The Impact of Different Optical Zone Diameter on Corneal Astigmatism Correction Using Femtosecond Laser Corneal Relaxing Incisions: 8 mm vs 9 mm.

PURPOSE: To compare the impact of 8 mm versus 9 mm optical zone (OZ) diameters on corneal astigmatism correction and to evaluate the impact of incision depth percentage after femtosecond laser corneal relaxing incisions (CRIs) combined with cataract surgery. METHODS: Thirty-nine eyes from 39 patients were enrolled and randomly assigned to two groups based on the OZ diameter: 8 mm and 9 mm. Corneal astigmatism and CRI depth were measured using Pentacam and anterior segment optical coherence tomography. Vector analysis was performed using Alpins method. RESULTS: In the 8 mm group, postoperative corneal astigmatism was reduced by 0.77 ± 0.61 diopters (D), significantly greater than the reduction of 0.42 ± 0.40 D in the 9 mm group (p < 0.05). The 8 mm group exhibited greater surgically induced astigmatism (SIA), net corneal changes, and a smaller angle of error (AE) (p < 0.05). At 3 months postsurgery, the correction index (CI) values were 0.84 ± 0.39 for the 8 mm group, exceeding the 0.52 ± 0.32 observed in the 9 mm group (p < 0.05). The mean incision depth percentage was significantly higher in the 9 mm group (79.30 ± 10.76%) compared to the 8 mm group (72.58 ± 8.73%) (p < 0.05). In the 8 mm group, CI values closer to 1.00 were associated with lower percentages of incision depth. CONCLUSIONS: CRIs with an 8 mm OZ diameter demonstrated superior efficacy in correcting corneal astigmatism with shallower incision depths compared to those with a 9 mm diameter.

Meridional Amblyopia and Spectacle Correction: A Prospective Interventional Study of Children Aged 4-11 Years.

Background Amblyopia, often linked to high astigmatism in children, presents challenges in understanding the contributing factors and visual outcomes. Methods A total of 132 samples were included in this prospective pre- and post-interventional study using the purposive sampling technique. Descriptive statistics were applied for age, gender, uncorrected visual acuity, corrected visual acuity, type, and magnitude of astigmatism. A repeated measure ANOVA was used, and a paired t-test was also done for groups with corrected visual acuity in meridional amblyopia at two follow-ups spaced six months apart. Logistic regression was used to identify the association between astigmatism types and patients' recovery from amblyopia after intervention. Results The age of participants was 4-11 years with meridional amblyopia. Initial findings showed a mean uncorrected visual acuity of 0.73 LogMAR in the right eye (RE) and 0.71 LogMAR in the left eye (LE), improving significantly to 0.35 LogMAR post-intervention in both eyes. The calculated mean difference between the first correction and the first follow-up was 0.12 and 0.13 LogMAR, while it was 0.20 and 0.21 LogMAR in the RE and LE, respectively, at the second follow-up. Spherical refractive errors averaged +0.93 DS, with mean cylindrical refraction indicating predominant with-the-rule corneal astigmatism (-3.46 DS). We observed a significant improvement in visual acuity (p-value < 0.001) and an increase in the magnitude of cylindrical prescription (p-value < 0.001). However, astigmatism types are not associated with response to therapy. Conclusion The study concluded that early detection of meridional amblyopia and early intervention with spectacles significantly improve visual acuity.

Evaluating the Accuracy of Artificial Intelligence (AI)-Generated Illustrations for Laser-Assisted In Situ Keratomileusis (LASIK), Photorefractive Keratectomy (PRK), and Small Incision Lenticule Extraction (SMILE).

PURPOSE: To utilize artificial intelligence (AI) platforms to generate medical illustrations for refractive surgeries, aiding patients in visualizing and comprehending procedures like laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE). This study displays the current performance of two OpenAI programs in terms of their accuracy in common corneal refractive procedures. METHODS: We selected AI image generators based on their popularity, choosing Decoder-Only Autoregressive Language and Image Synthesis 3 (DALL-E 3) for its leading position and Medical Illustration Master (MiM) for its high engagement. We developed six non-AI-generated prompts targeting specific outcomes related to LASIK, PRK, and SMILE procedures to assess medical accuracy. We generated images using these prompts (18 total images per AI platform) and used the final images produced after the sixth prompt for this study (three final images per AI platform). Human-created procedural images were also gathered for comparison. Four experts independently graded the images, and their scores were averaged. Each image was evaluated with our grading system on "Legibility," "Detail & Clarity," "Anatomical Realism & Accuracy," "Procedural Step Accuracy," and "Lack of Fictitious Anatomy," with scores ranging from 0 to 3 per category allowing 15 points total. A score of 15 points signifies excellent performance, indicating a highly accurate medical illustration. Conversely, a low score suggests a poor-quality illustration. Additionally, we submitted the same AI-generated images back into Chat Generative Pre-Trained Transformer-4o (ChatGPT-4o) along with our grading system. This allowed ChatGPT-4o to use and evaluate both AI-generated and human-created images (HCIs). RESULTS: In individual category scoring, HCIs significantly outperformed AI images in legibility, anatomical realism, procedural step accuracy, and lack of fictitious anatomy. There were no significant differences between DALL-E 3 and MiM in these categories (p>0.05). In procedure-specific comparisons, HCIs consistently scored higher than AI-generated images for LASIK, PRK, and SMILE. For LASIK, HCIs scored 14 ± 0.82 (93.3%), while DALL-E 3 scored 4.5 ± 0.58 (30%) and MiM scored 4.5 ± 1.91 (30%) (p<0.001). For PRK, HCIs scored 14.5 ± 0.58 (96.7%), compared to DALL-E 3's 5.25 ± 1.26 (35%) and MiM's 7 ± 3.56 (46.7%) (p<0.001). For SMILE, HCIs scored 14.5 ± 0.68 (96.7%), while DALL-E 3 scored 5 ± 0.82 (33.3%) and MiM scored 6 ± 2.71 (40%) (p<0.001). HCIs significantly outperformed AI-generated images from DALL-E 3 and MiM in overall accuracy for medical illustrations, achieving scores of 14.33 ± 0.23 (95.6%), 4.93 ± 0.69 (32.8%), and 5.83 ± 0.23 (38.9%) respectively (p<0.001). ChatGPT-4o evaluations were consistent with human evaluations for HCIs (3 ± 0, 2.87 ± 0.23; p=0.121) but rated AI images higher than human evaluators (2 ± 0 vs 1.07 ± 0.73; p<0.001). CONCLUSION: This study highlights the inaccuracy of AI-generated images in illustrating corneal refractive procedures such as LASIK, PRK, and SMILE. Although the OpenAI platform can create images recognizable as eyes, they lack educational value. AI excels in quickly generating creative, vibrant images, but accurate medical illustration remains a significant challenge. While AI performs well with text-based actions, its capability to produce precise medical images needs substantial improvement.

Innovations and Outcomes in Astigmatism Correction During Cataract Surgery: A Comprehensive Review.

Astigmatism, a prevalent refractive error caused by an irregular curvature of the cornea or lens, can significantly affect visual acuity and the quality of life. Correcting astigmatism during cataract surgery is essential for achieving optimal postoperative visual outcomes. This comprehensive review examines recent innovations in astigmatism correction methods and their impact on cataract surgery. It provides an in-depth analysis of advancements such as toric intraocular lenses (IOLs), femtosecond laser-assisted cataract surgery (FLACS), and new IOL technologies designed to address astigmatism with greater precision. The review also evaluates clinical outcomes, including visual acuity improvements, patient satisfaction, and safety considerations associated with these innovations. Additionally, it explores the cost-effectiveness of various techniques and highlights emerging trends and future directions in the field. By synthesizing current evidence, this review aims to offer valuable insights for clinicians and inform best practices in astigmatism management during cataract surgery.

Can AI Predict the Magnitude and Direction of Ortho-K Contact Lens Decentration to Limit Induced HOAs and Astigmatism?

Background: The aim is to investigate induced higher-order aberrations (HOA)s and astigmatism as a result of non-toric ortho-k lens decentration and utilise artificial intelligence (AI) to predict its magnitude and direction. Methods: Medmont E300 Video topographer was used to scan 249 corneas before and after ortho-k wear. Custom-built MATLAB codes extracted topography data and determined lens decentration from the boundary and midpoint of the central flattened treatment zone (TZ). An evaluation was carried out by conducting Zernike polynomial fittings via a computer-coded digital signal processing procedure. Finally, an AI-based machine learning neural network algorithm was developed to predict the direction and magnitude of TZ decentration. Results: Analysis of the first 21 Zernike polynomial coefficients indicate that the four low-order and four higher-order aberration terms were changed significantly by ortho-k wear. While baseline astigmatism was not correlated with lens decentration (R = 0.09), post-ortho-k astigmatism was moderately correlated with decentration (R = 0.38) and the difference in astigmatism (R = 0.3). Decentration was classified into three groups: ≤0.50 mm, reduced astigmatism by -0.9 ± 1 D; 0.5~1 mm, increased astigmatism by 0.8 ± 0.1 D; >1 mm, increased astigmatism by 2.7 ± 1.6 D and over 50% of lenses were decentred >0.5 mm. For lenses decentred >1 mm, 29.8% of right and 42.7% of left lenses decentred temporal-inferiorly and 13.7% of right and 9.4% of left lenses decentred temporal-superiorly. AI-based prediction successfully identified the decentration direction with accuracies of 70.2% for right and 71.8% for left lenses and predicted the magnitude of decentration with root-mean-square (RMS) of 0.31 mm and 0.25 mm for right and left eyes, respectively. Conclusions: Ortho-k lens decentration is common when fitting non-toric ortho-k lenses, resulting in induced HOAs and astigmatism, with the magnitude being related to the amount of decentration. AI-based algorithms can effectively predict decentration, potentially allowing for better control over ortho-k fitting and, thus, preferred clinical outcomes.

Optimizing IOL Calculators with Deep Learning Prediction of Total Corneal Astigmatism.

Background/Objectives: This study aims to identify the most accurate regression model for predicting total corneal astigmatism (TCA) from anterior corneal astigmatism (ACA) and to fine-tune the best model's architecture to further optimize predictive accuracy. Methods: A retrospective review of 19,468 eyes screened for refractive surgery was conducted using electronic medical records. Corneal topography data were acquired using the Pentacam HR. Various types (7) and subtypes (21) of regression learners were tested, with a deep neural network (DNN) emerging as the most suitable. The DNN was further refined, experimenting with 23 different architectures. Model performance was evaluated using root mean squared error (RMSE), R2, average residual error, and circular error. The final model only used age, ACA magnitude, and ACA axis to predict TCA magnitude and axis. Results were compared to predictions from one of the leading TCA prediction formulas. Results: Our model achieved higher performance for TCA magnitude prediction (R2 = 0.9740, RMSE = 0.0963 D, and average residual error = 0.0733 D) compared to the leading formula (R2 = 0.8590, RMSE = 0.2257 D, and average residual error = 0.1928 D). Axis prediction error also improved by an average of 8.1° (average axis prediction error = 4.74° versus 12.8°). The deep learning approach consistently demonstrated smaller errors and tighter clustering around actual values compared to the traditional formula. Conclusion: Deep learning techniques significantly outperformed traditional methods for TCA prediction accuracy using the Pentacam HR. This approach may lead to more precise TCA calculations and better IOL selection, potentially enhancing surgical outcomes.

Risks of Hyperopia, Myopia, Astigmatism, and Strabismus in Children With Autism Spectrum Disorder: A Nationwide, Population-Based Cohort Study.

OBJECTIVE: In this population-based cohort study, we compared the risks of incident hyperopia, myopia, astigmatism, and strabismus between children with autism spectrum disorder (ASD) and children without ASD. METHODS: This study included children who were born in Taiwan at any time between 2004 and 2017. Data were collected from the Taiwan Maternal and Child Health Database. We included 20,688 children with ASD and 2,062,120 matched controls to estimate the risks of incident hyperopia, myopia, astigmatism, and strabismus. Cox proportional hazards regression models were constructed for risk assessment. The models were adjusted for sex, calendar year of birth, and gestational age at birth. Statistical significance was determined by calculating adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). RESULTS: Children with ASD had higher risks of incident hyperopia (aHR: 1.78; 95% CI: 1.70-1.86), myopia (aHR: 1.27; 95% CI: 1.24-1.30), astigmatism (aHR: 1.51; 95% CI: 1.46-1.56), and strabismus (aHR: 2.18; 95% CI: 2.05-2.32) than did those without it. CONCLUSION: Clinicians should screen children with ASD for potential ophthalmic conditions. Further studies are required to elucidate the mechanisms underlying the associations between ASD and ophthalmic diseases. The roles of types and severities of ASD symptoms in detecting ophthalmic disease also requires further study.

The outcomes of first-generation (visumax 500) and second-generation (Visumax 800) keratorefractive lenticule extraction surgeries for astigmatism.

To evaluate the efficiency, predictability, and residual astigmatism between first- and second-generation keratorefractive lenticule extraction (KLEx) surgeries in a prominent astigmatism population. A retrospective cohort study was conducted, and individuals who underwent first- and second-generation KLEx surgeries were enrolled. A total of 31 and 35 eyes were categorized into first and second KLEx groups, respectively. Visual acuity, refraction, topographic parameters, and surgical indices were recorded. Independent t tests were used to compare the postoperative uncorrected distance visual acuity (UDVA), spherical equivalent (SE), and residual astigmatism between the two groups. The difference in UDVA was not significant three months after KLEx surgery (P = 0.509), and the SEs three months after surgery also presented similar values between the two groups (P = 0.552). The first KLEx group demonstrated greater residual astigmatism than did the second KLEx group throughout the three-month follow-up period (all P < 0.05). The values of surgically induced astigmatism (SIA), difference vector (DV), magnitude of error (ME) and correction index (CoI) were significantly better in the second KLEx group via vector analysis (all P < 0.05). Old age, high steep keratometry (K), high topographic cylinder, large angle kappa, and a small optic zone were correlated with greater residual astigmatism in the first KLEx group (all P < 0.05), whereas only a small optic zone was significantly correlated with greater residual astigmatism in the second KLEx group (P = 0.047). The second-generation KLEx is correlated with a lower risk of residual astigmatism.

Intraocular Lens Power and Corneal Topographic Change After Pterygium Surgery: Pterygium Effects on IOL Power Calculation.

PURPOSE: To investigate the impact of pterygium excision on intraocular lens (IOL) power calculation and corneal astigmatism. DESIGNS: Prospective cohort study METHODS: We enrolled 30 eyes with primary pterygium that underwent pterygium excision with a conjunctival autograft. IOL power calculation and keratometry using the IOL Master 700, along with topographic parameters using the Pentacam Scheimpflug topography system, were performed preoperatively and at 1, 3, 6, and 12 months postoperatively. We analyzed correlations between pterygium length/area and IOL power, as well as corneal topographic changes. RESULTS: The mean pterygium length was 2.08 ± 0.58 mm, and the mean area was 6.05 ± 2.41 mm2. One year after pterygium surgery, the calculated IOL power values using all formulas were lower than the preoperative values. Pterygia with a horizontal length of 1.73 mm and an area of 4.45 mm2, and those with a horizontal length of 2.25 mm and an area of 6.95 mm2 created 0.5 D and 1.0 D errors in calculated IOL power, respectively (p<0.001). The calculated IOL power values changed significantly from preoperative to six months postoperatively but did not change significantly from six to 12 months postoperatively. Pterygia with a horizontal length greater than 1.83 mm (p<0.001) and an area greater than 5.1 mm2 (p < 0.001) created a 2.0 D error in anterior corneal astigmatism. CONCLUSIONS: Pterygium causes errors in IOL power calculation, with greater pterygium length/area exerting a larger effect. Cataract surgery with IOL implantation is recommended at least six months after pterygium surgery. In combined case, calculated IOL power should be decreased by 0.5-1.5 D based on the pterygium length/area.

Baseline characteristics of children in the early glasses study.

PURPOSE: The relationship between refractive error at age 1 and the risk of developing amblyopia or accommodative esotropia, and the protection offered by early glasses, is unknown. These are determined in the Early Glasses Study, a prospective, population-based, longitudinal, randomized controlled study. We report baseline findings. METHODS: Healthy children aged 12-18 months were recruited at Children's Healthcare Centres (CHCs) and received an entry orthoptic examination followed by cycloplegic retinoscopy. Children with amblyopia, strabismus, ophthalmic disease or very high refractive error were excluded. Those exceeding the AAPOS 2003 Criteria (> + 3.5D spherical equivalent (SE), > 1.5D astigmatism, > 1.5D anisometropia) were randomized into wearing glasses or not, and are followed-up by research orthoptists. Other children are followed-up by regular vision screening at CHCs and visual acuity is measured in all children at age 4. RESULTS: Parents of 865 children were called, 123 were excluded. Of 742 children enrolled, 601 underwent the entry orthoptic examination at age 14.5 ± 1.7 months. Mean SE was + 1.73 ± 1.18D, astigmatism -0.70 ± 0.44D, anisometropia 0.21D (IQR: 0-0.25). Of 62 (10.3%) children exceeding the Criteria, 52 were randomized into wearing glasses or not. Of 539 other children, 522 are followed up at CHCs. In total, 31 were excluded: 2 had strabismus and amblyopia, 7 strabismus, 2 amblyopia suspect, 1 strabismus suspect, 1 squinting during sinusitis, 4 excessive refractive error, 9 myopia, 2 ptosis, 1 oculomotor apraxia, 1 Duane syndrome, 1 congenital nystagmus. CONCLUSION: Prevalence of strabismus (10/601) was as expected, but prevalence of amblyopia (2/601) was low, suggesting that common amblyopia develops later than generally thought. KEY MESSAGES: What is known • High refractive errors cause amblyopia, but no study has determined the exact relationship between the kind and size of refractive error at age 1 and the risk to develop amblyopia, and assessed the protective effect of glasses in a controlled, population-based, longitudinal study. What is new • At baseline, 601 children received a full orthoptic examination followed by retinoscopy in cycloplegia at the age of 14.5 ± 1.7 months; 10.3% had high refractive error exceeding spherical equivalent > + 3.5D, > 1.5D astigmatism, > 1D oblique astigmatism or > 1.5D anisometropia. • The prevalence of amblyopia was lower (0.3%) than expected, suggesting that most amblyopia develops after the first year of life. • The prevalence of anisometropia, associated with amblyopia in older children, was low (0.8%).

Estimating the astigmatic power of the crystalline lens and eye from ocular biometry.

PURPOSE: To estimate the astigmatic power of the crystalline lens and the whole eye without phakometry using a set of linear equations and to provide estimates for the astigmatic powers of the crystalline lens surfaces. METHODS: Linear optics expresses astigmatic powers in the form of matrices and uses paraxial optics and a 4 × 4 ray transfer matrix to generalise Bennett's method comprehensively to include astigmatic elements. Once this is established, the method is expanded to estimate the contributions of the front and back lens surfaces. The method is illustrated using two examples. The first example is of an astigmatic model eye and compares the calculated results to the original powers. In the second example, the method is applied to the biometry of a real eye with large lenticular astigmatism. RESULTS: When the calculated powers for the astigmatic model eye were compared to the actual powers, the difference in the power of the eye was 0.03 0.13 0.04 T D $$ {\left(0.03\kern0.5em 0.13\kern0.5em 0.04\right)}^{\mathrm{T}}\ \mathrm{D} $$ (where T represents the matrix transpose) and for the crystalline lens, the difference was 0.08 0.29 0.08 T D $$ {\left(0.08\kern0.5em 0.29\kern0.5em 0.08\right)}^{\mathrm{T}}\ \mathrm{D} $$ (power vector format). A second example applies the method to a real eye, obtaining lenticular astigmatism of -5.84 × 175. CONCLUSIONS: The method provides an easy-to-code way of estimating the astigmatic powers of the crystalline lens and the eye.

The Role of 20% Ethanol in Enhancing Pterygium Surgery Outcomes: A Clinical Study.

Introduction Pterygium is an ocular surface disorder characterized by a hyperplastic growth of conjunctiva encroaching over the cornea. It causes redness, watering, and foreign body sensation. Surgical excision is the preferred mode of treatment when there is encroachment over the visual axis, chronic irritation, restricted ocular motility, and cosmetic concerns. Various surgical methods have been adopted for the treatment and to prevent recurrences. This study assessed the effectiveness and safety of 20% ethanol as an adjuvant in pterygium excision with conjunctival autograft implantation, evaluating surgical outcomes. Methods A prospective hospital-based interventional study was conducted among 30 patients with pterygium from August 2022 to December 2023. Patients were evaluated preoperatively for anterior segment, posterior segment, visual acuity, and corneal astigmatism. Pterygium was excised using 20% ethanol as an adjuvant, and conjunctival autograft was placed over the bare sclera without sutures. Patients were evaluated on postoperative days 1, 8, 30, and 90 for graft condition, visual acuity, corneal astigmatism, and associated complications. Results After three months of follow-up, the mean visual acuity improved to LogMAR 0.46±0.35 (p=0.001), which was statistically significant, and the average corneal astigmatism decreased from 3.36±2.87 to 0.87±0.57 (p=0.0001). No recurrence was noted among the participants. Conclusion This study has shown that using 20% ethanol as an adjuvant for pterygium excision facilitated clean dissection of a pterygium from the underlying cornea and the pterygium-induced corneal astigmatism has significantly decreased, which led to progress in vision.

Corneal changes after large (9mm) lateral rectus muscle recession measured with Pentacam®.

Introduction: The aim of this study was to evaluate alterations in corneal astigmatism, axial anterior corneal curvature, anterior chamber depth, and central corneal thickness (CCT) two months after the unilateral recession of lateral rectus muscle in children. Methods: This prospective study included 37 children with intermittent exotropia who would undergo unilateral lateral rectus muscle recession. All measurements were performed using Pentacam®. Comparisons were made between the operated and fellow unoperated eyes, pre- and post-operatively. The assessment was made for changes in the radius of axial curvature on major meridians at 3 and 3.5 mm from the optical corneal center in the mid-peripheral zone. Astigmatism changes of the anterior and posterior corneal surface were calculated using vector analysis software (astigMATIC®). The interaction between age or CCT and postoperative changes in anterior and posterior surface corneal astigmatism were examined with ANOVA model. Results: In the intervention group, changes in anterior and posterior corneal surface astigmatism were statistically significant, with a mean increase of 0.56Dx90 and 0.08Dx87, respectively. In the mid-peripheral corneal zone, an increase was observed in the radius of anterior corneal axial curvature, more evident temporal 3 and 3.5 mm from the corneal center on the horizontal meridian, with corresponding decrease superiorly and inferiorly at 3 and 3.5 mm from the corneal center on the vertical meridian. Discussion: The changes in total astigmatism of the operated eyes are mainly attributed to the anterior corneal surface. These changes are associated with flattening in the 180 meridian of the cornea, leading to a shift to "with-the-rule" astigmatism.

Poverty and Vision: The Effect of Title 1 Status on Vision Screening Referral Rates in School-Aged Children in Western South Dakota.

PURPOSE: Interventions such as eye exams and glasses are used to correct visual problems that may lead to amblyopia, an irreversible decrease in visual acuity. Children with limited access to these interventions are more likely to have unaddressed visual problems that can lead to amblyopia or negatively impact school performance. This study compared vision screening results of children in schools with Title 1 or Non-Title 1 designation to investigate the link between poverty and vision. METHODS: Data from KidsFIRST vision screenings conducted with the SPOTTM photoscreener performed in Rapid City Area elementary schools were compared across multiple parameters. Students were referred for eye examinations based on identifying the following problems: anisometropia, anisocoria, astigmatism, myopia, hyperopia, gaze misalignment, or a combination. RESULTS: Overall, eye exam referral rates have increased since 2012 (11.9% in 2012, 19.7% in 2023), with a disproportionate increase in referrals from Title 1 schools (25.2% in 2023) vs. Non-Title 1 schools (11.9% in 2023) (p < 0.001). This is largely due to a significantly higher prevalence of astigmatism referrals in Title 1 students (20.9%) compared to Non-Title 1 students (7.5%). Although a higher percentage of Title 1 students are reported to have eye correction (24.4% vs 16.6%), only a slightly higher percentage of Title 1 students wore eye correction during screening (11.5% vs 10.5%). CONCLUSION: Students at Title 1 schools may have a higher rate of amblyopia risk factors. Additional eye care-based interventions should be taken to reduce the risk of amblyopia in this population.

Tolerance to induced astigmatism of patients with trifocal or extended depth of focus intraocular lens implantation.

Background: Residual astigmatism is common after cataract surgery involving implantation of an intraocular lens, yet the tolerance of presbyopia-correcting intraocular lens to astigmatism of different magnitudes and axes is poorly understood. Here we compared visual acuity and quality in the presence of induced astigmatism after implantation of a trifocal or extended-depth-of-focus (EDOF) intraocular lens, the two widely used presbyopia-correcting intraocular lenses. Methods: At least 3 months after implantation of a TFNT00 or ZXR00 intraocular lens, patients were analyzed by slit-lamp examination, non-contact tonometry, subjective refraction, iTrace aberrometry, and corneal topography. After correction of residual astigmatism, astigmatism of different magnitudes on different axes was induced using cylindrical lenses, and overall visual acuity was measured, while objective visual quality was measured using the Optical Quality Analysis System II. Subjects were also asked about subjective visual quality using the Visual Function-14 questionnaire. Results: Comparison of 18 individuals who received a trifocal lens and 19 who received an EDOF lens showed that objective visual quality was better in the EDOF group regardless of the magnitude or axis of the induced astigmatism. In both groups, astigmatism of at least -1.00 DC influenced distant vision more severely when the axis was 45° than 0° or 90°, meanwhile astigmatism of at least -1.50 DC influenced near and intermediate vision more severely when the axis was 45° than 0° or 90°. Conclusion: Trifocal or EDOF intraocular lenses are less tolerant of oblique astigmatism than astigmatism with or against the rule. EDOF lenses may provide better objective visual quality than trifocal lenses in the presence of astigmatism, regardless of its magnitude or axis.

[On the issue of diagnostic accuracy of methods for analyzing the parameters of regular astigmatism]. / K voprosu o diagnosticheskoi tochnosti metodov indikatsii pokazatelei regulyarnogo astigmatizma.

Accurate measurement of astigmatism parameters is the basis for prescribing modern means of optical correction. In recent years, another direction for correcting astigmatism has emerged - implantation of toric intraocular lenses (TIOL). PURPOSE: This study evaluates the diagnostic accuracy of various methods for measuring the parameters of regular astigmatism. MATERIAL AND METHODS: The study included 83 patients (122 eyes) with regular astigmatism exceeding 1.0 D. Three groups were formed depending on the type of astigmatism. Spherical and cylindrical (power and axis) components of refraction were determined using automatic refractometry. The results were refined with subjective tests: power and axis tests with a cross-cylinder. The criterion for diagnostic accuracy was the level of corrected visual acuity. To assess the impact of cylinder position on visual acuity, discrete deviations of the axis of trial astigmatic lenses from the correct position (determined based on subjective tests) were modeled at 5, 10, and 15 degrees in both clockwise and counterclockwise directions. RESULTS: In the overall sample of observations, coincidence of results was found only in one-third of cases, with a tendency for discrepancies in data between the two methods in nearly 70% of cases. Statistical processing revealed significant differences only in the magnitude of the cylinder in the group with against-the-rule astigmatism (p<0.0005). An increase in maximum visual acuity corrected based on subjective test data was noted. With a deviation of the cylinder axis from the correct position by 10-15 degrees, regardless of the type of astigmatism, a significant tendency for a decrease in visual acuity was identified. At the same time, with a deviation of the cylinder axis within 5 degrees, a significant decrease in visual acuity was noted only in with-the-rule astigmatism and counterclockwise deviation. CONCLUSION: To achieve maximum visual acuity in the correction of regular astigmatism, objective method data must be refined with subjective tests. The results of modeling the deviation of the axis of the corrective lens from the proper position can be considered when evaluating the functional outcomes of TIOL implantation.

[Options for contact correction after keratoplasty]. / Vozmozhnosti kontaktnoi korrektsii posle keratoplastiki.

Keratoplasty is a radical surgical method for treating various corneal pathologies. Today, there are many types of keratoplasty, each aiming to restore the integrity and transparency of the cornea. However, keratoplasty-induced ametropia often prevents achieving high visual acuity and makes impossible the use of conventional optical correction methods such as glasses or soft and traditional rigid contact lenses. In this regard, the use of scleral contact lenses is the most optimal method for optical correction of postoperative refractive anomalies, ensuring successful visual rehabilitation and preventing the need for additional keratorefractive interventions.

A short-term comparison of surgical results between an ab-externo microshunt and trabeculectomy with a main focus on postoperative corneal astigmatism.

PURPOSE: To compare surgical results between ab-externo microshunt surgery and trabeculectomy, focusing on postoperative corneal astigmatism. STUDY DESIGN: Retrospective study. METHODS: Subjects were patients with glaucoma who underwent either standalone ab-externo microshunt surgery or trabeculectomy. Data on ophthalmic examinations obtained preoperatively and 1, 3, and 5 months postoperatively were analyzed. To assess corneal astigmatism, two separate data sets measured by anterior segment optical coherence tomography and autorefractometer were evaluated. Multivariate linear mixed model analyses were conducted to identify factors associated with the astigmatism changes. RESULTS: Sixty eyes were examined: 13 eyes underwent microshunt surgery, and 47 eyes underwent trabeculectomy. The total corneal astigmatism measurements by anterior segment optical coherence tomography (AS-OCT) were: - 1.15 ± 0.85 D and - 1.17 ± 0.81 D for the microshunt and trabeculectomy groups, respectively, preoperatively. At five months postoperatively they were - 0.92 ± 0.47 D and - 1.61 ± 0.83 D, respectively (P = 0.807 for the microshunt group and P = 0.005 for the trabeculectomy group: Wilcoxon signed-rank test). AS-OCT also indicated similar results for posterior corneal astigmatism. Autorefractometry also found the total corneal astigmatism was significantly changed only in the trabeculectomy group. The linear mixed model analysis revealed that trabeculectomy (P = 0.001), older age (P = 0.004), and longer postoperative period (P = 0.015) were correlated with greater astigmatism changes. The intraocular pressures significantly decreased following both surgical treatments. CONCLUSIONS: Standalone ab-externo microshunt surgery has less effect on corneal astigmatism during a 5 month period than trabeculectomy. Both surgical procedures significantly reduced intraocular pressure.

How does the Surgical Repair of Ptosis Impact Refractive Error?

PURPOSE: To identify a correlation between the degree of congenital ptosis and levels of refractive error, visual stimulus deprivation and anisometropic amblyopia, and any improvement with surgical intervention. METHODS: A prospective investigation of 30 patients aged 3 months to 8 years, with a diagnosis of unilateral or bilateral congenital ptosis. A full orthoptic assessment and cycloplegic refraction were performed and patients requiring surgical intervention for ptosis were at surgeon discretion. RESULTS: The mean age at presentation was 27.1 months. The prevalence of amblyopia ranged from 19 to 29%. There was no significant difference in the levels of astigmatism throughout the follow-up period between patients who underwent surgical intervention and who did not. There was a significant improvement in the visual acuity of the affected eye (p = .03) and both eyes open (p = .02), in patients who did not undergo surgery. This was then repeated on patients who underwent surgical intervention which showed no significant difference in the affected eye or both eyes open; p = .27, p = .32, respectively. CONCLUSION: There is no significant change in the levels of astigmatism in both patients who underwent surgery and those who did not. Conservative management of congenital ptosis, while counterintuitive, proves not to deleteriously affect the visual potential of these patients.

Characteristics of astigmatism in school-age children aged 5 to 13 years in northeast Sichuan: a cross-sectional school-based study.

Background: Astigmatism is closely associated with myopia progression, vision loss, eye fatigue and amblyopia, which seriously endangers children's eye health. This study aims to investigate the prevalence and characteristic distribution of astigmatism in children in Langzhong City, providing valuable insights for allocating resources and develop prevention and control strategies. Methods: A cross-sectional study and random sampling survey were conducted. Between January and November 2021, 21,415 students aged 5 to 13 years from 14 primary schools in Langzhong City underwent non-cycloplegic refractive testing using autorefraction. The data on myopia were analyzed using SPSS (Statistical Package for the Social Sciences) version 23.0. Results: The inclusion criterion was set at an absolute astigmatism value of ≥0.50D. Among the 21,415 children studied, 61.70% were found to have astigmatism. The prevalence of astigmatism varied significantly across different grades (χ2=501.414, P<0.001). The predominant types of astigmatism were mild astigmatism (0.50-1.00D) and with-the-rule astigmatism. Mixed astigmatism was primarily observed in children in grades 1 and 2, while compound myopic astigmatism was more common in children in grades 3 to 6. These differences were statistically significant. As the degree of astigmatism increased, the proportions of against-the-rule astigmatism, oblique astigmatism, compound myopic astigmatism, and simple hyperopic astigmatism decreased, whereas the proportions of with-the-rule astigmatism, mixed astigmatism, and compound hyperopic astigmatism increased. Conclusions: The prevalence of astigmatism among school-age children aged 5 to 13 years in northeast Sichuan is notably high, with compound myopic astigmatism and with-the-rule astigmatism being the most common types. Regular refractive examinations are crucial for the early detection and management of astigmatism.