title: A slowly progressive retinopathy in the Shetland Sheepdog.
abstract: OBJECTIVE
  To describe a slowly progressive retinopathy (SPR) in Shetland Sheepdogs. Animals  Forty adult Shetlands Sheepdogs with ophthalmoscopic signs of SPR and six normal Shetland Sheepdogs were included in the study.
  
  
  METHODS
  Ophthalmic examination including slit-lamp biomicroscopy and ophthalmoscopy was performed in all dogs. Electroretinograms and obstacle course-test were performed in 13 affected and 6 normal dogs. The SPR dogs were subdivided into two groups according to their dark-adapted b-wave amplitudes. SPR1-dogs had ophthalmoscopic signs of SPR, but normal dark-adapted b-wave amplitudes. Dogs with both ophthalmoscopic signs and subnormal, dark-adapted b-wave amplitudes were assigned to group SPR2. Eyes from two SPR2 dogs were obtained for microscopic examination.
  
  
  RESULTS
  The ophthalmoscopic changes included bilateral, symmetrical, greyish discoloration in the peripheral tapetal fundus with normal or marginally attenuated vessels. Repeated examination showed that the ophthalmoscopic changes slowly spread across the central parts of the tapetal fundus, but did not progress to obvious neuroretinal thinning presenting as tapetal hyper-reflectivity. The dogs did not appear seriously visually impaired. SPR2 showed significantly reduced b-wave amplitudes throughout dark-adaptation. Microscopy showed thinning of the outer nuclear layer and abnormal appearance of rod and cone outer segments. Testing for the progressive rod-cone degeneration ( prcd )-mutation in three dogs with SPR was negative.
  
  
  CONCLUSIONS
  Slowly progressive retinopathy is a generalized rod-cone degeneration that on ophthalmoscopy looks similar to early stages of progressive retinal atrophy. The ophthalmoscopic findings are slowly progressive without tapetal hyper-reflectivity. Visual impairment is not obvious and the electroretinogram is more subtly altered than in progressive retinal atrophy. The etiology remains unclear. SPR is not caused by the prcd-mutation.
authors: Strömsholm Referral Hospital Strömsholm, Djursjukhusvägen 11 SE-734 94, Strömsholm, Sweden. Lena.Karlstam@telia.com
authors: Lena
authors: L
authors: Karlstam
authors: Eva
authors: E
authors: Hertil
authors: Caroline
authors: C
authors: Zeiss
authors: Ernst Otto
authors: EO
authors: Ropstad
authors: Ellen
authors: E
authors: Bjerkås
authors: Richard R
authors: RR
authors: Dubielzig
authors: Björn
authors: B
authors: Ekesten
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D004283:Dog Diseases / Q000235:genetics* / Q000473:pathology; D004285:Dogs; D005260:Female; D020022:Genetic Predisposition to Disease; D008297:Male; D012164:Retinal Diseases / Q000235:genetics / Q000662:veterinary*