Non-conventional perimetric methods in the detection of early glaucomatous functional damage

PURPOSE

To compare the ability of frequency-doubling technology (FDT), rarebit perimetry (RBP), and pulsar perimetry (PP) in detecting early glaucomatous functional damage.

METHODS

This prospective observational cross-sectional case study included 52 patients with early primary open-angle glaucoma (mean deviation -2.3+/-1.1 dB; pattern standard deviation 3.0+/-1.2 dB) and 53 healthy controls. Visual field (VF) testing included standard automated perimetry (SAP) Humphrey Field Analyzer 30-2, FDT N-30, RBP (version 4.0), and PP T30W. One eye per patient was considered. Sensitivity at fixed specificities and area under the receiver operating characteristic curve (AROC) for discriminating between healthy and glaucomatous eyes were calculated and compared.

RESULTS

The parameters associated with the largest AROC, which were not statistically different (Hanley-McNeil method, P0.42-0.71) were as follows: number of locations in the pattern deviation probability (PDP) plot with P<5% for FDT (0.93); mean hit rate for RBP (0.95); and mean defect for PP (0.94). PP test duration was significantly shorter than FDT and RBP (P<0.002).

CONCLUSIONS

FDT, PP, and RBP are useful non-conventional VF methods in detecting early glaucomatous VF defects with similar AROCs. The methods were rapid and easy, and PP took less than half the time than SAP. These non-conventional testing may prove to be useful in providing additional information in the diagnosis of glaucoma suspect with normal SAP results, in the therapeutic decision-making process of early glaucomatous patients, and in subjects unable to perform VF testing with SAP.