Conjunctival Microbiota in retinal diseases requiring anti-VEGF therapy: Age-related macular degeneration, diabetic retinopathy, and retinal vein occlusion

Purpose This study aimed to investigate the conjunctival microbiota of patients requiring intravitreal injections due to diabetic retinopathy (DR), age-related macular degeneration (AMD), and retinal vein occlusion (RVO). Methods A total of 182 participants (46 DR, 71 AMD, 16 RVO, and 49 controls) were enrolled between August and November 2024. Conjunctival swabs were collected from both eyes under sterile conditions prior to injection and cultured on 5% sheep blood and chocolate agar. Microorganisms were identified using Vitek MS. Results No significant differences were observed among the groups in overall microbial growth frequency (all p > 0.05). Gram-negative bacteria, fungi, and polymicrobial growth were more frequently detected in DR and AMD patients, suggesting a trend toward greater microbial diversity, although these differences were not statistically significant. Conclusion DR and AMD patients exhibited higher prevalence of gram-negative, fungal, and polymicrobial colonization. These findings underscore the importance of strict aseptic preparation, povidone-iodine disinfection, and targeted prophylactic strategies to minimize post-injection infection risk in high-risk populations.