title: Fluorescence adaptive optics scanning laser ophthalmoscope for detection of reduced cones and hypoautofluorescent spots in fundus albipunctatus.
abstract: OBJECTIVE
  Fundus albipunctatus (FA) is a form of congenital stationary night blindness characterized by yellow-white spots, which were classically described as subretinal. Although night blindness and delayed dark adaptation are hallmarks of this condition, recent studies have described a macular phenotype, particularly among older patients. Using a fluorescence adaptive optics scanning laser ophthalmoscope (FAOSLO), this study provides in vivo morphologic data at the cellular level in FA.
  
  
  OBJECTIVE
  To study the cone photoreceptors and the albipunctate spots in FA at single-cell resolution.
  
  
  METHODS
  A woman in her 30s with FA underwent a complete ophthalmic examination, including conventional imaging tests, at the University of Rochester. A FAOSLO was used to obtain infrared reflectance images of the cone mosaic at the central fovea and along the superior and temporal meridians to 10° eccentricity. Cone density was measured at the foveal center, and cone spacing was calculated in sampling windows eccentrically. In the area of the albipunctate spots, autofluorescence FAOSLO images (excitation, 561 nm; emission, 624 Δ 40 nm) were simultaneously obtained.
  
  
  METHODS
  Structural appearance of cones, cone density and spacing, and reflectance and autofluorescence of albipunctate spots.
  
  
  RESULTS
  Cone density was reduced to 70% of the lower limit of the normal range at the foveal center (78.7 × 10(3) cones/mm(2); mean [SD] reference range, 199 [87] × 10(3) cones/mm(2)), and cone spacing was increased eccentrically to 10° (sign test, P = .045). Individual cone central core reflectances appeared dim, suggesting loss of photoreceptor outer segments. The albipunctate spots were hypoautofluorescent. No photoreceptors or retinal pigment epithelium cells were identified at the locations of the albipunctate spots.
  
  
  CONCLUSIONS
  Although the predominant clinical symptom of night blindness and the electroretinography results suggest a primary rod dysfunction, examination with a FAOSLO demonstrates that cone density is also reduced. This finding may represent an early sign of progression to macular phenotype in FA. The hypoautofluorescence suggests that the albipunctate spots do not represent lipofuscin.
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, New York.
authors.forename: Hongxin
authors.initials: H
authors.lastname: Song
authors.affiliation: Flaum Eye Institute, University of Rochester, Rochester, New York.
authors.forename: Lisa
authors.initials: L
authors.lastname: Latchney
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, New York3The Institute of Optics, University of Rochester, Rochester, New York.
authors.forename: David
authors.initials: D
authors.lastname: Williams
authors.affiliation: Center for Visual Science, University of Rochester, Rochester, New York2Flaum Eye Institute, University of Rochester, Rochester, New York.
authors.forename: Mina
authors.initials: M
authors.lastname: Chung
mesh_terms: D000328:Adult; D002452:Cell Count; D018450:Disease Progression; D004596:Electroretinography; D005260:Female; D005451:Fluorescein Angiography; D005584:Fovea Centralis; D006801:Humans; D019721:Ophthalmoscopes; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology*; D012164:Retinal Diseases / Q000175:diagnosis*; D041623:Tomography, Optical Coherence / Q000379:methods; D014794:Visual Fields