Correlation Between Visual Acuity and Automated Visual Field Foveal Threshold.

Background: Previous studies have determined a signficant correlation between, foveal threshold on automated visual field perimetry and best-corrected visual acuity. To our knowledge, these correlations have not been studied using the Octopus (Haag-Streit, Köniz, Switzerland) perimeter.

Methods: Patients underwent Octopus automated visual field testing using the glaucoma tendency-oriented perimetry protocol where a foveal threshold value was collected. Visual acuity was determined in the patient's current refractive glasses and/or with pinhole acuity. Visual acuity was converted from Snellen to logarithm of the minimum angle of resolution (logMAR) for statistical analysis. Spearman correlation coefficient was used to determine correlation between visual acuity and foveal threshold value.

Results: A total of 332 eyes (243 diseased eyes and 89 healthy eyes) were assessed. A statistically significant negative correlation was found between visual acuity and foveal threshold (P < 0.001). The estimated foveal threshold was statistically significantly decreased by 1.2 dB per every 0.1 logMAR increase of visual acuity (P < 0.001). A foveal threshold of 27.47 or higher predicted a visual acuity of 20/40 or better with 90% confidence.

Conclusions: Patient best-corrected logMAR visual acuity has a negative correlation with foveal threshold in automated (Octopus) visual field testing. Our findings suggest that foveal threshold may predict measured visual acuity. We created a website application to predict visual acuity based on foveal threshold, age, and presence or absence of ocular pathology. Foveal threshold may represent a surrogate estimate of acuity for patients who are unable to read the Snellen chart and for patients with functional vision loss.