Medical hypothesis, discovery & innovation in optometry

Background: Patients undergoing corneal transplantation often present with high astigmatism and corneal irregularity, making conventional contact lens fitting difficult and limiting tolerance to standard optical correction. We aimed to evaluate the effect of scleral lens fitting on visual rehabilitation in patients following lamellar or penetrating keratoplasty by assessing visual acuity, contrast sensitivity, and patient satisfaction.
Methods: Patients who had undergone keratoplasty and were considered suitable candidates for scleral lens fitting were enrolled in this prospective interventional study. All participants underwent comprehensive ophthalmic and optometric examinations prior to lens fitting. Visual acuity and contrast sensitivity were measured using a standard Snellen visual acuity chart and the Melbourne Edge Test under standardized back-illuminated conditions, with results recorded in decimal notation and decibels (dB), respectively. Refractive error was assessed by autorefractometry, followed by over-refraction and subjective and objective refinement to determine the final lens power. Diagnostic fitting was performed using trial scleral lenses, and anterior segment optical coherence tomography was utilized to assess lens fit. Visual and refractive parameters were recorded before and after optimal scleral lens fitting. Patient-reported satisfaction was assessed 1–2 weeks after lens dispensing using a 0–10 subjective rating scale, where scores 8–10 indicated complete satisfaction, 5–7 satisfaction, 2–4 dissatisfaction, and 0–1 complete dissatisfaction.
Results: Eighteen eyes of 12 post-keratoplasty patients, 7 (58%) men and 5 (42%) women, were evaluated. Mean (standard deviation [SD], range) age was 45.6 (3.9, 22–67) years. Mean (SD) visual acuity improved significantly from 0.15 (0.12) decimal before lens fitting to 0.77 (0.33) decimal after scleral lens wear (P < 0.001). Mean contrast sensitivity increased significantly from 14.55 (3.82) dB to 20.33 (2.35) dB following scleral lens fitting (P < 0.001). All patients reported satisfaction with scleral lens wear, including complete satisfaction in nine (75%) patients and satisfaction in three (25%) patients.
Conclusions: Post-keratoplasty ametropia and irregular astigmatism frequently limit visual rehabilitation with conventional optical correction methods. Scleral lenses offer an effective approach for correcting postoperative refractive irregularities and significantly enhance visual acuity and contrast sensitivity, while yielding high patient satisfaction at two weeks after lens fitting.

Background: With the rapid growth of the aging population in Nepal, the number of older adults residing in old age homes has increased substantially. Elderly individuals living in institutional settings are at higher risk of visual impairment (VI) and blindness compared to their community-dwelling counterparts, largely due to limited access to eye care services and underutilization of available interventions. This study aimed to assess the prevalence of ocular morbidity and to identify the major causes of VI and blindness among elderly residents of old age homes in East Nepal.
Methods: A community-based cross-sectional study was conducted among individuals aged ≥ 60 years living in six old age homes in Koshi Province, Nepal. Distance visual acuity was assessed using an E-optotype Snellen chart at 6 meters, near visual acuity was evaluated using a reduced Snellen chart at 33 cm under standard illumination. Objective refraction was performed using a streak retinoscope, and both uncorrected and best-corrected distance visual acuity (UCDVA and BCDVA) were recorded for the better-seeing eye. Comprehensive ocular examination, including anterior and posterior segment evaluation, was performed using standard clinical techniques. In cases with multiple ocular conditions, the primary cause of VI was determined based on the condition contributing most to vision loss.
Results: A total of 236 elderly residents were enrolled, with a mean (standard deviation) age of 70.5 (9.5) years (range: 60–102). Nearly half of the participants (n = 116, 49.2%) were aged 60–69 years, the majority female (n = 146, 61.9%). Ocular morbidity was detected in 94.7% (n = 447) of eyes. The prevalence of VI and blindness based on presenting visual acuity was 57.4%; this decreased to 39.4% following refractive correction, indicating an 18% absolute reduction. Cataracts (n = 229 eyes, 48.5%) were the leading cause of VI and blindness, followed by refractive error, corneal opacity, retinopathy, and glaucoma. A statistically significant association was observed between age and VI/blindness (P < 0.05), whereas no significant association was found with sex (P > 0.05).
Conclusions: VI and blindness are highly prevalent among elderly residents in old age homes, with a substantial proportion attributable to avoidable causes. Timely refractive correction, regular comprehensive eye examinations, and increased uptake of cataract surgery could significantly reduce the burden of VI and improve quality of life in this vulnerable population. Strengthening outreach eye care services and integrating routine vision screening into residential care systems are essential to address this largely preventable public health challenge.

Background: Binocular vision dysfunction is frequently overlooked in polytrauma care despite its established impact on reading, driving, and return to work. We aimed to determine the prevalence and patterns of binocular vision dysfunction in polytrauma patients with ocular involvement and to identify independent clinical predictors.
Methods: We conducted a retrospective cohort study of adults (≥ 18 years) admitted to Sina Hospital Trauma Center, Tehran between January 2021 and December 2023 with an Injury Severity Score (ISS) ≥ 16 and ophthalmology-confirmed ocular involvement. Four binocular parameters—near point of convergence, stereoacuity, fusional vergence amplitudes, and accommodative facility—were extracted from consultation records when available. Prevalence estimates were calculated using the Wilson score method, and multivariable logistic regression identified independent predictors.
Results: Among 2923 polytrauma admissions, 438 patients (15.0%) had ocular involvement; 312 (71.2%) had complete binocular data (mean [standard deviation] age 37.8 [14.2] years; 84.6% [n = 264] male). At least one binocular dysfunction was identified in 134 patients (42.9%; 95% confidence interval [CI], 37.4–48.6). Convergence insufficiency was most common (n = 119, 38.1%; 95% CI, 32.8–43.7), followed by reduced stereopsis (n = 87, 27.9%; 95% CI, 23.1–33.2), accommodative dysfunction (n = 67, 21.5%; 95% CI, 17.2–26.4), and reduced fusional vergence amplitude (n = 54, 17.3%; 95% CI, 13.4–22.0). Only 24.7% (n = 77) of patients received formal optometric referral during acute admission. Independent predictors were blunt orbital trauma (adjusted odds ratio [aOR] 2.81, 95% CI, 1.67–4.73), concomitant traumatic brain injury (aOR 2.14, 95% CI, 1.29–3.55), and age 18–35 years (aOR 1.92, 95% CI, 1.12–3.28) (all P < 0.05).
Conclusions: Binocular vision dysfunction affects nearly half of polytrauma patients with ocular involvement yet is substantially under-recognized and under-referred. Incorporating a brief binocular screening into routine post-trauma ophthalmologic assessment may represent a low-cost strategy to mitigate long-term visual and functional disability. Future prospective, multicenter studies employing standardized optometric assessment protocols and longitudinal follow-up are warranted to better define the natural history of these observed binocular dysfunctions and to evaluate the impact of early detection and targeted intervention on functional outcomes.

Background: University students are increasingly exposed to prolonged digital device use for academic activities, which places them at risk of digital eye strain (DES). While prevalence is widely reported, limited attention has been given to students’ awareness and preventive practices. This study aimed to determine the prevalence of DES, associated behavioral patterns, and preventive practices among university students.
Methods: A descriptive cross-sectional study was conducted during the Spring semester of the 2025–2026 academic year at the University of Buraimi, Oman. Using stratified random sampling, 240 undergraduate students were recruited from all four colleges. Data were collected through an online survey comprising demographic characteristics, digital device usage habits, the validated Computer Vision Syndrome Questionnaire (CVS-Q), and items assessing awareness and preventive practices.
Results: Overall, 58.8% (n = 141) of participants were classified as having DES, with the majority experiencing mild symptoms (n = 89, 37.1%), followed by moderate (n = 40, 16.7%) and severe (n = 12, 5.0%) symptoms. The most commonly reported symptoms were tearing (n = 137, 57.1%), ocular dryness (n = 125, 52.1%), eye redness (n = 115, 47.9%), burning sensation (n = 104, 43.3%), and itching (n = 104, 43.3%). Prolonged screen exposure was common, with 72.5% (n = 174) reporting ≥ 5 h of daily use, alongside frequent use of multiple devices and suboptimal ergonomic practices, including close viewing distances and poor posture. Awareness of DES was reported by 37% (n = 87) of participants, yet adoption of preventive practices was inconsistent. A statistically significant association was observed between engagement in preventive practices and lower DES severity (P < 0.05), whereas awareness alone was not significantly associated with symptom severity (P > 0.05).
Conclusions: The findings of this study indicate a 58.8% prevalence of DES among Omani university students. Prolonged screen time emerged as a key predictive factor. Awareness of DES was limited, and adherence to preventive practices remained low. These results underscore the need for targeted educational interventions on eye health, emphasizing simple and effective strategies such as the 20‑20‑20 rule to reduce the burden of DES among university students.

Background: Accurate keratometric assessment is essential for precise intraocular lens (IOL) power calculation in cataract surgery. Artificial tears are commonly used to optimize the ocular surface, yet their short-term effects on keratometric and biometric measurements remain uncertain. This study evaluated the impact of artificial tears with different viscosities on keratometry and optical biometry parameters in cataract patients with and without dry eye disease (DED).
Methods: This prospective, randomized cross-over study included 40 cataract patients (20 with DED and 20 with normal ocular surfaces). Each participant received high- and low-viscosity artificial tears on separate visits. Keratometric parameters (K1, K2), axial length (AL), anterior chamber depth (ACD), and calculated IOL power were measured using optical biometry at baseline and at 30 s, 2 min, and 5 min after drop instillation.
Results: Participants with DED were significantly older than those with normal ocular surfaces (P < 0.05), while sex distribution and intraocular pressure were comparable between groups (both P > 0.05). Both formulations induced significant transient changes in keratometric measurements, most evident at 30 s and 2 min post-instillation, with stabilization by 5 min (within-group P < 0.05). These fluctuations were more pronounced in eyes with DED, particularly with high-viscosity drops, which showed large within-subject effect sizes. No significant differences in K1 or K2 were observed between groups at post-instillation timepoints (all P > 0.05). AL and ACD remained stable across all groups and timepoints (all P > 0.05). A modest but statistically significant reduction in calculated IOL power was observed only in DED eyes receiving high-viscosity artificial tears (P < 0.05).
Conclusions: Artificial tears induce transient alterations in keratometric measurements, particularly within the first 2 min after instillation and in eyes with tear film instability. High-viscosity formulations exert more pronounced effects and may influence IOL power calculations. To ensure accurate optical biometry, keratometry should be deferred for at least 5 min following artificial tear instillation, especially in patients with DED.

Background: The 12-item Ocular Surface Disease Index (OSDI) is widely used to assess dry eye disease (DED) severity; however, its length may reduce patient compliance and clinical efficiency. Given the expanding role of machine learning in ophthalmology, we aimed to develop and validate a compact OSDI predictor using supervised machine learning techniques to improve the efficiency and accuracy of DED assessment.
Methods: This retrospective study analyzed a dataset of complete 12-item OSDI questionnaires obtained from adult residents of the Gaza Strip. OSDI scores were recalculated using the standard scoring formula, with “not applicable” responses treated as missing and excluded from the denominator. Participants were categorized as having moderate-to-severe dry eye (OSDI > 22) or not. Three supervised machine learning models—decision tree, support vector machine, and logistic regression—were developed using Python. Binary feature-importance analysis was initially performed using the full 12-item OSDI, after which each model was retrained using only questionnaire items with a binary feature-importance value of 1. Model performance was evaluated using accuracy, sensitivity, specificity, and precision.
Results: Among 452 participants (mean [standard deviation] age, 32.0 [11.8] years; 52.9% male), 252 (55.8%) were classified as having moderate-to-severe dry eye, 200 (44.2%) were not. In the reduced-feature testing models, support vector machine model demonstrated the best overall performance, achieving 94.5% accuracy, 98.0% sensitivity, 90.0% specificity, and 92.6% precision. Logistic regression also showed strong performance, with 93.4% accuracy, 98.0% sensitivity, 87.5% specificity, and 90.9% precision. The decision tree model yielded lower testing accuracy (78.0%) and sensitivity (70.6%) but maintained relatively high specificity (87.5%) and precision (87.8%). Feature-importance analysis identified sensitivity to light, gritty sensation, computer or bank machine use, windy conditions, low-humidity environments, and air-conditioned places as informative predictors in the decision tree model. Both support vector machine and logistic regression models identified gritty sensation, painful or sore eyes, blurred vision, reading, watching television, and air-conditioned places as key predictors.
Conclusions: Supervised machine learning models, particularly support vector machine and logistic regression models, effectively classified moderate-to-severe dry eye using recalculated standard OSDI scores and reduced feature sets. The identified predictors underscore the importance of ocular discomfort, visual disturbance, sustained visual activities, and environmental triggers in DED symptom severity. These findings support the potential utility of machine learning-assisted tools for symptom-based DED screening and severity assessment. Further validation in independent clinical populations and integration with objective diagnostic measures are warranted.