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This research lies in the significant global visual impairment burden, where 2.2 billion people suffer from some form of visual impairment, with one billion of these cases being preventable or treatable causes like glaucoma, Age-related Macular Degeneration (AMD), and diabetic retinopathy, all of which benefit from early detection via retinography. Brazil, in particular, faces an unbalanced geographical distribution of ophthalmologists, with a severe deficit in the Northern region, especially in communities outside the state capitals. Traditional fundus evaluation instruments are expensive, difficult to handle, and logistically challenging to transport, making them inaccessible in resource-limited areas. The emergence of new smartphone-based, portable, non-mydriatic fundus cameras offers a solution by enabling the capture of high-quality retinal images more affordably and easily. Combined with telemedicine and cloud-based data records, this technology allows specialized ophthalmologists to remotely analyze images and provide reliable diagnoses, offering a promising opportunity to address ocular health inequalities in vulnerable, unaided populations. This study, therefore, sought to evaluate the retina and investigate the prevalence of retinal findings in a semi-isolated riverside community in the Amazon Forest, a region with low health access, to demonstrate the potential of telemedicine and portable devices in enhancing ocular health.

A cross sectional study was conducted in the community of Calama – Rondônia, Brazil, which is a 2,000 people riverside community in the Amazon Forest located around 15 hours by boat away from the closest ophthalmology service. The STROBE reporting guideline was followed [13]. The study was performed in accordance with the ethical standards of The Declaration of Helsinki and approved in the Local Research Ethics Committee (number 5.325.976), informed consent was verbal. Participants included adults randomly selected in home visits or at the local general care clinic during January-February 2022; to avoid bias, it was excluded from the sample patients under 18 years old, with anterior segment opacities, and who looked for the clinics with known eye diseases. In siting position, two retinal photos were captured from each eye: i) posterior pole, and ii) optic disc. After photo acquisition, participants were questioned about age, sex, and self-reported comorbidities, no ethnic information was collected during the study. All photos and data were automatically sent to an online encrypted data base (EyerCloud, Phelcom Thecnologies®, SP-Brazil). Photos were captured by four previously trained 5th year medical students using a portable non- mydriatic smartphone-based fundus camera (Eyer, Phelcom Thecnologies®, SP-Brazil). Interns were trained in a four-hour lection including theoretical aspects (e.g.: physics of the device, ophthalmological basic anamneses and exam, and retinal pathology) and practical activity in a simulation-based scenario. A single retina specialist located more than 3,000km away received all data remotely, checked all exams for retinal alterations, and, through the data base, sent back the signed results. All participants were properly referred or oriented according to the final diagnosis given through telemedicine (Figure 1). Transportation of all referred patients was guaranteed by the local health secretary. Epithelial changes were considered as areas of altered hyper or hypo pigmentation in the epithelium without visual alteration or known cause. Chorioretinal scars were considered as areas of pigmentary change or fibrosis resulting from an uncomplete healing of the retina, showing a possible participation of the retinal pigmented epithelium (RPE) in process that affect the retina and choroid. Dry AMD was considered the presence of drusen in the macula without neovascularization. Enlarged optic discs were considered disc relation > 0.50. Hypertensive retinopathy was considered as widening of the arteriole reflex, arteriovenous crossing signs, and copper or silver wire arterioles (copper or silver colored arteriole light reflex), or constricted and tortuous arterioles, retinal hemorrhage, or hard exudates in patients with known history of arterial hypertension. Non proliferative diabetic retinopathy was considered as the presence of microaneurysms, dot-blot hemorrhages, cotton wool spots and hard exudates without neovascularization in patients with known diabetes. Statistical analyses were performed using IBM SPSS® 28.0.1 (IBM, Inc, Chicago, IL-USA). Continuous variables were compared between groups with Mann–Whitney U test for non-parametric independent samples, and nominal variables were compared with Chi-squared test. Proportion 95% Confidence Intervals (CI) were calculated considering a=0.05 and binomial distributions.

During the study, 122 individuals were screened for retinal alterations, 15 were excluded for not meeting including criteria (Figure 2A). Final sample was composed by 107 participants, aged mean 52±17.7 years (range 18 to 88), and 57.9% female. Comorbidities were found in 46.7% of the sample and were systemic arterial hypertension (SAH), Type 2 Diabetes Mellitus (DM2), and dyslipidemia, 22.4% had more than one comorbidity associated. Patient’s demographics are shown in Table 1, altered retina were considered patients with a retinal alteration in fundus photography in at least one eye. Most of the population did not have any identifiable retinal alterations, 62.6%, CI [53.2, 71.3], however findings were detected in 37.4%, CI [28.7, 46.8], of the sample. A large set of alterations were identified, ranging from non-visual threatening to severe blindness (e.g., inferior temporal persistent myeline fibers vs. large macular chorioretinal scar; Figure 2B-C). Interestingly, the three main retinal findings were epithelial changes (10.3%, CI [5.6, 17.1]), chorioretinal scars (8.4%, CI [4.2, 14.8]), and dry Age-related Macular Degeneration (dAMD; 7.5%, CI [3.6, 13.6]). In lower rates, enlarged optic disc (2.8%, CI [0.8, 7.3]), hypertensive retinopathy (2.8%, CI [0.8, 7.3]), and non-proliferative diabetes retinopathy (NPDR; 1.9%, CI [0.4, 5.9]) were also identified. Other alterations appeared only once, 0.9%, CI [0.1, 4.3]—angioid streaks, fundus miopicus, optic disc nevus, and persistent myeline fibers (Figure 2D). All patients that showed NPDR had confirmed Type 2 Diabetes Mellitus (DM2), the prevalence of NPDR among DM2 participants was 8.0%, CI [1.7, 23.3]. Other ophthalmological findings that were not in the retina (e.g., refractive errors, pterygium, cataract, etc) were not considered in the study. Among the sample, participants with retinal alterations were significantly older (p<0.001), however, as expected, when adjusted by age and in pairwise comparison with retinal findings, only dAMD had statistical significance (p0.05). SAH was the only comorbidity that showed higher prevalence among participants with retinal findings (52.5%; CI 37.3, 67.3, p=0.008). Sex, DM2, dyslipidemia and smoking showed no impact on the findings (p>0,05).

In this study, we showed that, through relatively low-cost and portable devices, distant high specialized professionals can guarantee and support effective clinical decisions in remote areas with low health access. However, it is possible to conclude that maintaining assistance after initial implementation is still a challenge, since the visit of trained health professionals is periodic, and some conditions demand frequent follow-up. We suggest enhancing medical education in the recognition of ocular pathologies, training local non-specialized health professionals for risk assessment, device handling, and data base use to ensure early diagnosis and follow-up after project implementation. Apart from that, we also suggest the development of new research aiming unexplored portable devices (e.g., OCT, visual field) and larger investigations with a broader spectrum of exams to support public policies in blindness prevention.