Medical Hypothesis, Discovery & Innovation (MEHDI) Ophthalmology Journal
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Artificial intelligence in ophthalmology: opportunities, challenges, and ethical considerations
Full text linkBackground: By leveraging the imaging-rich nature of ophthalmology and optometry, artificial intelligence (AI) is rapidly transforming the vision sciences and addressing the global burden of ocular diseases. The ability of AI to analyze complex imaging and clinical data allows unprecedented improvements in diagnosis, management, and patient outcomes. In this narrative review, we explore the current and emerging opportunities of utilizing AI in the vision sciences, critically examine the associated challenges, and discuss the ethical implications of integrating AI into clinical practice.
Methods: We searched PubMed/MEDLINE and Google Scholar for English-language articles published from January 1, 2005, to March 31, 2025. Studies on AI applications in ophthalmology and optometry, focusing on diagnostic performance, clinical integration, and ethical considerations, were included, irrespective of study design (clinical trials, observational studies, validation studies, systematic reviews, and meta-analyses). Articles not related to the use of AI in vision care were excluded.
Results: AI has achieved high diagnostic accuracy across different ocular domains. In terms of the cornea and anterior segment, AI models have detected keratoconus with sensitivity and accuracy exceeding 98% and 99.6%, respectively, including in subclinical cases, by analyzing Scheimpflug tomography and corneal biomechanics. For cataract surgery, machine learning-based intraocular lens power calculation formulas, such as the Kane and ZEISS AI formulas, reduce refractive errors, achieving mean absolute errors below 0.30 diopters and performing particularly well in highly myopic eyes. AI-based retinal screening systems, such as the EyeArt and IDx-DR, can autonomously detect diabetic retinopathy with sensitivities above 95%, while deep learning models can predict age-related macular degeneration progression with an area under the receiver operating characteristic curve exceeding 0.90. In glaucoma detection, fundus and optical coherence tomography-based AI models have reached pooled sensitivity and specificity exceeding 90%, although performance varies with disease stage and population diversity. AI has also advanced strabismus detection, amblyopia risk prediction, and myopia progression forecasting by using facial analysis and biometric data. Currently, key challenges in implementing AI in ophthalmology include dataset bias, limited external validation, regulatory hurdles, and ethical issues, such as transparency and equitable access.
Conclusions: AI is rapidly transforming vision sciences by improving diagnostic accuracy, streamlining clinical workflow, and broadening access to quality eye care, particularly in underserved regions. Its integration into ophthalmology and optometry thus holds significant promise for enhancing patient outcomes and optimizing healthcare delivery. However, to harness the transformative potential of AI fully, sustained multidisciplinary collaboration, involving clinicians, data scientists, ethicists, and policymakers, is essential. Rigorous validation processes, transparency in algorithm development, and strong ethical oversight are equally important to mitigate risks such as bias, data misuse, and unequal access. Responsible implementation of AI in the vision sciences is essential to ensure that all populations are served equitably
Visio-spatial intelligence skills in non-athletes versus amateur boxers
Full text linkBackground: Visio-spatial intelligence (VSI) skills, including abilities such as spatial awareness, visual processing, and motor coordination, are crucial for athletic performance, particularly in combat sports such as boxing. Amateur boxers require efficient visio-spatial skills (VSS) to quickly process visual information, track opponents’ movements, and execute precise techniques. However, the extent to which amateur boxing experience enhances VSS remains unclear. This study compared the VSI skills of amateur boxers to those of non-athletes.
Methods: This cross-sectional, observational study recruited amateur boxers and non-athletes in the King Cetshwayo District, KwaZulu-Natal, Republic of South Africa. Participants, aged 18 to 27 years, underwent a detailed optometric screening and VSS tests, including accommodation facility, saccadic eye movements, speed of recognition, hand-eye coordination, peripheral awareness, and visual memory.
Results: The study included 90 participants, consisting of 45 amateur boxers (28 [62%] men aged 18 to 25 years and 17 [38%] women aged 18 to 27 years) and 45 non-athletes (29 [64%] men aged 18 to 26 years and 16 [36%] women aged 18 to 27 years). The mean (standard deviation) age of the boxers was 20.7 (2.2) years, whereas the mean age of the non-athletes was 21.9 (2.4) years (P < 0.05). Amateur boxers were superior in VSS, with marked advantages in accommodation facility, saccadic eye movement, speed of recognition, peripheral awareness, and hand-eye coordination (all P < 0.001). However, no significant difference was found in visual memory (P > 0.05). The greatest difference was observed in speed of recognition (88% higher in boxers), and the least difference was observed in visual memory (4% higher in boxers).
Conclusions: VSS differ between amateur boxers and non-athletes, indicating the importance of these skills for athletic performance. These findings emphasize the potential advantages of boxing training in enhancing VSS, which could impact athletic training and performance-enhancement strategies. This underscores the value of integrating visio-spatial training into athletic programs. The observed superiority of boxers in specific VSS areas has broad implications for theories of sports vision, the selection of appropriate tests, and the development of sport-specific VSS testing protocols. Further longitudinal studies with larger sample sizes are required to verify these findings and assess changes in these skills over time
Relationship between central corneal thickness and optic nerve head parameters in primary open-angle glaucoma
Full text linkBackground: Primary open-angle glaucoma (POAG) is an ocular entity that causes optic neuropathy. Thin central corneal thickness (CCT) in patients with POAG correlates with changes in various optic nerve head structural parameters. Additionally, racial differences exist in CCT and optic disc parameters. Herein, we assessed the potential relationship between CCT and optic nerve head parameters in treatment-naive patients of Persian ethnicity who were diagnosed with POAG of varying severity levels.
Methods: This hospital-based analytical cross-sectional study recruited patients of Persian ethnicity diagnosed with treatment-naive POAG. Participants underwent detailed optometric and ophthalmic examinations. Visual field testing was performed using a Humphrey perimeter. Spectral-domain optical coherence tomography (OCT) was performed using a Cirrus OCT device to record optic nerve head parameters: disc area, rim area, vertical cup-to-disc ratio, average cup-to-disc ratio, cup volume, and average retinal nerve fiber layer thickness (RNFLT). The CCT was measured using an ultrasonic pachymeter.
Results: We recruited 168 eyes of 84 patients with POAG with a mean (standard deviation) age of 60.30 (12.50) years, comprising 33 (39.29%) men and 51 (60.71%) women. While weak but statistically significant inverse correlations of CCT with the vertical cup-to-disc ratio (r = - 0.19; P < 0.05), average cup-to-disc ratio (r = - 0.17; P < 0.05), and cup volume (r = - 0.17; P < 0.05) were found, other optic nerve parameters showed no significant correlations with CCT (all P > 0.05). Stepwise multiple linear regression analysis indicated that, for each unit increase in the vertical cup-to-disc ratio, the CCT decreased by 54.98 µm (P < 0.05).
Conclusions: The CCT in eyes with treatment-naive POAG of varying severity levels in a Persian ethnic group was weakly but statistically significantly inversely correlated with the vertical cup-to-disc ratio, average cup-to-disc ratio, and cup volume. For every unit increase in the vertical cup-to-disc ratio, the CCT decreased by 54.98 µm. Our findings indicate that in patients with POAG, CCT correlates with some changes in structural optic nerve head parameters, including the cup volume and vertical/average cup-to-disc ratios. Further longitudinal studies including individuals from various racial backgrounds and POAG severity levels are needed to verify the relationship between CCT and optic nerve parameters at different time points of disease progression
Visual impairment and blindness in diabetic retinopathy
Full text linkBackground: Diabetic retinopathy (DR) is a major microvascular complication of diabetes mellitus (DM) and a leading cause of preventable visual impairment (VI) and blindness worldwide. The rising global prevalence of DM, particularly in low- and middle-income regions such as the Middle East, necessitates the collection of localized data on DR-related VI. Despite growing public health concerns, limited research has been conducted in the Gulf region, including Oman. This study aimed to assess the prevalence and severity of VI associated with DR and identify its key risk factors among patients with types I and II DM in Al Buraimi, Sultanate of Oman.
Methods: A retrospective cross-sectional study was conducted at Buraimi Hospital and Polyclinic in Oman between June 2023 and January 2024. Medical records of patients with type I or II DM and a confirmed diagnosis of DR were reviewed. Best-corrected distance visual acuity was assessed using a Snellen chart, and fundus examinations were performed using both direct and indirect ophthalmoscopy for DR detection and staging. VI was classified according to the WHO criteria. Relevant demographic and clinical data, including age, duration of DM, and duration of DR, were extracted. Coexisting ocular conditions were also documented.
Results: A total of 218 participants were included, with a mean age of 57.5 years; 52.3% (n = 114) were male and 47.7% (n = 104) female. Most participants had no VI (n = 131, 60.1%), whereas mild VI (n = 58, 26.6%) was the most frequent type of VI. A significant association was detected between DR severity and VI levels (P < 0.01); blindness occurred only in patients with severe nonproliferative DR (n = 1) and proliferative DR (n = 8). Age and DR duration were significantly associated with increasing VI severity (both P < 0.05), with each additional year increasing the odds by 4% and 12%, respectively. No significant association was observed between DM duration and VI severity (P > 0.05). Cataract (n = 131) was the most common coexisting ocular condition.
Conclusions: The frequency of VI among patients with DR was relatively high, and its severity was significantly associated with older age and longer DR duration. Blindness occurred only in more severe DR stages, reinforcing the value of early screening and immediate care in mitigating disease severity. These findings indicate the need to optimize resources for early DR management and to promote screening, even in diabetic individuals with normal vision, to prevent disease progression and reduce visual disability. Further community-based research is needed to achieve a robust, practical understanding of the preventable causes of VI, guide national eye health policies, and enhance long-term patient outcomes
Clinical anatomy of the macula
Full text linkBackground: The macula is located at the center of the retina and is crucial for high-resolution color vision. Its complex anatomical structure supports a dense array of cone photoreceptors and specialized neuronal pathways essential for central vision. A thorough understanding of macular microanatomy is vital for accurate interpretation of retinal imaging and effective management of macular diseases. This narrative review provides a detailed and integrative overview of macular anatomy, emphasizing clinically relevant microanatomical features and their implications in retinal imaging and macular disease management.
Methods: A PubMed/MEDLINE search was performed using relevant keywords (e.g., “anatomy,” “fovea,” “foveal avascular zone,” “foveola,” “Henle fiber layer,” “macula,” “macular anatomy,” “macula lutea,” “optical coherence tomography,” “parafovea,” “perifovea,” and “retina”) to identify English-language articles published up to February 28, 2025. The reference lists of the included papers were manually reviewed to identify additional relevant sources. The review considered a wide range of study types, including clinical trials, systematic and narrative reviews, meta-analyses, observational studies, case series, and experimental animal studies.
Results: This review highlights the remarkable characteristics of the fovea and foveola, which are densely packed with cone photoreceptors, making them uniquely suited for sharp vision. The surrounding parafoveal and perifoveal regions offer critical structural and functional support, while the Henle fiber layer facilitates the oblique course of photoreceptor axons, further refining central vision. Moreover, high-resolution optical coherence tomography has revolutionized visualization of the macular architecture, enabling a detailed assessment of previously undetectable retinal layers. This review explores key anatomical features, such as the foveal avascular zone, precise photoreceptor organization, and the role of Muller glial cells, in the context of high-resolution imaging. These associations between anatomy and imaging enhance diagnostic precision and may inform targeted treatment approaches for macular diseases.
Conclusions: Comprehensive knowledge of macular anatomy is crucial for the accurate interpretation of retinal imaging and management of central retinal disorders. The bridging of classic histological findings with modern imaging enhances comprehension of the healthy macula and the detection and management of pathological changes. This review serves as a practical anatomical reference for clinicians and researchers in macular diagnostics and therapeutics. Further studies are warranted to explore how emerging imaging technologies can enhance early detection and treatment strategies for macular disorders
Scleral lenses and PROSE: indications, complications, and future challenges
Full text linkBackground: Scleral lenses (SLs) and prosthetic replacement of the ocular surface environment (PROSE) are the same device, designed to enhance the optical quality of irregular surfaces or ectatic corneas. They also improve the corneal surface epithelium and the ocular surface microenvironment for patients with severe ocular surface diseases, including dry eye. This review aims to provide a comprehensive overview of the indications for SL/PROSE, as well as an exhaustive analysis of the corresponding complications, their possible remedies, and future challenges in this rapidly evolving field of ophthalmology.
Methods: We conducted a review of the English language literature on the indications and complications of SL/PROSE devices using the following website search engines: National Library of Medicine’s PubMed, Google Scholar, EMBASE, Web of Science, and Scopus for articles in English published from inception up to July 2025. The following scientific reports were considered for analysis: systematic reviews and meta-analyses, randomized controlled trials, cohort studies, case-control series, case reports, editorials, and short communications.
Results: Research and development in SL/PROSE have made significant strides, broadening its applications, improving structural materials and designs, and adapting it to benefit a diverse range of patients facing numerous pathologies. These include keratoconus, post-refractive surgery ectasia, corneal transplantation, severe dry eye, and chronic cicatrizing ocular surface disorders, among many others. For patients suffering from these emerging pathologies, apart from medical therapy and surgical procedures there are limited treatment options. Currently, SL/PROSE offer a less invasive potential solution for many of these challenging conditions, raising hope and motivation within the field of corneal and ocular surface disease. However, they are not without potential complications, which differ significantly from those associated with soft contact lenses and rigid gas-permeable contact lenses. The most frequently reported SL/PROSE complications relate to improper lens adaptation and patients’ handling.
Conclusions: While much of the existing literature has focused on the benefits and applications of SL/PROSE devices, the potential complications associated with their use have received less attention and aren’t as widely explored
Ocular Surface Disease Index questionnaire in different languages
Full text linkBackground: The Ocular Surface Disease Index (OSDI) questionnaire was first introduced and developed in 1997 by the Outcomes Research Group, and was adopted by Allergan, Inc. (Irvine, Goleta, CA). While several tools are available for evaluating dry eye syndrome (DES), the OSDI questionnaire is known to have high reliability and validity. Additionally, although more complex questionnaires are available, the goal of the OSDI is to ensure a rapid diagnosis of ocular surface disease. The OSDI consists of a 12-item questionnaire designed to assess the visual disability caused by DES. The OSDI score can range from 0 to 100, with higher scores indicating greater disability. This language-inclusive mini-review aimed to provide an overview of previous studies that translated the OSDI into various languages and validated the translated versions.
Methods: OSDI validation studies were identified through a PubMed / MEDLINE and Google Scholar search spanning the 27 years since the establishment of the OSDI, using the broad term “Ocular Surface Disease Index-12 questions” and keywords that is “ocular surface disease index-12,” “translation and validation,” “transcultural validation,” “development,” “cross-cultural adaptation,” and “reliability and validity.” We included original studies that validated the translated version of the OSDI in various languages, presenting the key findings with a focus on reliability and repeatability outcomes.
Results: Thirteen full-text articles were thoroughly reviewed, including those identified through targeted keyword searches and the reference lists of these studies. The papers examined the translation of the English version of the OSDI-12 questionnaire into nine languages: Italian, Arabic, Chinese, Chilean Spanish, Japanese, Filipino, Farsi, Bahasa Melayu, and Brazilian Portuguese. Key details regarding the development, translation, and validation phases were summarized. Most of the included studies adhered to standard guidelines throughout the translation process to create a final version of the OSDI questionnaire. This was followed by clinical validation of the final translated version. The majority of the translated versions were assessed for internal consistency, reliability, test–retest repeatability, and discriminant validity.
Conclusions: The original English version of the OSDI was translated into validated versions to achieve a final version in nine different languages. The majority of the translated versions demonstrated high reproducibility and reliability. The different language versions of the questionnaire removed language barriers in informing the eye-care community, evaluating DES, and assisting physicians in advising and managing their patients more suitably. Therefore, the validated versions of OSDI can be used as tools for clinical practice and DES research. Validating the OSDI questionnaire in various languages is essential to eliminate the language barrier in the assessment of dry eye disease
Melatonin as a potential biomarker in diabetic retinopathy
Full text linkBackground: Diabetic retinopathy (DR) is a major complication of diabetes mellitus (DM). Melatonin protects against inflammation and oxidative stress. This review focuses on the literature comparing melatonin levels in patients with and without DR.
Methods: A thorough search of the PubMed/MEDLINE, Web of Science, and Embase databases was performed for articles published until April 2025. The inclusion criteria were studies reporting melatonin levels in patients with DR and control groups; studies involving human participants of any age, gender, or ethnicity; and investigations documented in scholarly publications. The exclusion criteria were as follows: animal studies; review articles; case reports; editorials; and conference abstracts; studies not available in English or lacking an English translation; and studies focusing on interventions altering melatonin levels rather than comparing levels between patients with DR and controls. Furthermore, we manually checked the reference lists of the included papers to identify any earlier series that were not initially found in our core search. The Newcastle-Ottawa Scale was used to evaluate study quality.
Results: Eight studies with 1004 participants published from 2011 to 2022 were included. The mean age of participants ranged from 39.9 to 72 years. Three studies assessed urinary melatonin excretion, three examined blood melatonin concentrations, one evaluated melatonin concentration in the aqueous humor, and one measured salivary melatonin levels. All samples were collected at night, except for three studies. All studies utilized enzyme-linked immunosorbent assay to measure melatonin concentration, except for the one study, which employed high-performance liquid chromatography. Numerous studies have indicated that patients with DM exhibit reduced melatonin levels relative to healthy controls, and that individuals with DR show lower levels than those without DR. Patients with proliferative DR exhibit reduced nocturnal urinary excretion of 6-sulfatoxymelatonin. Melatonin levels in the aqueous humor were elevated in patients with proliferative DR. Melatonin levels were negatively correlated with both the duration of DM and glycated hemoglobin levels.
Conclusions: The findings of this review suggest that patients with DM, particularly those with DR, exhibit altered melatonin production. Reduced systemic melatonin levels may correlate with increased risk and severity of DR. However, the majority of included studies had a case-control design, which hinders the ability to draw causal conclusions regarding the association between melatonin levels and DR. Moreover, confounding factors, including age, duration of DM, medication use, and lifestyle characteristics of participants, were not uniformly considered, and the limited sample sizes restrict the applicability of the results. Future investigations should emphasize longitudinal studies to clarify the temporal dynamics between melatonin levels and DR progression Additional investigations are required to clarify the function of melatonin in the pathogenesis of DR and its viability as a therapeutic target
Prevalence and demographic characteristics of strabismus in adults
Full text linkBackground: Strabismus is a common ocular disorder and a major cause of visual impairment and amblyopia. Its prevalence varies widely across populations and may differ by age, ethnicity, and underlying risk factors. Despite its clinical and psychosocial impact, data on strabismus in Iranian adults remain limited. This study aimed to determine the prevalence of strabismus and its associated demographic factors in southeastern Iran.
Methods: This cross-sectional analysis used baseline data from an adult eye cohort in Zahedan, southeastern Iran. A stratified cluster sampling design, based on socioeconomic status, was used to recruit residents aged 35–70 years between 2015 and 2019. Of 10 016 screened individuals, 9296 met inclusion criteria of Iranian nationality, greater than or equal 9 months of local residency, and completion of baseline assessments; participants with prior ocular surgery or active ocular disease were excluded. All participants completed a standardized ocular history questionnaire and underwent comprehensive visual assessment, including Snellen visual acuity testing, objective and subjective non-cycloplegic refraction, automated lensometry for habitual correction, external examination, slit-lamp biomicroscopy, and Goldmann applanation tonometry. Ocular alignment was evaluated using cover-uncover and alternate cover tests at distance and near vision. Strabismus was classified based on manifest deviations detected under best correction.
Results: Among 9296 adults, the overall prevalence of strabismus was 2.8% (262 cases; 95% CI: 2.5–3.2). The prevalences of exotropia, esotropia, hypertropia, intermittent exotropia, and intermittent esotropia were 1.3% (129 cases, 95% CI: 0.00–3.20), 0.2% (18 cases, 95% CI: 0.00–2.20), 0.3% (26 cases, 95% CI: 0.00–2.40), 0.8% (77 cases, 95% CI: 0.00–2.70), and 0.1% (12 cases, 95% CI: 0.00–1.80), respectively. Strabismus occurred most frequently in the 45–54-years age group (n = 92, 35.1%) and least often in those aged 65–75 years (n = 14, 8.3%). Women accounted for 61.8% (n = 162) of all cases, with all subtypes more common in women except for esotropia, which was equally distributed. Strabismus was most frequent among individuals with high school education (n = 89, 34.0%) and least common in those with university degrees (n = 46, 17.6%). The Sistani ethnic group showed the highest prevalence (n = 141, 53.8%) across all subtypes.
Conclusions: Strabismus affected 2.8% of adults, with exotropia the most common subtype. Prevalence varied by age, sex, educational level, and ethnicity, with the highest burden in adults aged 45–54 years and among the Sistani group. Most cases were previously undiagnosed, underscoring the need for targeted screening and early detection. Ongoing longitudinal follow-up will clarify incidence, progression, and treatment outcomes, supporting improved clinical decision-making, resource allocation, and long-term visual outcomes
Ocular surface lesions in clinical grades of Bell’s phenomenon
Full text linkBackground: Bell’s phenomenon, also known as the palpebral oculogyric reflex, is a critical reflex that protects the cornea. We developed an innovative, simple, and practical grading scale for Bell’s phenomenon that includes the inverse Bell’s phenomenon. Using this scale, we investigated the characteristics of Bell’s phenomenon among asymptomatic individuals in different age groups and examined the frequency of ocular surface lesions in asymptomatic and symptomatic participants with different grades.
Methods: Bell’s phenomenon was classified into five grades: grade +2 (strong positive), grade +1 (weak positive), grade 0 (no Bell’s phenomenon, no eye movement), grade –1 (weak inverse), and grade –2 (strong inverse). In this cross-sectional study, we randomly included 330 eyes of 165 asymptomatic, healthy, White Turkish individuals who attended the outpatient eye clinic, with a male-to-female ratio of 1:1.4, in the control group. These were categorized into four age groups: 4 – 20 years, 21 – 40 years, 41 – 60 years, and > 60 years. Eighty eyes from 40 patients with ocular surface lesions and absence of grade +2 Bell’s phenomenon were included in the symptomatic group.
Results: We detected higher frequencies of grade +2, +1, and 0 in individuals aged 4 – 40, 41 – 60, and > 60 years, respectively. There was a significant difference between age groups in the frequencies of different grades (P < 0.001). Pairwise analysis revealed a significantly lower frequency of grade +2 in the age group > 60 years compared with the 4 – 20 and 21 – 40 year groups (both P < 0.05). Grade +2 was the most frequent in both sexes. We detected grade 0 in 27.1% of men and 22.1% of women in the control group, with no significant difference in the frequencies of different grades between sexes (P > 0.05). We observed significant differences between grades with respect to the frequency of ocular surface lesions (P < 0.001). Pairwise analysis revealed a significantly higher frequency of ocular surface lesions in asymptomatic individuals with grade 0 and all four other grades (all P < 0.001). However, the frequency of ocular surface lesions was comparable between sexes (P > 0.05). Of the 40 symptomatic individuals, 28 (70%), 5 (12.5%), 4 (10%), and 3 (7.5%) had grade 0, +1, –1, and –2, respectively. The number of symptomatic patients was higher in grade 0 (n = 28) than in other grades (grade +1, –1, and –2: n = 12 patients), and these individuals had a higher frequency of ocular surface lesions (n = 38 lesions) than others (grade +1, –1, and –2: 7 lesions).
Conclusions: Using a simple, practical grading scale for Bell’s phenomenon that includes inverse Bell’s phenomenon, we observed that inverse Bell’s phenomenon is a reflex that may be present in healthy individuals and could have a protective effect on the eye, although not to such a degree as a strong Bell’s phenomenon. Our observations imply that bilateral conjunctival calcifications/Vogt’s limbal girdle may be associated with grades 0 and +1 Bell’s phenomenon. Further large-scale studies are needed to determine the frequency of Bell’s phenomenon in the general population using this innovative, simple, practical grading scale, and to identify the protective or injurious effect of each grade on the ocular surface