Progression Pattern of Initial Parafoveal Scotomas in Glaucoma

Abstract

To characterize the progression pattern of initial parafoveal scotomas (IPFSs) using cross-sectional and longitudinal 10-2 visual field (VF) data. Retrospective, observational study. Glaucoma patients with an IPFS in either hemifield based on 2 reliable 24-2 Swedish interactive threshold algorithm standard VFs (≥3 adjacent points with P<0.05 within the central 10° of fixation, 1 point or more with P<0.01 lying at the innermost paracentral points, and no scotoma outside the central 10°) and at least 2 10-2 VFs (first and last VFs 1 year or more apart). To simulate a cohort with an extended follow-up, eyes with an IPFS were divided into subgroups based on the severity of glaucoma using their 10-2 VF pattern standard deviation (PSD). Cross-sectional data were used to create an average pattern deviation map that was generated by averaging pattern deviation map values of 10-2 VF point-by-point within each subgroup. Longitudinal data (eyes with 5 or more 10-2 VFs) was used to perform pointwise linear regression analysis of pattern deviation values. Patterns of IPFS progression were identified from these cross-sectional and longitudinal assessments. Average pattern deviation maps (cross-sectional) and maps of progression rates (longitudinal) in different disease severity subgroups. Eighty eyes (80 patients) and 40 eyes (40 patients) with an IPFS were included for cross-sectional and longitudinal analyses, respectively. The mean age ± standard deviation, 24-2 VF mean deviation, and 24-2 VF PSD for all eyes were 63±10 years, -3.27±2.18 dB, and 5.46±2.40 dB, respectively. Based on maps generated in both cross-sectional and longitudinal analyses, IPFS in the superior hemifield had an arcuate pattern initially that later deepened approximately 3° to 5° above fixation. The scotoma then elongated toward the physiologic blind spot and spread toward the nasal periphery, sparing the area corresponding to the papillomacular bundle. The IPFS in the inferior hemifield had a similar pattern, but was slightly farther from fixation. Superior and inferior IPFS have a similar characteristic pattern of progression, although the latter tend to be farther from fixation. Understanding these patterns should help in the management of such patients and in improving VF testing algorithms.