. 2022;38(9):595-601.].

Correction of high astigmatism with toric intraocular lens in eyes with corneal transplant.

To evaluate the results of toric intraocular lens (IOL) implantation during cataract surgery in eyes with high regular astigmatism associated with prior penetrating keratoplasty (PK). A retrospective data analysis of patients with prior PK, who underwent uncomplicated cataract surgery with hydrophobic toric single piece IOL (EyeCryl Toric®, Biotech Vision Care, Luzern, Switzerland). A total of 18 eyes of 18 patients were included in the study. The mean age was 53.4 ± 12.4 (25-70) years. The mean follow-up period was 15.5 (4-24) months. The mean best corrected visual acuity (BCVA) significantly increased from 1.36 ± 1.0 logMAR to 0.31 ± 0.17 logMAR (p < .001) pre- and post-operative 4 weeks, respectively. There was no significant change in mean BCVA during follow-up; mean BCVA was 0.32 ± 0.17 logMAR at the last visit. The mean pre-operative topographic astigmatism was 6.52 ± 1.80 diopters (D). The mean manifest refraction astigmatism was decreased from 6.55 ± 1.62 D to 2.80 ± 1.43 D (p˂0.001). The mean Surgically induced astigmatism (SIA) was 3.74 ± 0.77 D according to vector analysis. There was no patient with graft rejection or failure, the mean endothelial cell loss rate was 12.75 ± 3.76% (7-17%). There was no patient requiring IOL reposition. Toric IOL implantation during cataract surgery provides an option to correct astigmatism in post-PK eyes with high regular astigmatism. When appropriate patients are selected it is a safe method to achieve significant improvements in visual acuity and astigmatism.

Femtosecond laser-assisted arcuate keratotomy for the management of corneal astigmatism in patients undergoing cataract surgery: Comparison with conventional cataract surgery.

PurposeTo assess the effects of femtosecond laser arcuate keratotomy with femtosecond laser-assisted cataract surgery in the management of corneal astigmatism, compared with conventional phacoemulsification cataract surgery.DesignRetrospective comparative interventional case series.MethodsA total of 2,498 eyes of consecutive patients who presented with 3.00 diopters (D) or under of astigmatism were included. The patients were treated with conventional phacoemulsification cataract surgery (conventional group) and femtosecond laser arcuate keratotomy with femtosecond laser-assisted cataract surgery (femtosecond group).ResultsSurgically induced astigmatism (SIA) was higher in the femtosecond group than the conventional group (0.215, p < 0.001). Difference vector (DV) was lower in the femtosecond group (-0.136, p < 0.001). The cut-off value of the overcorrection in the femtosecond group was 0.752 D of target induced astigmatism (TIA). For patients with TIA 0.75 D or under, DV and the value of index of success (TIA into DV) were significantly higher in the femtosecond group (p = 0.022 and < 0.001). The overcorrection ratios were 48.8% in the conventional and 58.9% in the femtosecond group. (p < 0.001). For patients with TIA over 0.75 D, SIA and correction index (TIA into SIA) was higher in femtosecond group (0.310 and 0.250, p < 0.001 and < 0.001, respectively). Absolute angle of error was 20.612 ± 18.497 in the femtosecond group and higher than the conventional group (2.778, p = 0.010).ConclusionFemtosecond laser arcuate keratotomy in cataract surgery was effective in SIA between 0.75 to 3.00 D of corneal astigmatism. However, the overcorrection in the lower astigmatism and angle of error in the higher astigmatism were due to the postoperative corneal astigmatism not decreasing as much as SIA. Overcoming these challenges will lead to better management of corneal astigmatism.