Purpose
To determine the rate of glaucomatous visual field change in > 2,000 patients followed clinically in a tertiary eye care centre.
Methods
All patients with glaucoma or suspected glaucoma, with ≥ 5 standard automated perimetry exams (24-2 SITA) and ≥ 2 years follow-up were included in the analysis. Rates of Mean Deviation (MD) change were derived in one randomly selected eye with robust linear regression analysis. The proportion of patients with “fast” (worse than -1 dB/yr) and “catastrophic” (worse than -2 dB/yr) progression was computed as well as the relationship between baseline MD and baseline age on MD rate. To determine whether MD rate statistics depended on the number of exams, the sample was divided into quintiles based on an approximately equal number of exams to ensure the MD rate statistics were independent.
Results
There were 2,198 patients in this study with a median (interquartile range, IQR) baseline age of 65.7 (57.0, 74.0) years, baseline MD of -2.4 (-5.3, -0.84) dB and follow-up of 7.2 (4.9, 10.2) years with 8 (6, 11) exams. The mean (SD) and median (IQR) MD rates were -0.16 (0.63) dB/yr and -0.06 (-0.31, 0.11) dB/yr respectively. There were 124 (5.6%) patients with fast and 33 (1.5%) patients with catastrophic progression (Figure). Baseline MD correlated poorly with MD rate (r = -0.23, P = 0.27), however, advancing baseline age was statistically significantly associated with a worse MD rate (r = -0.20, P < 0.01). MD rate statistics depended on the number of examinations, with the proportion of fast progressors varying from 2.4 to 9.2% and catastrophic progressors from 0.2 to 3.9% (Table). The median MD rate worsened with an increasing number of exams.
Conclusions
(1) There was a significantly stronger association between advancing age and worse MD rate compared to that between baseline MD and MD rate; (2) MD rate statistics are influenced by the number of exams, with a lower exam frequency yielding a higher proportion of patients with faster progression.
Keywords: 758 visual fields •
462 clinical (human) or epidemiologic studies: outcomes/complications •
642 perimetry