title: Macular cone abnormalities in retinitis pigmentosa with preserved central vision using adaptive optics scanning laser ophthalmoscopy.
abstract: OBJECTIVE
  To assess macular photoreceptor abnormalities in eyes with retinitis pigmentosa (RP) with preserved central vision using adaptive optics scanning laser ophthalmoscopy (AO-SLO).
  
  
  METHODS
  Fourteen eyes of 14 patients with RP (best-corrected visual acuity 20/20 or better) and 12 eyes of 12 volunteers underwent a full ophthalmologic examination, fundus autofluorescence, spectral-domain optical coherence tomography (SD-OCT), and imaging with a prototype AO-SLO system. Cone density and spatial organization of the cone mosaic were assessed using AO-SLO images.
  
  
  RESULTS
  In 3 eyes with RP and preserved central vision, cones formed a mostly regular mosaic pattern with small patchy dark areas, and in 10 eyes, the cone mosaic patterns were less regular, and large dark regions with missing cones were apparent. Only one eye with RP demonstrated a normal, regular cone mosaic pattern. In eyes with RP, cone density was significantly lower at 0.5 mm and 1.0 mm from the center of the fovea compared to normal eyes (P<0.001 and 0.021, respectively). At 0.5 mm and 1.0 mm from the center of the fovea, a decreased number of cones had 6 neighbors in eyes with RP (P = 0.002 for both). Greater decrease in cone density was related to disruption of the photoreceptor inner segment (IS) ellipsoid band on SD-OCT images (P = 0.044); however, dark regions were seen on AO-SLO even in areas of continuous IS ellipsoid on SD-OCT. Decreased cone density correlated thinner outer nuclear layer (P = 0.029) and thinner inner segment and outer segment thickness (P = 0.011) on SD-OCT.
  
  
  CONCLUSIONS
  Cone density is decreased and the regularity of the cone mosaic spatial arrangement is disrupted in eyes with RP, even when visual acuity and foveal sensitivity are good. AO-SLO imaging is a sensitive quantitative tool for detecting photoreceptor abnormalities in eyes with RP.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Kyoto, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Makiyama
authors.forename: Sotaro
authors.initials: S
authors.lastname: Ooto
authors.forename: Masanori
authors.initials: M
authors.lastname: Hangai
authors.forename: Kohei
authors.initials: K
authors.lastname: Takayama
authors.forename: Akihito
authors.initials: A
authors.lastname: Uji
authors.forename: Akio
authors.initials: A
authors.lastname: Oishi
authors.forename: Ken
authors.initials: K
authors.lastname: Ogino
authors.forename: Satoko
authors.initials: S
authors.lastname: Nakagawa
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009887:Ophthalmoscopy / Q000379:methods*; D011446:Prospective Studies; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology; D012174:Retinitis Pigmentosa / Q000175:diagnosis* / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult