title: Autofluorescence imaging and spectral-domain optical coherence tomography in incomplete congenital stationary night blindness and comparison with retinitis pigmentosa.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
authors.affiliation: Department of Ophthalmology, Columbia University, New York, New York 10032, USA.
authors.forename: Royce W S
authors.initials: RW
authors.lastname: Chen
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Greenberg
authors.forename: Margot A
authors.initials: MA
authors.lastname: Lazow
authors.forename: Rithu
authors.initials: R
authors.lastname: Ramachandran
authors.forename: Luiz H
authors.initials: LH
authors.lastname: Lima
authors.forename: John C
authors.initials: JC
authors.lastname: Hwang
authors.forename: Carl
authors.initials: C
authors.lastname: Schubert
authors.forename: Alexandra
authors.initials: A
authors.lastname: Braunstein
authors.forename: Rando
authors.initials: R
authors.lastname: Allikmets
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Tsang
mesh_terms: D000328:Adult; D000368:Aged; D020746:Calcium Channels, L-Type / Q000235:genetics; D002648:Child; D003430:Cross-Sectional Studies; D004596:Electroretinography; D015785:Eye Diseases, Hereditary; D005451:Fluorescein Angiography; D040181:Genetic Diseases, X-Linked; D006801:Humans; D008297:Male; D009216:Myopia / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D009755:Night Blindness / Q000175:diagnosis* / Q000235:genetics; D011446:Prospective Studies; D012160:Retina / Q000473:pathology*; D012174:Retinitis Pigmentosa / Q000175:diagnosis* / Q000235:genetics; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology
chemical_list: C113330:CACNA1F protein, human; D020746:Calcium Channels, L-Type