title: Inverse pattern of photoreceptor abnormalities in retinitis pigmentosa and cone-rod dystrophy.
abstract: OBJECTIVE
  To determine the characteristics of the photoreceptor abnormalities in retinitis pigmentosa (RP) and cone-rod dystrophy (CRD).
  
  
  METHODS
  We evaluated the photoreceptor abnormalities using spectral-domain optical coherence tomography (SD-OCT) in 28 patients with RP and 17 patients with CRD. The OCT images and full-field electroretinograms were obtained from 21 eyes in normal subjects who were age-matched to patients with RP and CRD and served as controls.
  
  
  RESULTS
  Eyes with RP and CRD had markedly decreased rod responses (6.5 and 57.5 % of normal value), maximal responses (9.6 and 51.6 %), cone (16.5 and 25.8 %), and 30-Hz flicker responses (17.8 and 30.1 % of normal value), and their P values were smaller than 0.0003. On comparison of ERG data between RP and CRD, they had statistically significant differences in rod responses (P < 0.0003) and maximal responses (P < 0.0003). However, there were no statistical differences in cone response and a weak difference in 30-Hz flicker responses (P < 0.017). The best-corrected visual acuity was -0.03 ± 0.09 (logMAR, mean ± standard deviation [SD]) in eyes with RP, but 0.57 ± 0.54 in eyes with CRD. SD-OCT showed that eyes with RP had an intact reflective line at the junction between the photoreceptor inner and outer segment (IS/OS) at the fovea, while eyes with CRD had no IS/OS. The extent of the central visual field was correlated with the IS/OS length at the macula in eyes with RP.
  
  
  CONCLUSIONS
  The distribution patterns of the IS/OS line help to differentiate between RP and CRD.
authors.affiliation: Department of Ophthalmology, Gunma University School of Medicine, 3-39-22 Showamachi, Maebashi, 371-8511, Japan. ykcmdr@yahoo.co.jp
authors.forename: Midori
authors.initials: M
authors.lastname: Yokochi
authors.affiliation: Department of Ophthalmology, Gunma University School of Medicine, 3-39-22 Showamachi, Maebashi, 371-8511, Japan.
authors.forename: Danjie
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Ophthalmology, Fujita Health University School of Medicine, Aichi, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Horiguchi
authors.affiliation: Department of Ophthalmology, Gunma University School of Medicine, 3-39-22 Showamachi, Maebashi, 371-8511, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Kishi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004596:Electroretinography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology / Q000502:physiology*; D055211:Retinal Photoreceptor Cell Inner Segment / Q000473:pathology; D055214:Retinal Photoreceptor Cell Outer Segment / Q000473:pathology; D017948:Retinal Rod Photoreceptor Cells / Q000473:pathology / Q000502:physiology*; D012174:Retinitis Pigmentosa / Q000503:physiopathology*; D041623:Tomography, Optical Coherence / Q000379:methods; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology