<qa>  What is the first phase of the study?This is a single-center, prospective, uncontrolled, unmasked pilot Phase III study of the safety, tolerability and possible efficacy of IFN gamma-1b in participants with RCD and ESCS and macular cystic changes. One eye of up to five participants with RCD with significant macular cystic changes and up to five participants with ESCS with significant macular cystic changes evidenced by optical coherence tomography OCT 275 microns central macular thickness andor disruption of foveal contour will receive topical IFN gamma-1b instilled as drops on the cornea. The initial stage of the study will include two participants from each disease category. Once all four participants have completed the 8-week visit, enrollment will be halted. Safety Adverse Event Review Committee members unaffiliated with the study will review the data as a preliminary assessment of safety and efficacy and to determine whether enrollment should continue. If the committee determines enrollment will continue, three additional participants with RCD and three participants with ESCS will be enrolled. The study will be completed once the final participant has received one year of follow-up. 