A prospective study of binocular visual function before and after successful surgery to remove a unilateral epiretinal membrane.
OBJECTIVE
To examine the effect of a unilateral epiretinal membrane (uERM) on visual acuity, stereopsis, and motor fusion in patients before and after successful surgery to remove the membrane.


METHODS
Cohort study.


METHODS
Twenty-seven consecutive patients undergoing surgery to remove an idiopathic uERM and 30 normal control subjects.


METHODS
Patients underwent full orthoptic examination before and between 3 and 6 months after surgery to remove a uERM. Stereoacuities were analyzed statistically using the Wilcoxon signed-rank test, Mann-Whitney U test, and Spearman correlation. Motor fusion ranges and visual acuities were compared using paired and unpaired t tests, with correlations examined by linear regression.


METHODS
Snellen visual acuity, TNO (stereoscopic acuity test of the Netherlands; Netherlands Organisation for Applied Scientific Research; Laméris Ootech BV, Nieuwegein, the Netherlands) and Titmus stereoacuity, motor fusion range.


RESULTS
Postoperative acuity and improvement in visual acuity after removal of a uERM were better in patients with a shorter duration of symptoms. Stereoacuity was substantially reduced in the presence of a uERM (TNO, P<0.001; Titmus, P<0.001; Mann-Whitney U test), as were total motor fusion ranges at near and distance (near P = 0.002; distance P = 0.015; t test). Stereoacuity was worse in patients with symptoms of longer duration (TNO, P = 0.21; Titmus, P = 0.045; Spearman rank correlation). After successful surgery, stereoscopic function improved. This improvement occurred mainly in those patients with better preoperative stereoacuity and a shorter duration of symptoms.


CONCLUSIONS
Improvement in visual acuity after surgery was greater in patients with visual symptoms of shorter duration. A uERM adversely affected stereoscopic function, an effect that increased with time. The best monocular and binocular visual outcomes occurred in those patients who had earlier surgery.
Asaria
Riaz
R
Vitreo-retinal Service, Moorfields Eye Hospital, City Road, London, United Kingdom.
Garnham
Louise
L
Gregor
Zdenek J
ZJ
Sloper
John J
JJ
D000368:Aged; D000369:Aged, 80 and over; D003867:Depth Perception / Q000502:physiology*; D019773:Epiretinal Membrane / Q000503:physiopathology* / Q000601:surgery*; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015348:Vision, Binocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology*; D014821:Vitrectomy