RETINITIS-PIGMENTOSA INVERSA

Background. Retinitis pigmentosa (RP) is one of the most common inheri ted retinal diseases, with a prevalence of about 1 in 3500 to 4500. Re tinitis pigmentosa inversa is a rare variant of this disorder characte rized by areas of choroidal degeneration with pigment migration and bo ny spicule formation in the macular area. In contrast tee more typical forms of RP, this anomaly destroys central vision, leaving peripheral vision intact. Case Report. A 47-year-old white male was followed for about 7 years with evidence of progressive retinal pigment epithelial atrophy and hyperpigmentation affecting both maculae. Since 1970, he had noted difficulty seeing at night as well as an acquired hearing de ficit that appeared to be getting worse, ultimately impairing his abil ity to safely drive a truck, Medical history was positive for either c hloroquine or hydroxychloroquine use for 2 to 3 years as malaria proph ylaxis while he served in Vietnam. In addition, his father in Louisian a had visual loss of unknown cause. During the 7-year period, the cond ition progressed rapidly. The patient became virtually blind secondary to visual acuity loss with dense central and paracentral scotomas. Th e peripheral visual fields remained intact. After several years of ext ensive examinations, including laboratory, electroretinography, and ge netic testing, a definitive diagnosis of RP inversa was made, Discussi on. WP inversa is a rare form of tapetoretinal degeneration that is ch aracterized by decreased central vision with normal peripheral vision. A recessive form of inheritance has been postulated but never substan tiated. Although there is currently no treatment, recent studies have indicated that 15,000 IU of vitamin A palmitate daisy may slow the pro gression of retinitis pigmentosa; however, it is unknown whether this treatment would be effective for the inverse form of RP. Differential diagnoses include Leber's congenital amaurosis, central gyrate atrophy , central areolar choroidal sclerosis, progressive cone-rod dystrophy, syphilitic retinopathy, retinal toxicity from phenothiazine use, and chloroquine/hydroxychloroquine retinopathy.