A Prospective Study of Binocular Visual Function before and after Successful Surgery to Remove a Unilateral Epiretinal Membrane
Received 9 February 2008; received in revised form 10 April 2008; accepted 12 May 2008. published online 22 August 2008.
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.
Design
Cohort study.
Participants
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.
Main Outcome Measures
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.
Financial Disclosure(s)
The authors have no proprietary or commercial interest in any materials discussed in this article.
Available online: August 22, 2008.
1Vitreo-retinal Service, Moorfields Eye Hospital, City Road, London, United Kingdom
2Strabismus and Paediatric Service, Moorfields Eye Hospital, City Road, London, United Kingdom
Correspondence: John Sloper, DPhil, FRCOphth, Moorfields Eye Hospital, City Road, London EC1V 2PD
Manuscript no. 2008-192.
Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article.
ABSTRACT