Keratoconus (KC) is a corneal thinning dystrophy that leads to visual impairment. While the cause of KC remains poorly understood, changes in sex hormone levels have been correlated with KC development. This study investigated circulating gonadotropin-releasing hormone (GnRH) in control and KC subjects to determine if this master hormone regulator is linked to the KC pathology. Plasma and saliva were collected from KC subjects (n = 227 and n = 274, respectively) and non-KC controls (n = 58 and n = 101, respectively), in concert with patient demographics and clinical features. GnRH levels in both plasma and saliva were significantly lower in KC subjects compared to controls. This finding was retained in plasma when subjects were stratified based on age, sex, and KC severity. Control and KC corneal fibroblasts (HKCs) stimulated with recombinant GnRH protein in vitro revealed significantly increased luteinizing hormone receptor by HKCs and reduced expression of α-smooth muscle actin with treatment suggesting that GnRH may modulate hormonal and fibrotic responses in the KC corneal stroma. Further studies are needed to reveal the role of the hypothalamic–pituitary–gonadal axis in the onset and progression of KC and to explore this pathway as a novel therapeutic target.

To evaluate the predictive performance of traditional intraocular lens (IOL) power calculation formulas (e.g., SRK/T, Haigis, Hoffer Q, and Holladay I) compared to advanced regression models, including classical linear models, regression splines, and random forest regression, in predicting postoperative refraction following cataract surgery. Retrospective, comparative analysis of IOL power calculations. The study included 886 eyes from 631 patients who underwent cataract surgery with monofocal aspherical IOL implantation. Biometric measurements were obtained using optical biometry (IOLMaster 700), and postoperative refraction was assessed at least four weeks after surgery. Formula constants for five IOL formulas (SRK/T, Haigis, Hoffer Q, Holladay I and Castrop V1) were optimized using root mean squared error (RMSE). Regression models (classical linear model, regression splines, and random forest regression) were trained on four datasets categorized by axial length (AL); normal, short, long, and random. Model performance was assessed using mean absolute error (MAE), RMSE, and prediction error variance, for both in-sample and out-of-sample predictions. The primary parameters measured were MAE, RMSE, and prediction error variance. Regression models outperformed traditional IOL formulas in in-sample prediction error. Overall, linear regression models performed similarly to traditional formulas with respect to out-of-sample prediction error. The lowest out-of-sample prediction error (MAE = 0.279, RMSE = 0.359) was achieved with a model where effects of some covariates (R2, AL, CCT) were modelled as nonlinear via regression splines. This model outperformed all traditional formulas, and the Castrop formula, which had the lowest errors among the formulas (MAE = 0.284, RMSE = 0.359). Random forest regression showed strong in-sample performance but poor out-of-sample generalizability due to overfitting. Regression models which allow for nonlinear effects, e.g. based on regression splines, provide a promising alternative to traditional IOL formulas for predicting postoperative refraction. Linear regression and random forest regression models can reduce in-sample error, however, their clinical utility is currently limited by out-of-sample performance. Future work should focus on improving generalizability and integrating machine learning models into clinical practice to enhance refractive outcomes, especially for eyes with atypical anatomy.

Purpose: To investigate the luminance capacity and achievable threshold levels of commercially employed virtual reality (VR) devices for visual field testing. Methods: This two-part study included (1) a literature review of VR headsets used for perimetry with luminance data extracted from technical specifications in publications and manufacturers; and (2) empirical evaluation of three most employed VR headsets in the literature using a custom virtual testing environment. Results: Three most employed VR devices for visual field testing were Pico Neo, Oculus Quest, and HTC Vive. The maximum reported luminance was 250 cd/m² for the HTC Vive Pro. Information on luminance measurement was not consistently available, reporting only handheld luminance meters. Empirical measurements show that handheld luminance meters significantly overestimate luminance compared to standard spectroradiometers. Measured luminance varies significantly across aperture size and decreases for peripheral stimuli up to 30 degrees peripherally. Assuming conventional background of 10 cd/m², the best performance with lowest possible thresholding was with HTC Vive at 16dB, corresponding to luminance of 80 cd/m² centrally. Oculus Quest 2 and Pico Neo 3 had minimum threshold of 20dB. Conclusion: Commercially available VR devices do not meet luminance requirements or threshold sensitivities for visual field testing. Current VR technology is not designed—nor has the capacity—to threshold at mid-to-low dB ranges, which limits accuracy in diagnosing and monitoring defects seen in glaucoma. Translational Relevance: This study highlights the technical limitations of current commercially available VR devices for visual field testing and significant variables in evaluating luminance performance in these devices.

Purpose: To compare refractive, visual, and safety outcomes of 3 methods for surgical correction of aphakia: anterior chamber intraocular lens (AC IOL), intrascleral haptic fixation intraocular lens (ISHF-IOL), and Gore-Tex suture fixation of modified eyelet toric intraocular lens (GSF-MET IOL). Setting: Tertiary care academic center. Design: Multisurgeon retrospective case series. Methods: Review of 357 eyes undergoing one of the above 3 techniques between 2017 and 2024. Comparative refractive (defocus [spherical equivalent (SE)], astigmatism [refractive cylinder (RefCyl)], and blur [defocus equivalent]), visual acuity (corrected distance visual acuity [CDVA]), and safety outcomes (cystoid macular edema and return to the operating room [ROR] events) were recorded. Owing to concerns about IOL tilting with one of the models, a subgroup analysis was performed on 2 IOL models within the ISHF group. Statistical analyses included descriptive statistics, chi-square tests, 1-way analysis of variance, and 2-sample t testing. Results: All 3 groups had similar SE ( P = .87), RefCyl ( P = .91), and CDVA in eyes without significant comorbidities ( P = .23). ROR was similar among all groups ( P = .08). Within the ISHF-IOL group, CT Lucia 602 and Sensar AR40 had similar SE and RefCyl ( P = .18 and P = .15, respectively). CDVA was similar in eyes without significant comorbidities for both IOL models ( P = .70). ROR was significantly higher with CT Lucia 602 than with Sensar AR40 ( P = .03). Conclusions: All 3 surgical techniques can provide good refractive, visual acuity, and safety outcomes. Within the ISHF-IOL group, the Sensar AR40 had lower ROR rates than the CT Lucia 602, with similar CDVA outcomes.

Purpose: To evaluate whether primary graft failure (PGF) rates and endothelial cell loss (ECL) differ between surgeon-trephined/loaded and eye bank-preloaded Descemet-stripping automated endothelial keratoplasty (DSAEK) grafts. Setting: Tertiary care academic center. Design: Retrospective case series and ex vivo laboratory study. Methods: Single-center review of 69 eyes undergoing DSAEK (2020-2023) divided into 3 groups based on graft preparation and eye bank source: (1) eye bank-preloaded in EndoSerter (PL-ES), (2) eye bank-preloaded in glass tube (PL-GT), and (3) surgeon-trephined/loaded in EndoSerter (SL-ES). The primary clinical outcome was PGF (persistent corneal edema >3 months despite medical therapy). Secondary outcomes included visual outcomes and clinical complications (cystoid macular edema [CME] and rebubbling rate [RR]). The primary outcome of the laboratory study was percentage ECL (%ECL). Results: All lenticules were ≤80 μm. PGF was significantly higher in the PL-ES group (8/20; 40%) and the PL-GT group (4/7; 57%) compared with the SL-ES group (1/42; 2%) ( P < .0001). Grafts requiring rebubbling were more likely to experience PGF ( P = .0176). PGF eyes were regrafted with SL-ES DSAEK; none experienced subsequent PGF. There were no significant differences in CME, RR, corrected distance visual acuity, and spherical equivalent. The ex vivo study included 9 PL-ES, 6 PL-GT, and 6 SL-ES grafts. %ECL was higher in both preloaded groups than SL-ES ( P = .0354), although significance was not demonstrated on post hoc analysis. Fluorescent imaging revealed more cell loss in preloaded grafts. Conclusions: Preloading and storage of DSAEK grafts may affect PGF rates clinically and ECL ex vivo.

This case report discusses a unique presentation of an artery of Percheron (AOP) infarct resulting in rapidly resolving internuclear ophthalmoplegia (INO) without classical signs. This is the case of a 70-year-old male patient who presented to a community Emergency Department following acute code stroke activation. Physical exam and imaging studies including non-contrast CT, CT angiography, CT perfusion, and MRI were performed. A review of the literature was also conducted. MRI confirmed acute bilateral thalamic ischemic changes consistent with AOP infarcts. Symptoms of acute blurred vision, slurred speech, right hemi-face and tongue numbness, and signs of anisocoria, left INO, mild left skew deviation, and impaired convergence on the left resolved within 48 hours without intervention. The patient was discharged as neurologically normal and follow-up investigations did not identify a cause for the stroke. The literature suggests varying presentations of AOP infarcts, with INO being rare. This case deviates from classical AOP presentations, emphasizing the importance of considering AOP infarcts early in differential diagnoses, particularly with unusual neuro-ophthalmological findings. Imaging modalities such as MRI with DWI prove crucial for early diagnosis, although AOP occlusions remain challenging to detect due to the small vessel size. Our case contributes to expanding knowledge of AOP infarct presentations and underscores the need for vigilance in recognizing atypical manifestations for timely diagnosis/management.