Central Visual Field Defects in Early Glaucoma May Indicate Stereoacuity Loss

Central visual field defects in patients with early to moderate glaucoma may serve as a biomarker for stereoacuity loss, according to an investigation published in Ophthalmology Glaucoma.

Researchers from the Glaucoma Research Center at Wills Eye Hospital enrolled 65 patients (mean age, 64.3 years; 64.6% women) with early to moderate glaucoma with a mean deviation (MD) better than -12 dB and a visual acuity of 20/40 or better in the prospective, longitudinal, observational cohort study. The team evaluated stereoacuity and central visual field defects, and assessed vision-related quality of life (VR-QOL) using the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25). A significant defect in any of the central 4 points of the 24-2 visual field standard total deviation map constituted a central visual field defect.

Overall, 42 patients had these defects compared with 23 who did not (65% vs 35%). Individuals with central visual field defects had poorer visual field mean deviation in the better (mean, -3.3 vs -2 dB; P =.022) and worse-seeing eye (mean, -7.1 vs -3.6 dB; P <.001), visual field index in the worse-seeing eye (mean, 82.6 vs 93.5; P <.001), and contrast sensitivity in the worse-seeing eye (mean, 1.21 vs 1.29; P =.040) compared with individuals without defects.

A majority of individuals with central visual field defects (71.4%) had reduced stereopsis, while individuals without the defects (60.9%) often demonstrated normal stereopsis. A total of 7.1% of individuals with defects had absent stereopsis.

Univariate analysis revealed that stereopsis grade was associated with central visual field defects, worse-seeing eye contrast sensitivity, and worse-seeing eye visual field mean deviation, but only central visual field defects predicted stereopsis level in the multivariate analysis (odds ratio [OR], 4.49; 95% CI, 1.25-16.07; P =.021).

Study participants with defects reported lower VFQ-25 scores for near activities (mean, 78.6 vs 93.4; P =.001), general vision (mean, 73.0 vs 85.2; P =.002), mental health (mean, 77.5 vs 88.9; P =.007) and composite scores (mean, 84.0 vs 91.4; P =.004) compared with individuals without the defects, respectively.

“Our results suggest that these patients with [central visual field defects] are more likely to have reduced stereopsis, even at early stages of the disease, and supports the need to counsel patients as to how decreased depth perception may contribute to difficulties in performing daily activities and increased fall risk,” according to the study authors.

The exclusion of individuals with advanced stage defects is an acknowledged study limitation.