Glaucoma Severity Affects the Location and Rate of Progressing Paracentral Visual Field Points

Abstract

 

Purpose:

 

To evaluate the rate and pattern of initial parafoveal scotoma (IPFS) progression in glaucoma using pointwise linear regression (PLR) analysis of 10-2 visual field (VF) data.

 

Methods:

 

Glaucoma patients with (1) an IPFS in the superior hemifield based on 2 24-2 SITA-Standard VFs (≥3 adjacent points with P<5% within the central 10 degrees (of VF), ≥1 point with P<1% lying at the 4 innermost paracentral points, and no scotoma outside the central 10 degrees) and (2) 5 or more 10-2 VFs were included. PLR analysis was performed using 10-2 pattern deviation map values to calculate the progression rates at all test points, which were averaged to generate the global progression rate of each eye. Significantly progressing points were defined as having a slope worse than -0.5 dB/yr with P<0.01; localized progression rates were defined by the averaged slopes of these points per eye. To create progression rate pattern maps, the eyes were divided into 3 groups by disease severity tertiles, based on 10-2 VF pattern standard deviation (PSD) (Groups A-C, increasing PSD).

 

Results:

 

40 eyes were included (40 patients, mean age, 61±17 yr; mean 24-2 mean deviation, -3.48±0.95 dB; mean follow-up, 5.9±2.1 yr; mean number of 10-2 VFs, 8.1±2.7). The mean global progression rate was -0.25±0.37 dB/yr. For the 20 eyes with ≥1 significantly progressing point, the mean localized progression rate and mean number of progressing points were -2.63±1.49 dB/yr and 4.4±4.5. The mean number of 10-2 VFs (7.6, 7.2, and 9.4; P=0.08) and follow-up periods (5.7, 6.0, and 6.1 yrs; P=0.86) were similar between the 3 PSD groups. After controlling for mean follow-up IOP, age, and central corneal thickness, VF progression rates decreased as the disease advanced (all P<0.05; Figure). The points progressing fastest at the earliest stage (Group A) were present near fixation in an arcuate pattern. As the disease advanced (Groups B & C), locations of the fastest progressing points shifted toward the nasal periphery and spared the papillomacular bundle (Figure).

 

Conclusions:

 

Based on PLR analysis, progressing points in the paracentral region shift peripherally as glaucoma advances and do not typically involve the papillomacular bundle. Eyes with IPFS, even at its early stages, should be monitored closely for progression.  

 

Keywords: perimetry • visual fields • clinical (human) or epidemiologic studies: outcomes/complications