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

Abstract

PURPOSE To 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. DESIGN Prospective cross-sectional study. METHODS Ten 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. RESULTS Patients 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. CONCLUSIONS CSNB2 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.

Clinical Characteristics, Mutation Spectrum, and Prevalence of Åland Eye Disease/Incomplete Congenital Stationary Night Blindness in Denmark

“…17–19 Segmentation of SD-OCTs of the retinal layers in five individuals with X-linked and autosomal recessive CSNB2 patients has shown thinning of both inner and outer retinal layers, compared with those of myopic controls. 35 While we could not combine the data from the Spectralis and Cirrus instruments owing to different segmentation methods, the qualitative retinal thinning was visible in many subjects (Fig. 3E).…”

“…The thickness of the subfoveal choroid in patients with AED is substantially lower than in healthy subjects, and the difference exceeds by far the effect of myopia. 35,38 …”

Bilateral Concordance of the Fundus Hyperautofluorescent Ring in Typical Retinitis Pigmentosa Patients

“…Fundus autofluorescence (AF), commonly used in the diagnosis and follow-up in patients with retinitis pigmentosa, can be used to identify disease progression over time. 15–20 AF has the ability to image structural features such as the hyperautofluorescent ring, seen in 59–94% of RP patients including in simplex and syndromic RP, and common in every inheritance pattern. 21–23 This ring is a structural indicator for RP progression and has been reported to correlate well with other structural and functional assessments, such as optical coherence tomography (OCT), pattern electroretinograms (ERG), multifocal ERGs, microperimetry and visual fields.…”

Assessing Retinal Structure in Complete Congenital Stationary Night Blindness and Oguchi Disease

“…33 A recent investigation using spectral-domain optical coherence tomography (SD-OCT) demonstrated thinned retinas in five patients with incomplete congenital stationary night blindness, three of whom had a mutation in the CACNA1F gene. 34 Despite being more rare than congenital stationary night blindness without fundus abnormalities, anatomical studies in patients with Oguchi disease are rather numerous. Usui et al reported diffuse, fine white particles on helium-neon laser imaging in the light-adapted retina, which disappeared on dark adaptation and reappeared gradually on exposure to light suggesting that accumulation of an abnormal product in the outer retina causes the golden metallic fundus appearance.…”