Objective: To investigate the diagnosis value of the frequency doubling perimetry (FDP) screening program in the aged 40 or more natural population-based glaucoma screening.
Methods: In 3 natural villages of Daxing District and 4 northern metropolitan communities of Beijing, 4439 subjects aged 40 or over were screened for glaucoma from May to October in 2001. The screening protocol C-20-1 of the frequency doubling perimetry (FDP) was used in all subjects. For suspect glaucoma subjects, TOP threshold visual field testing with an Octopus perimeter, gonioscopy and stereo fundusgraphy were performed on different days. Detected Glaucoma patients were classified as mild (MD 5 dB or less), moderate (MD > 5 dB and < 10 dB) and advanced (MD 10 dB or more) degrees according to their Octopus test results. FDP parameters including test time, numbers of abnormal location, comtotalon score and score by quadrant were analyzed. Data from one eye of normal subjects and milder eye of optic nerve damage in glaucoma subjects were analyzed.
Results: After excluding subjects whose fixation error or false positive error was > 0.33, data from 4330 subjects (97.54%) were analyzed. If abnormality of one location or more was used as a FDP cutoff, and subjects were divided into normal and glaucoma two groups (excluded other eye diseases in non-glaucoma subjects); the FDP had a sensitivity of 50.70% (72/142), a specificity of 90.58% (2260/2340), an area under the ROC curve (AUC) of 0.74, a positive predictive value (PV) of 47.71%, a negative predictive value of 96.95%, a positive likelihood ratio (LR) of 14.83 and a negative LR of 0.51. If excluded the eyes without glaucomatous optic nerve changes and visual field damage, the FDP had a sensitivity of 76.39%, an AUC of 0.87, a positive PV of 40.74%, a negative PV of 99.25%, a positive LR of 22.34 and a negative LR of 0.24. The sensitivity of detecting mild, moderate and advanced glaucoma was 54.17%, 76.00% and 100.00%, respectively. There was strong negative correlation between FDP quadrant score and quadrant mean sensitivity (MS) of Octopus perimetry in glaucoma patients (Spearman correlation, Rs = -0.732, -0.628, -0.639, -0.679, all P = 0.000).
Conclusions: The FDP screening protocol C-20-1 is a very rapid functional test for screening glaucoma in large natural populations aged 40 or more and is proven to be feasible. It has high specificity and good sensitivity for moderate and advanced glaucoma.