title: Impact of diabetes on glaucoma screening using frequency-doubling perimetry.
abstract: OBJECTIVE
  To determine whether diabetes is a potential source of abnormal test results in glaucoma screening by use of frequency-doubling perimetry.
  
  
  METHODS
  Observational case series.
  
  
  METHODS
  Twenty-five patients with diabetes and 25 nondiabetic normal controls, all without cataract or glaucoma.
  
  
  METHODS
  Frequency-doubling perimetry using the C-20-5 screening mode was performed in 1 randomly selected eye of each participant. Abnormal test results were immediately repeated to reduce artifacts caused by test inexperience. Frequency-doubling technology (FDT) results were assigned a numerical score between 0 (normal) and 87 (no stimuli detected).
  
  
  METHODS
  Abnormal FDT test scores.
  
  
  RESULTS
  Overall, 7 of 25 (28%) patients with diabetes and 1 of 25 (4%) normal controls had an abnormal test; the 1 normal subject with an abnormal test was subsequently determined to have an abnormal glucose tolerance test. Four of the 7 patients with diabetes with abnormal FDT tests had no evidence of diabetic retinopathy on clinical examination. Patients with diabetes had higher test scores than normal controls (8.9+/-16.9 vs. 1.0+/-4.4, P = 0.028) and had longer test times than normal controls (66.4+/-35.5 seconds vs. 48.3+/-11.2 seconds, P = 0.019).
  
  
  CONCLUSIONS
  Frequency-doubling perimetry is abnormal in some patients with diabetes, including some patients with diabetes without clinical evidence of diabetic retinopathy. Abnormal FDT testing in diabetic eyes may not represent glaucomatous visual field loss. Diabetes may be a source of "false-positive" test results when this technology is used for glaucoma screening.
authors.affiliation: Department of Ophthalmology, West Virginia University Eye Institute, Morgantown, West Virginia 26506, USA. realinia@rcbhsc.wvu.edu
authors.forename: Tony
authors.initials: T
authors.lastname: Realini
authors.forename: Michelle Q
authors.initials: MQ
authors.lastname: Lai
authors.forename: Laurie
authors.initials: L
authors.lastname: Barber
mesh_terms: D000328:Adult; D000368:Aged; D048909:Diabetes Complications / Q000175:diagnosis*; D003930:Diabetic Retinopathy / Q000175:diagnosis; D005189:False Positive Reactions; D005260:Female; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D014786:Vision Disorders / Q000175:diagnosis*; D015351:Vision Screening / Q000379:methods*; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields