Drusen ooze: Predictor for progression of dry age-related macular degeneration

Background To evaluate natural history of drusen ooze and its role as a predictor for progression of dry age-related macular degeneration (AMD) longitudinally. Methods Multi-centric retrospective observational case series of 72 eyes (72 patients) with dry AMD with a minimum follow-up of 4 years. Drusen types were identified on volume scans on optical coherence tomography (OCT) and were characterized for occurrence of drusen ooze at baseline until last visit. Drusen ooze was defined as hyperreflective dots overlying a collapsing drusen or pseudodrusen, or hyperreflective RPE above drusen or isoreflective dots at the level of outer nuclear layer. The consequent incidence of incomplete retinal pigment epithelium and outer retinal atrophy (iRORA), complete retinal pigment epithelium and outer retinal atrophy (cRORA), and neovascular AMD (nAMD) were evaluated statistically. Results In total, 72 eyes with a mean follow-up of 68.89 (+/- 25.57 months) were studied. At presentation, 11 eyes (15.3%) had a single drusen type, whereas 61 eyes (84.7%) had mixed drusen. Reticular pseudodrusen were most common (84.7%) followed by soft drusen (66.6%). Drusen ooze was seen in 47 eyes (65.2%) at presentation. The presence of drusen ooze at baseline (p < 0.01) and baseline best corrected visual acuity (BCVA) (p = 0.04) significantly correlated with development of iRORA and cRORA. In total, 14 eyes progressed from iRORA to cRORA over a mean follow up of 29.14 (+/- 24.33) months. Odds of progression to iRORA or cRORA were 20.3 times greater for eyes with drusen ooze at baseline (95% C.I., 4.4-94.2). Conclusions In dry AMD, drusen ooze is a useful sign for predicting progression to iRORA and cRORA over time.