blindness. Retinitis pigmentosa is one such common disease that is associ­ated with rod dysfunction giving symptoms of night blindness (nyctalopia) early on and later severe peripheral vision loss. An electroretinogram is the diagnostic modality of choice in such patients, especially early on during the disease course when clinical exam may be unremarkable or only mildly abnormal. In patients with this disease, OCT will show outer retinal atro­phy and, in some patients, cystoid macular edema — a marker of retinal disease and dysfunction (Figure 16(a) and (b), RP with outer retinal loss, CME s/p treatment with topical CAIs). Another hereditary retinal degener­ation, Stargardt’s disease affects the macula, responsible for central visual dysfunction. Stargardt’s disease is characterized by hyperautofluorescent flecks called lipofuscin which deposit along the RPE and secondary lead to outer retinal disruption and atrophy (Figure 17, Stargardt’s pt). Stargardt’s disease is the most common hereditary maculopathy seen in children.

The OCT appearance shows intraretinal cystic spaces in the inner nuclear and outer plexiform layers. There may be the resolution of these changes seen with cessation of the medication (Figure 19(a) and (b), CME from Fingolimod, resolved following drug cessation).