title: Retinal thickness in Parkinson's disease.
abstract: BACKGROUND
  Visual symptoms are common in Parkinson's disease with studies consistently demonstrating reductions in visual acuity, contrast sensitivity, colour and motion perception as well as alterations in electroretinogram latencies and amplitudes. Optical coherence tomography can examine retinal structure non-invasively and retinal thinning has been suggested as a potential biomarker for neurodegeneration in Parkinson's disease. Our aim was to examine the retinal thickness of a cohort of Parkinson's disease subjects (and age-matched controls) to establish the practical utility of optical coherence tomography in a representative older Parkinson's disease group.
  
  
  METHODS
  Fifty-one established Parkinson's disease subjects and 25 healthy controls were subjected to ophthalmological assessment and optical coherence tomography (Zeiss Stratus 3000™) of macular thickness and volume and retinal nerve fibre thickness around the optic nerve head. Twenty four percent of control and 20% of Parkinson's disease subjects were excluded from final analysis due to co-morbid ocular pathology. Further data was excluded either due to poor tolerability of optical coherence tomography or poor quality scans.
  
  
  RESULTS
  Despite a reduction in both visual acuity and contrast sensitivity in the residual evaluable Parkinson's disease cohort, we did not detect any differences between the two study groups for any measures of retinal thickness, in contrast to previously published work.
  
  
  CONCLUSIONS
  In addition to technical problems inherent in the evaluation, the lack of difference between Parkinson's disease and healthy control subjects suggests longitudinal studies, employing newer techniques, will be required to define the role of optical coherence tomography as a potential diagnostic biomarker.
authors: Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, UK. neilarchie@me.com
authors: N K
authors: NK
authors: Archibald
authors: M P
authors: MP
authors: Clarke
authors: U P
authors: UP
authors: Mosimann
authors: D J
authors: DJ
authors: Burn
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D009898:Optic Disk / Q000473:pathology; D010300:Parkinson Disease / Q000473:pathology*; D012160:Retina / Q000473:pathology*; D055351:Retinal Neurons / Q000473:pathology; D041623:Tomography, Optical Coherence