Abstract
Abstract: :
Purpose: Differences between bilateral recession (BR) and recession-resection (RR), the most common surgical procedures for horizontal strabismus, have never been assessed in a randomised study. Methods: 9 German and 5 Dutch clinics recruited 3- to 8-year-old children with infantile esotropia. Exclusion criteria were: previous surgery, binocular vision (including Bagolini), near angle / far angle ≷ 3/2, far angle ≷ 24° or < 10°, acuity 1 line acuity difference, large hypermetropia or myopia, substantial up- or downshoot, V- or A-pattern or manifest hypertropia ≷ 4°. The day before surgery, the latent angle at distance fixation in degrees was divided by 1.6 to obtain millimeters of recession and/or resection. Then the child was randomised to receive either BR or RR surgery the following day. Uniform guidelines on orthoptic and operative techniques were enforced by regular visits and photographs taken during surgery. Primary outcome measures were angle with alternating cover at distance fixation and remaining convergence excess, 3 months postoperatively. Results: 120 children will have been operated at conclusion of the study on December 31st 2001. Preliminary analysis without breaking the code (n=85) showed no difference between BR and RR. Average effect was only 1.4° per mm, s.d. 0.4. A smaller preoperative angle was correlated with less effect. Conclusion: This prospective, randomised, controlled study failed to confirm purported differences between BR and RR in effect on angle with alternating cover at distance fixation. Cases with a preoperative angle <15° had less average effect. The average effect was approx. one s.d. below current guidelines for horizontal strabismus surgery, reflecting the tendency to avoid overcorrection.
Keywords: 588 strabismus • 591 strabismus: treatment • 357 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials