Outcome Measures: The primary outcome measure related to the safety and tolerability of serial ocular instillations of topical interferon gamma-1b will be assessed by the number and severity of adverse events (AEs) related to the investigational product and the number of withdrawals. Secondary efficacy outcomes include changes in best-corrected visual acuity (BCVA), central retinal thickness and maximum lesion volume as measured on optical coherence tomography (OCT), leakage as observed on fluorescein angiograms (FA), autofluorescence patterns as observed on fundus autofluorescence (FAF) imaging and mean macular sensitivity as assessed by microperimetry.