Abstract
Purpose: :
To describe the disease progression in ten patients aged 9 to 60 from a single family segregating autosomal dominant macular dystrophy linked to the Arg172Trp RDS mutation.
Methods: :
Evaluation of the patients included visual acuity testing, fundus and autofluorescence photographs, Goldmann visual fields, optical coherence tomography (Zeiss, OCT3), full field (ISCEV protocol) and multifocal ERGs.
Results: :
Patients were asymptomatic with normal visual acuity until their early twenties, although a small perifoveal ring of increased autofluorescence was already detected. From 20 to 40 years of age, the visual acuity decreased moderately (mean value: 20/30). The macula showed pigment epithelium granularity and whitish deposits but the fovea looked unaffected. The perifoveal ring of increased autofluorescence was extending peripherally and included small points of decreased autofluorescence (first stage of atrophy). On OCT, there was first a decrease in thickness of the foveal margin and perifoveal area, later followed by a decrease in foveolar thickness. Accordingly, the multifocal ERG disclosed a predominant amplitude reduction in the perifoveal area. Full field ERG showed decreased 30-Hz flickers and red photopic responses while scotopic responses remained normal. By 40 years of age, visual acuity dropped to 20/400 with occurrence of an extended macular atrophy which reached the temporal superior and inferior arcades by 50 years of age.
Conclusions: :
This observation shows that there is a progressive peripheral extension of the macular lesions outside the fovea, while the fovea itself is minimally affected until the 4th decade. Later on, severe visual loss occurred, caused by a large macular atrophy. This suggests that the pathogenic process affects first perifoveal photoreceptors (cones and rods), resembling the progression of perifoveal lesions observed in some cases of Stargardt macular dystrophy.
Keywords: macula/fovea • genetics • degenerations/dystrophies