Abstract
Purpose::
To estimate the rate of worsening of visual field damage among open angle glaucoma (OAG) subjects from three cross-sectional studies.
Methods::
OAG subjects from the Baltimore Eye Survey (BES), the Salisbury Eye Evaluation (SEE), and Proyecto VER were chosen based on Foster’s definition: a vertical cup to disc ratio of 0.7 or higher and an abnormal visual field test by standard criteria. Our measure of OAG damage was mean deviation (MD) of the Zeiss-Meditec HFA automated field test in the worse eye. For each subject, MD was divided by the age- and race-specific average duration of OAG which was estimated from OAG incidence and actuarial mortality using a life-table approach. Age-specific OAG incidence was estimated from age-specific OAG prevalence (Leske 1981; Quigley 2006). Standard errors were estimated by bootstrapping.
Results::
There were 94 white, 135 black, and 94 Hispanic OAG subjects (age range, 40 to 94 years) from the BES, SEE, and Proyecto VER studies. Average MD in the worse eye was -11.0 dB (SD = 7.5) in whites, -12.3 dB (SD=8.9) in blacks, and -12.1 dB (SD=9.5) in Hispanics. We estimated an overall individual rate of progression of -0.88 dB/year (SE=0.04) across all 3 races; -0.76 dB/year (SE = 0.06) in whites, -0.82 dB/year (SE=0.05) in blacks, and -1.06 dB/year (SE=0.09) in Hispanics. Estimated individual progression rates did not differ by gender. Estimated progression was worse among those who received glaucoma treatment; this was most likely because those with worse glaucoma damage sought treatment.
Conclusions::
Calculated OAG progression rates are similar to progression estimates for untreated OAG subjects in clinical trials (CNGTS, EMGT). The progression rate in Hispanics was higher than rates in whites and blacks. These estimates can aid public health planning and serve as benchmarks for other progression studies.
Keywords: aging: visual performance • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • visual fields