title: Screening for CMV retinitis using chromatic discrimination thresholds and achromatic contrast sensitivity.
abstract: BACKGROUND
  Many patients with cytomegalovirus retinitis (CMVR) are unaware of visual disturbance so screening is advocated for patients with HIV and low CD4 counts. Many tests of retinal function have been recommended but few are effective at detecting CMVR. We assess the potential of chromatic discrimination thresholds and achromatic contrast sensitivity as screening tests for patients with CMVR.
  
  
  METHODS
  11 HIV+ patients with CMVR, 16 age matched HIV+ patients, and 29 age matched controls were recruited. Visual acuity, chromatic discrimination thresholds, and achromatic contrast sensitivity were measured. Fundal examination was performed by slit lamp biomicroscopy for HIV+ patients. Those with CMVR were photographed and the CMVR graded from the photographs.
  
  
  RESULTS
  Loss of chromatic discrimination was found in patients with CMVR (tritan p<0.0005, red/green p<0.05). The same group had deterioration in achromatic contrast sensitivity at 2.2, 3.4, and 10 cpd (p<0.05). There was correlation between the zone of CMVR with chromatic gratings (tritan r=0.83, p<0.005). No statistically significant difference was found between the HIV+ patients and the controls for all tests (p>0.1).
  
  
  CONCLUSIONS
  HIV+ patients with CMVR have a loss of chromatic discrimination and achromatic contrast sensitivity and this may be used to screen HIV+ patients for CMVR.
authors.affiliation: Sussex Eye Hospital, Brighton. rbnewsom@dircon.co.uk
authors.forename: R S
authors.initials: RS
authors.lastname: Newsom
authors.forename: G L
authors.initials: GL
authors.lastname: Ong
authors.forename: T L
authors.initials: TL
authors.lastname: Jackson
authors.forename: I
authors.initials: I
authors.lastname: Coldrick
authors.forename: L G
authors.initials: LG
authors.lastname: Ripley
authors.forename: M
authors.initials: M
authors.lastname: Fisher
authors.forename: A G
authors.initials: AG
authors.lastname: Casswell
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000150:complications; D000328:Adult; D016022:Case-Control Studies; D003118:Color Perception / Q000502:physiology*; D003117:Color Vision Defects / Q000150:complications / Q000175:diagnosis; D015350:Contrast Sensitivity / Q000502:physiology*; D017726:Cytomegalovirus Retinitis / Q000150:complications / Q000175:diagnosis*; D015658:HIV Infections / Q000150:complications; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D014792:Visual Acuity / Q000502:physiology*