Abstract
Purpose: :
To determine how peripheral visual field (VF) loss in glaucoma and visual acuity (VA) loss in AMD affect physical performance as measured using the Short Physical Performance Battery (SPPB).
Methods: :
Study subjects were recruited from patients age 60 to 80 cared for at Johns Hopkins University. They were recruited from 3 patient groups: glaucoma suspects (controls), glaucoma patients with bilateral VF loss, and AMD patients with bilateral, or severe unilateral, loss of VA. Physical performance was assessed using the SPPB, a measure of lower body functioning highly correlated with future morbidity and mortality. Overall SPPB performance, and performance in each of the 3 test domains (balance, gait speed, and chair stand speed), were analyzed using both univariate and multivariable ordinal logistic regression models.
Results: :
179 subjects completed the study procedures, including 60 control subjects, 84 glaucoma subjects, and 35 AMD subjects. Control subjects’ mean better-eye logMAR VA was 0.08 (SD=0.12), significantly better than both glaucoma subjects’ mean VA of 0.27 (SD=0.37, p<0.001) and AMD subjects’ mean VA of 0.49 (SD=0.37, p<0.001). In univariate models assessing control and glaucoma subjects, a drop of 5 dB in VF MD was associated with a greater likelihood of lower overall SPPB performance (Odds ratio [OR] =1.2, 95% CI=1.0 to 1.5, p=.036), worse balance (OR=1.3, 95% CI=1.1 to 1.6, p=.007), and slower gait (OR=1.3, 95% CI=1.1 to 1.6, p=.016). Univariate models assessing AMD and control subjects demonstrated that a one line drop in VA was associated with a greater likelihood of a lower SPPB performance (OR=1.2, 95% CI=1.0 to 1.3, p=.024), worse balance (OR=1.2, 95% CI=1.0 to 1.3, p=.046), and slower gait (OR=1.2, 95% CI=1.1 to 1.4, p=.006). In multivariable analysis, neither glaucoma nor AMD was associated with a greater likelihood of worse overall SPPB performance, or slower chair stands (all p>.05). AMD subjects, but not subjects with glaucoma were more likely than controls to walk slower at a slower speed (OR = 4.2, 95% CI = 1.4 to 12.5, p=.010). Glaucoma subjects, but not AMD subjects, were more likely than controls to have worse balance (OR=1.3, 95% CI=1.0 to 1.7, p=0.028).
Conclusions: :
Neither visual acuity loss from AMD nor VF loss from glaucoma were associated with global physical performance measures, though slower gait speed was more common in AMD and worse balance was more common in glaucoma. These findings suggest that previous reports noting restriction of physical activity in vision loss are unlikely the result of physical decompensation.