Retinitis Pigmentosa in Onitsha, Nigeria

Retinitis pigmentosa describes a heterogenous group of progressive hereditary degeneration of the photoreceptor-retinal pigment epithelium complex with varying clinical manifestations. Although studies on the epidemiology of blindness and visual impairment in Nigeria have documented the contribution of retinitis pigmentosa, detailed study of the prevalence, incidence, and pattern of retinitis pigmentosa in Nigeria are few.

The aim of this study was to describe the relative frequency rate and pattern of retinitis pigmentosa among new patients at the Guinness Eye Center Onitsha Nigeria.

Case files of new patients with clinical features of retinitis pigmentosa seen over a 6-year period were reviewed. Information on age, sex, and associated clinical features were extracted into a standard proforma and analyzed.

Thirty-seven (0.6%) of 5876 new patients had retinitis pigmentosa. There were 25 (67.6%) males and 12 (32.4%) females with an age range of 4-76 years; the median age was 33 years. Family history suggested autosomal dominant inheritance in 15 (40.6%) patients, autosomal recessive inheritance 4 (10.8%), X-linked inheritance 9 (24.3%), and 9 (24.3%) sporadic. Six (16.2%) patients were blind (acuity <3/60) and 22 (59.5%) patients had visual impairment (acuity <6/18). Eight (21.6%) patients had coexistent deafness (syndromic retinitis pigmentosa) including two (5.4%) cases of Usher syndrome.

The relative frequency rate of retinitis pigmentosa among new patients in our hospital is low but the associated visual and otologic incapacitation are enormous. A prospective study incorporating molecular genetics would more exactly determine the inheritance pattern and the common genes of retinitis pigmentosa in Nigerians.