A novel distribution of visual field test points to improve the correlation between structure-function measurements

Abstract

Purpose. To create a new visual field (VF) test grid centered at the optic disc (disc-centered field [DCF]) and to infer the combination of VF test points (structure-function field [SFF]), taken from the DCF and the conventional fovea-centered 24-2 grid (24-2) of standard automated perimetry, which yields the strongest sectorial correlation between structure-function measurements of retinal nerve fiber layer (RNFL) thickness and VF sensitivity. Methods. In 50 eyes with ocular hypertension or open angle glaucoma, the DCF and 24-2 VF were measured with a Humphrey Field Analyzer II (Full Threshold strategy) and RNFL thickness was measured with Stratus optical coherence tomography. Test points from the DCF and 24-2 VF were combined and divided into 12 sectors according to the spatial distribution of the RNFL. A novel VF for structure-function studies was established using the following criteria: each sector must contain at least one or two test points (depending on the sector's location), and the combination of test points which yields the strongest structure-function correlation is selected. Results. The SFF consisted of 40 test points. The structure-function correlation for the SFF was compared with the standard 24-2 VF; a multiple-comparison test for dependent groups was carried out using a percentile bootstrap method, which indicated that the sector correlation coefficients in the SFF were significantly higher than those in the 24-2 VF. Conclusions. The SFF, with fewer test locations, has a stronger structure-function correlation than the 24-2 VF. This improved correlation may help clinicians to better interpret functional measurements in relation to structural measurements. © 2012 The Association for Research in Vision and Ophthalmology, Inc.