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

Abstract

Purpose To compare the ability of frequencydoubling 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 À2.3 ± 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, P 0.42-0.71) were as follows: number of locations in the pattern deviation probability (PDP) plot with Po5% 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 (Po0.002). 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.

Frequency doubling technology, optical coherence technology and pattern electroretinogram in ocular hypertension

“…Histopathological experimental studies of optic nerve in glaucoma patients suggest an early and selective impairment of M-cells [35,36]. The percentage of our OH eyes with abnormal FDT results is comparable with other studies [26,37-40], but this elevated percentage could be partially due to false positive results.…”

Frequency doubling technology, optical coherence technology and pattern electroretinogram in ocular hypertension

“…Histopathological experimental studies of optic nerve in glaucoma patients suggest an early and selective impairment of M-cells [35,36]. The percentage of our OH eyes with abnormal FDT results is comparable with other studies [26,[37][38][39][40], but this elevated percentage could be partially due to false positive results.…”

‘Structure–function relationship’ in glaucoma: past thinking and current concepts

“…Consequently, correlations between sensitivity and ganglion cell density are typically higher than correlations reported between sensitivity and structural surrogates of ganglion cell density made in clinical studies. Harwerth et al 's study has often been incorrectly cited as supporting the idea that structure precedes function 43–48 …”

“…Harwerth et al's study has often been incorrectly cited as supporting the idea that structure precedes function. [43][44][45][46][47][48] Data from large clinical trials illustrate that perimetric damage can precede ONH changes in 35% to 86% of patients, Figure 4. In the Ocular Hypertension Treatment Study, a visual field end-point was reached first in 35% of patients (structural change in 55%) 3,49 whereas this figure was 60% and 86% for the European Glaucoma Prevention Study and Early Manifest Glaucoma Trial, respectively.…”