A 47-year-old woman noted slightly reduced visual acuity in both eyes, progressing over the past 2 years. Family history of retinal disease was negative. There was a history of anxiety and depression, for which she took sertraline hydrochloride for 7 years but stopped 2 years prior to the onset of her visual symptoms. Best-corrected visual acuity with low myopic correction was 20/40 OD and 20/30 OS. Anterior segment examination results were normal. Fundus examination () revealed symmetric macular pigment irregularity with small drusenlike deposits. Imaging with the Spectralis HRA (Heidelberg Engineering, Heidelberg, Germany) showed nearly confluent hypofluorescence centrally in both eyes (). Visual fields had bilateral symmetric central and paracentral scotoma (). Multifocal electroretinography showed central depression in both eyes (). Macular thickness was decreased (central thickness = 188 μm OD; average thickness = 230 μm OD) with normal retinal nerve fiber layer thickness as measured on the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, California). Data were consistent with decreased visual function associated with an outer retinal disruption.
Figure 1 Clinical presentation of the patient. Results are shown for the right eye, although all findings were seen bilaterally. A fundus photograph (A) and an autofluorescence image with asterisks indicating the locations imaged with adaptive optics shown in (more ...)
High-resolution images of the macula were obtained using a Bioptigen spectral-domain (SD) OCT equipped with a 186-nm broadband light source (Bioptigen, Durham, North Carolina). Images of the cone photoreceptor mosaic were obtained using a newly developed high-speed, flood-illuminated, AO ophthalmoscope. Images were analyzed using custom Matlab programs (Math-works, Natick, Massachusetts) and ImageJ software (National Institutes of Health, Bethesda, Maryland).
The high-resolution SD-OCT images from the patient’s right eye revealed a disruption of the inner segment–outer segment layer in most parafoveal locations with preservation of cone remnants in the central fovea (). The external limiting membrane was intact, indicating the presence of remaining inner segment structures, although measurement of the outer nuclear layer revealed significant thinning compared with 97 healthy control subjects ().
Figure 2 Evidence for cone photoreceptor degeneration. A, Comparison of the patient’s outer nuclear layer (ONL) thickness (dashed line) with the average ONL thickness in 97 healthy control subjects reveals significant thinning. Solid lines indicate ±2 (more ...)
The AO images revealed significant photoreceptor mosaic heterogeneity (). While some structures were consistent with normal cone photoreceptor appearance, these were rare. Of particular interest were patches of hexagonally packed structures with a bubble wrap appearance. The density of these structures was less than 50% of a normal cone array for this retinal location.4
A similar morphological appearance was reported in a patient with X-linked cone-rod dystrophy.4
Finally, craterlike lowly reflecting patches were seen interleaved among variably sized reflecting structures. While these changes in reflectivity may have their origins in the pigment irregularities, precise correlation was not possible owing to the low resolution of the autofluorescence image.