Clinical variations in assessment of bull's-eye maculopathy.

OBJECTIVES: To evaluate the phenotypic variation in bull's-eye maculopathy and seek possible correlations between functional loss and clinical appearance.
METHODS: From January 1, 1999, to September 30, 2000, we prospectively examined patients with bull's-eye lesions. Age of onset, duration of symptoms, visual acuity, clinical appearance, and autofluorescence images were recorded, the area of atrophy measured, and electrophysiologic investigations performed.
RESULTS: Forty-seven patients, including 6 sibling pairs, met the study entry criteria. On the basis of autofluorescence imaging, 3 distinct groups were identified. Group 1 showed a distinct ring of increased autofluorescence surrounding an area of decreased autofluorescence. In group 2, the ring of increased autofluorescence was not present. Group 3 displayed a speckled appearance within the affected area. All patients had evidence of central sparing in an area of centrally increased autofluorescence. There was significant correlation with the age of onset, visual acuity, and duration of disease. Electrophysiologic tests revealed that 28 patients had macular dysfunction only, 14 had cone-rod dystrophy, 3 had rod-cone dystrophy, and only 2 (monozygotic twins) had cone dystrophy. The correlation between electrophysiologic and autofluorescence data was poor. The sibling pairs had concordant autofluorescence appearance, but electrophysiologic grouping differed in 2 pairs.
CONCLUSIONS: Bull's-eye maculopathy represents a heterogeneous group of disorders. The clinical appearance was not helpful in assessing the degree of retinal dysfunction. The difference in qualitative characteristics of functional loss between siblings implies that these attributes do not necessarily reflect the influence of the primary mutation.