Purpose

This study is designed as a double-masked, randomized, placebo-controlled, clinical study to evaluate the efficacy and safety of subcutaneous (SC) administration of RPh201 in participants with previous NAION. All participants enrolled in Cohort A of the study will have a documented history of NAION for at least 12 months and at most, five years prior to enrollment. Participants enrolled in Cohort B of the study will have a documented history of NAION for at least 6 months and at most, three years prior to enrollment.