Abstract
Purpose :
Stereopsis is a binocular phenomenon dependent on higher order visual processing. We previously reported that although stereopsis can reliably suggest a range of visual acuity (VA) in patients with no history of strabismus1, it cannot be used to establish a given VA. Michael Brodsky, M.D.2 suggested that reverse stereovision testing in patients with bitemporal hemianopias demonstrates absence of stereopsis. The goal of this study was to compare the results of stereopsis and reverse stereopsis in patients without visual field (VF) defects before testing Dr. Brodsky’s hypothesis.
Methods :
Patients seen in a neuro-ophthalmic service over a 6 month period underwent a detailed examination, including polarized vectogram stereoacuity measurements (Titmus) and VF. Patients were first tested with the stereoacuity book upright (traditional stereoacuity, “TS”) and then with the stereoacuity book rotated 180 degrees (reverse stereoacuity, “RS”).
Results :
Of 495 patients tested, we included the 98 (median age, 45 years [13-79]) who had normal VF, no ocular misalignment, and >0 circles on TS. Among these 98 patients mean score was 7.8/9 circles correct on TS and 7.5/9 on RS [p-value 0.07, paired two-tailed t-test]. 26/98 patients (26.5%) scored higher on TS than on RS (average difference, 2.3 circles), 16 patients (16.3%) scored higher on RS than on TS (average difference, 2.0 circles), and 56 patients (57.1%) scored the same on both. 64/98 patients (65.3%) scored 9/9 circles correct on TS; of those 64, 54 (84.4%) scored 8/9 or 9/9 circles, 5 (7.8%) scored 7/9 circles, 2 scored 6/9, and 1 patient each scored 5/9, 3/9, and 2/9 on RS.
Conclusions :
In a patient population presenting for neuro-ophthalmology evaluation with normal VF and without strabismus, there is no difference in TS and RS testing. Therefore, any difference found in patients with homonymous or heteronymous VF defects may relate to the VF defect itself.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.