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Improved stereoacuity: an indication for unilateral cataract surgery
B R Kwapiszeski1, C C Gallagher, J M Holmes
1Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota 55905, USA.
Purpose:
To determine whether stereoacuity is an objective indicator of functional improvement following unilateral cataract surgery.
Setting:
Department of Opthalmology, Loyola University Chicago, Maywood, Illinois.
Methods:
Seventeen consecutive patients with unilateral cataracts (8 pseudophakic, 9 phakic in contralateral eye) were studied prospectively. Best corrected distance visual acuity in the eye with cataract ranged from 20/40 to 20/400. Distance acuity in the eye without cataract was 20/20 or 20/25. All patients had cataract surgery with posterior chamber intraocular lens implantation. Stereoacuity was measured preoperatively and postoperatively; at near by Titmus test (TT) and at distance by B-VAT BVS random dot E (BVRDE) and contour circles (BVC). Nonparametric Spearman rank correlation and Wilcoxon rank tests were used for analysis.
Results:
Preoperatively, reduced near visual acuity in the cataractous eye correlated with reduced near stereo (TT), r = .6, P = .01. Postoperatively, near stereoacuity improved in all but one patient, from a median of 200 seconds of arc (sec arc) to 40 sec arc (P = .004); distance stereoacuity improved in all but two patients from a median of unrecordable to 120 sec arc (BVC) (P = .006). Preoperatively none of the patients could see the largest distance BVRDE target, whereas postoperatively 4 of 17 had BVRDE stereoacuity of 120 to 240 sec arc (P = .06).
Conclusions:
Patients with unilateral cataracts have reduced stereoacuity, correlating with their reduced monocular visual acuity. In this study, distance and near stereoacuity improved postoperatively. Decreased stereoacuity may provide an indication for unilateral cataract surgery.