Postoperative Stereopsis in Adult Patients With Horizontal Comitant Strabismus With Normal Vision Who Are Stereoblind

Purpose: To examine stereopsis in patients with comitant horizontal strabismus who had normal vision and were stereoblind following the strabismus surgery. Methods: Twenty patients with primary comitant horizontal strabismus and normal corrected visual acuity were included in this study. The stereoacuity was quantitatively measured by the random dot butterfly stereotest, the Randot Preschool Stereoacuity Test (Stereo Optical, Inc., Chicago, IL), and synoptophore. Results: Twenty patients with comitant strabismus (14 exotropia and 6 esotropia) with normal corrected visual acuity but without stereopsis were included. The average prism deviation was 63.55 +/- 18.52 prism diopters (PD) (range: 30 to 90 PD). The mean duration of strabismus was 17.93 +/- 7.0 years (range: 5 to 30 years). At 3 days postoperatively, 22.2% (4 of 18) of the patients had improved stereopsis and the mean stereoacuity was 60 +/- 28.28 seconds of arc by random dot butterfly stereotest and 150 +/- 57.74 seconds of arc by Randot Preschool Stereoacuity Test (P < .05). For the fusion and stereopsis at far measured by the synoptophore, 11.1% (2 of 18) of the patients demonstrated recovery of fusion and substantial recovery of stereopsis. The mean stereoacuity (at far) was 200 seconds of arc. At the last follow-up visit (3 to 12 months, average 6.55 +/- 3.46 months), 45% (9 of 20) of the patients demonstrated substantial near stereopsis recovery and the median stereoacuity was 53.33 +/- 33.17 seconds of arc by random dot butterfly stereotest and 95.56 +/- 63.07 seconds of arc by the Randot Preschool Stereoacuity Test (P < .01). A total of 25% (5 of 20) of the patients demonstrated recovery of fusion and 15% (3 of 20) of the patients showed substantial recovery of stereopsis at far. The median stereoacuity (at far) was 193.33 +/- 179.26 seconds of arc. Conclusions: The results demonstrated that adult patients with comitant strabismus who had good vision and were stereoblind benefited from strabismus surgery and the stereopsis improved. Near stereopsis was easier to regain than far stereopsis.