Outcomes of the retinopathy of prematurity screening and treatment in Mongolia Background: Retinopathy of prematurity (ROP) is a disease characterized by abnormal retinal vasculature that can have devastating visual consequences. Despite evidence that early detection and treatment can prevent blindness, ROP remains a leading cause of pediatric blindness worldwide. We aimed at investigating the outcomes of ROP screening, intravitreal anti–vascular endothelial growth factor (VEGF) and laser surgery in the treatment ROP and describe an evidence-based and specific process for identifying birth weight and gestational age screening guidelines in Mongolia utilizing telemedicine. Materials and methods: This was a retrospective of prematurity infants screened ROP from 2012 September to July 2020 and prospective cohort study of premature infants with treatment-requiring ROP who received intravitreal injections, laser surgery and combined therapy from 2015 December 01 to January 31, 2017. Demographic factors, diagnosis and clinical course were recorded in a de-identified manner using REDCap, a secure, web-based platform to collect image and demographic data. The IRB approved the study protocol not requiring parental consent due to the de-identified nature of the data which was used for program monitoring purposes. Indirect ophthalmoscopy and Retinal imaging was performed using RetCam (Natus Medical, Pleasanton, CA) and images were uploaded to the web-based platform which could be accessed by the Mongolian ophthalmologist for reference. Each eye was evaluated by the local Mongolian ophthalmologist for the presence or absence of ROP, zone of vascularization, stage, plus disease, and aggressive posterior ROP (AP-ROP). The diagnosis and classification of ROP for this current study were determined by examination using indirect ophthalmoscopy, and treatment plans were determined according to the International Classification for ROP and the Early Treatment for ROP Study (ET-ROP).2,13 Regression analysis to determine association between BW and GA and the development of ROP. Results: A total of 9126 premature infants with BW ≤ 2500 g and/or GA ≤ 36 weeks were screened for ROP during the study period. 327 (3.5%) of the 9126 infants screened required treatment. The193 infants who received ROP screening had a mean GA of 30.09 ± 1.7 weeks, and mean BW of 1500.3 ± 125.42g. The BW of infants in this study ranged from 750g to 2000g, and the GA at birth ranged from 25 to 35 weeks. The BW of infants in this study ranged from 750g to 2000g, and the GA at birth ranged from 25 to 35 weeks. There were 96 boys (49.7%) and 97 girls (50.3%). Among infants receiving treatment, the highest BW was 2000g (born at 31 weeks GA), and the oldest was 34 weeks (with a BW of 1300g). The distribution of birth weight and gestational age in Mongolia was similar to other low-middle income countries, with higher birth weight and older gestational age. As birth weight and gestational age decreased, relative risk of developing ROP increased. Conclusions: After treatment, resolution of ROP was noted in approximately 90 % of the patients who had treatment-requiring ROP. 10 % of patients treated with IVB, IVR, Laser surgery and combined therapy however, did not respond and progressed to retinal detachment. This prospective study provides information about the development of ROP in preterm infants in the capital city of Mongolia. The distributions of BW and GA among infants developing ROP in Mongolia differ from those found in higher-income countries, and are comparable to other low and middle-income countries. We used a secure, web-based data collection and retrieval system that could be extended to multiple countries, which is now equipped with a telemedicine platform enabling remote grading of fundus images.