Jacob Moysés Cohen

Purpose: To determine the indications and epidemiological characteristics of corneal transplant recipients at a referral center in Amazonas, Brazil, and to evaluate postoperative visual outcomes. Methods: This retrospective, descriptive, observational study included adult patients who underwent corneal transplantation performed by a single surgeon at the Instituto de Oftalmologia de Manaus between 2013 and 2023. Demographic characteristics, occupation, comorbidities, surgical indications, graft type, and best-corrected visual acuity at baseline and 12 months postoperatively were analyzed. Results: A total of 413 corneal transplantations were performed, predominantly in male patients (64.4%) aged 41-70 years (43.3%). Leucoma was the most common indication (26.2%), followed by perforated corneal ulcers (21.1%), bullous keratopathy (17.9%), and keratoconus (10.7%). Penetrating keratoplasty accounted for 94.9% of all procedures. Optical keratoplasty was the most frequently performed procedure (76.3%), followed by tectonic (22.0%) and therapeutic (1.7%) keratoplasty. At 12 months postoperatively, visual improvement was greatest among patients who underwent optical keratoplasty, particularly those with keratoconus, bullous keratopathy, and leucoma. Functional vision (≤0.3 logMAR) was achieved in 32.6% of eyes overall and in 40.3% of eyes that underwent optical keratoplasty. The number of transplantations declined after 2019, coinciding with the COVID-19 pandemic. Conclusions: This study represents the largest retrospective series of corneal transplantations in Amazonas and one of the few such studies from Northern Brazil. The predominance of leucoma and infectious corneal perforation reflects regional socioeconomic and occupational vulnerabilities. Although visual outcomes improved significantly after transplantation, visual recovery was limited by the advanced stage of disease at presentation. These findings underscore the need to expand access to early diagnosis, strengthen eye banking and donor tissue procurement systems, and increase the adoption of lamellar keratoplasty techniques to optimize visual outcomes in the Amazon region.

This pilot study evaluated the diagnostic accuracy of a deep learning model for detecting pterygium in anterior segment photographs taken using smartphones in the Brazilian Amazon. The model's performance was benchmarked against assessments made by experienced ophthalmologists, considered the clinical gold standard. In this cross-sectional study, 38 participants (76 eyes) from Barcelos, Brazil, were enrolled. Trained nonmedical health workers captured high-resolution anterior segment images using smartphones. These images were analyzed using a deep learning model based on the MobileNet-V2 convolutional neural network. Diagnostic metrics-including sensitivity, specificity, accuracy, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve-were calculated and compared with the ophthalmologists' evaluations. The deep learning model achieved a sensitivity of 91.43%, specificity of 90.24%, positive predictive value of 88.46%, negative predictive value of 92.79%, and an area under the curve of 0.91. Logistic regression revealed no statistically significant association between pterygium and demographic variables such as age or gender. The deep learning model demonstrated high diagnostic performance in identifying pterygium in a remote Amazonian population. These preliminary findings support the potential use of artificial intelligence-based tools to facilitate early detection and screening in underserved regions, thereby enhancing access to ophthalmic care.

This study evaluated macular thickness using spectral-domain optical coherence tomography in healthy participants from a population-based eye survey. The Brazilian Amazon Region Eye Survey was a population-based study assessing the prevalence and causes of visual impairment, blindness, and ocular diseases in adults aged ≥45 years from urban and rural areas of Parintins. A subgroup was selected based on inclusion criteria for both eyes: best-corrected visual acuity ≥20/32, normal eye examination results, and no prior ocular surgery. Scans were performed using the iVue optical coherence tomography device. Measurements were taken from the nine subfields defined by the Early Treatment Diabetic Retinopathy Study, examining the full retina as well as the inner and outer retinal layers. Associations of retinal thickness with age and sex were also analyzed. Statistical significance was set at p≤0.05. In total, 70 healthy participants (25 males), aged 45-65 years (mean=52 ± 5), were included. Mean central foveal thickness was 248.71 ± 18.73 μm. A significant age-related reduction in macular thickness was observed, particularly in the inner superior parafovea (p=0.036), nasal perifovea (p=0.001), superior perifovea (p=0.028), outer layer of inferior parafovea (p=0.049), and the inferior perifovea of the full retina (p=0.029). Males showed significantly greater thickness in the outer layer, especially in the outer parafovea (p=0.004) and perifovea (p<0.0001). This study established normative macular thickness values for healthy older adults in the Brazilian Amazon region using spectral-domain optical coherence tomography. Age and sex were found to significantly influence macular thickness and should be considered when interpreting measurements. These data will support future studies of retinal diseases in this population.

Purpose: To determine the prevalence and causes of visual impairment and blindness in adults aged 45 years and older from Parintins, Brazilian Amazon Region. Methods: A random cluster sampling method was used to identify subjects 45 years of age and older from urban and rural census sectors of Parintins city, Amazonas State, from March 2014 to May 2015. Participants underwent a detailed ocular examination, including presenting (PVA) and best corrected visual acuity (BCVA). The main cause of PVAResults: A total of 2384 subjects were enumerated and 2041 (85.6%) examined. The prevalence of presenting mild visual impairment – MiVI (Conclusions: Most cases of visual impairment in Parintins are either preventable or treatable, and public health initiatives should target cataract surgical services and refraction with spectacle provision.