Prediction of visual field defects on standard automated perimetry by screening C-20-1 frequency doubling technology perimetry.

PURPOSE: To determine if perimetric defects, initially seen with C-20-1 frequency doubling technology (FDT) in eyes with normal standard automated perimetry (SAP), will subsequently develop on standard automated perimetry.
METHODS: Review of patients considered high-risk glaucoma suspects (GS) or with ocular hypertension (OHT), who underwent one C-20-1 FDT in 1997 or 1998. An abnormal frequency doubling technology was defined in two ways, as having either at least one, or at least two abnormal locations. An abnormal standard automated perimetry was defined as fulfilling two of three modified Anderson criteria for abnormality on two consecutive tests and at final standard automated perimetry.
RESULTS: Of 63 eyes (50 patients), 18 (28.6%) had >or=1 FDT defects, and 12 (19.0%) had >or=2 defects. After follow-up of 62 +/- 26 months, an abnormal standard automated perimetry developed in 5 eyes (28%) with frequency doubling technology defects at 22 +/- 13 months (28% of eyes with >or=1 defect and 42% of eyes with >or=2 FDT defects), and in 4 of 45 eyes (9%) with normal frequency doubling technology at 32 +/- 30 months. Kaplan-Meier survival analysis revealed the risk of an abnormal standard automated perimetry at 5 years with <or=1 FDT defect, no defects, >or=1 defects, and >or=2 defects, was 10.3%, 11.8%, 30.6%, and 46.4% respectively (P = 0.060 for >or=1 defects compared with no defects; P = 0.002 for >or=2 defects compared with <or=1 defect).
CONCLUSIONS: Abnormal results on C-20-1 frequency doubling technology perimetry predicted glaucomatous visual field loss on standard automated perimetry in some patients in this patient population, though a relatively high false positive rate was noted. Abnormality on C-20-1 frequency doubling technology warrants close observation, and further prospective evaluation is warranted.