John C. Hwang

Autofluorescence Imaging and Spectral-Domain Optical Coherence Tomography in Incomplete Congenital Stationary Night Blindness and Comparison With Retinitis Pigmentosa

PURPOSEnTo test the hypothesis that the evaluation of retinal structure can have diagnostic value in differentiating between incomplete congenital stationary night blindness (CSNB2) and retinitis pigmentosa (RP). To compare retinal thickness differences between patients with CSNB2 and myopic controls.nnnDESIGNnProspective cross-sectional study.nnnMETHODSnTen eyes of 5 patients diagnosed with CSNB2 (4 X-linked recessive, 1 autosomal recessive) and 6 eyes of 3 patients with RP (2 autosomal dominant, 1 autosomal recessive) were evaluated with spectral-domain optical coherence tomography (SD OCT) and fundus autofluorescence (FAF). Diagnoses of CSNB2 and RP were confirmed by full-field electroretinography (ERG). Manual segmentation of retinal layers, aided by a computer program, was performed by 2 professional segmenters on SD OCT images of all CSNB2 patients and 4 age-similar, normal myopic controls. Seven patients were screened for mutations with congenital stationary night blindness and RP genotyping arrays.nnnRESULTSnPatients with CSNB2 had specific findings on SD OCT and FAF that were distinct from those found in RP. CSNB2 patients showed qualitatively normal SD OCT results with preserved photoreceptor inner segment/outer segment junction, whereas this junction was lost in RP patients. In addition, CSNB2 patients had normal FAF images, whereas patients with RP demonstrated a ring of increased autofluorescence around the macula. On SD OCT segmentation, the inner and outer retinal layers of both X-linked recessive and autosomal recessive CSNB2 patients were thinner compared with those of normal myopic controls, with means generally outside of normal 95% confidence intervals. The only layers that demonstrated similar thickness between CSNB2 patients and the controls were the retinal nerve fiber layer and, temporal to the fovea, the combined outer segment layer and retinal pigment epithelium. A proband and his 2 affected brothers from a family segregating X-linked recessive CSNB2 had a mutation, p.R614X, in the gene encoding calcium channel, α 1F subunit.nnnCONCLUSIONSnCSNB2 patients (X-linked recessive and autosomal recessive) had significantly thinner retinas than myopic controls. However, they demonstrated qualitatively normal SD OCT and FAF images, and therefore can be differentiated from RP patients with these techniques. Although ERG testing remains the gold standard for the diagnosis of these conditions, FAF and SD OCT systems are more widely available to community ophthalmologists, offer shorter acquisition times, and, unlike ERG, can be performed on the same day as the initial clinic visit. Therefore, as a supplement to ERG and genetic testing, we advocate the use of FAF and SD OCT in the examination of patients with CSNB2 and RP.

PERIPAPILLARY ATROPHY IN STARGARDT DISEASE

Objective: To demonstrate that Stargardt disease (STGD) can present with peripapillary atrophy. Methods: Retrospective case series. The medical records of 150 consecutive patients (300 eyes) were reviewed retrospectively from a STGD database from January 1999 to May 2007 at Columbia University’s Harkness Eye Institute. STGD patients demonstrating peripapillary atrophy were identified. Results: Three of 150 cases of STGD (2.0%) demonstrated peripapillary atrophy. Case 1 revealed peripapillary and central atrophy with heterozygous ABCA4 mutations P1380L and IVS40 + 5G>A. Case 2 demonstrated atrophic fleck lesions involving the peripapillary region and central atrophy with homozygous ABCA4 mutations P1380L and P1380L. Case 3 revealed bilateral central atrophy and pisciform fleck atrophy involving the peripapillary, macular, and peripheral regions with ABCA4 mutations P1380L and R2030Q. Overall, ABCA4 mutation P1380L was noted in 13 cases (8.7%), IVS40 + 5G>A in 6 cases (4.0%), and R2030Q in 1 case (0.7%). The remaining cases shared one common STGD mutation with Case 1, 2, and 3 (P1380L or IVS40 + 5G>A) and demonstrated classic STGD findings of central atrophy and varying presence of peripheral flecks without peripapillary lesions. Conclusion: STGD can present with peripapillary atrophy. This relatively uncommon phenotype may arise from specific combinations of STGD ABCA4 mutations rather than single mutations.