Purpose
To determine the suitability of frequency doubling perimetry (FDT) for glaucoma monitoring.
Methods
One hundred twenty six eyes of 126 glaucoma patients were included. Patients were followed prospectively with the Humphrey Field Analyzer (HFA; 30-2 SITA) and FDT (C20-1 full threshold) in the Groningen Longitudinal Glaucoma Study, an observational cohort study. The rate of progression (ROP) was calculated. We used the mean deviation (MD) for HFA and the number of test locations with p < 1% in the total deviation probability plot for FDT. Patients were stratified in three equally sized groups (tertiles; slow, average and fast progressors) based on their ROP, for both HFA and FDT.
Results
On average 8.1 HFA and 4.5 FDT tests were available after a mean follow-up (identical for HFA and FDT) of 6.4 years. The mean (SD) HFA MD at baseline was -7.9 (6.4) dB; the mean (SD) number of abnormal FDT test locations at baseline was 6.1 (4.5). The mean (SD) HFA ROP was -0.28 (0.55) dB/yr and the mean (SD) FDT ROP was 0.12 (0.50) abnormal test locations per year. There was a highly significant association between HFA and FDT ROP (chi-squared test: p<0.001; see figure).
Conclusions
Using frequency doubling perimetry for the monitoring of glaucoma patients can give some insight in disease progression. This suggests that FDT can be used in patients who cannot be reliably tested with standard automated perimetry.
Keywords: 642 perimetry •
758 visual fields