Efficacy of prism adaptation in the surgical management of acquired esotropia. Prism Adaptation Study Research Group
Prism adaptation, the preoperative use of prisms in acquired esotropia to
determine the maximum angle of strabismus and to estimate fusional
potential, has been suggested as a method of improving the results of
initial surgery and minimizing the rate of reoperation. We performed a
prospective, randomized, multicenter clinical trial of the effectiveness of
prism adaptation. Two levels of randomization were used. Sixty percent of
the patients underwent prism adaptation and 40% did not. Of those who
responded to prisms with motor stability and sensory fusion, half underwent
a conventional amount of surgery and half underwent augmented surgery based
on the prism-adapted angle of deviation. Success rates were highest (54
[89%] of 61 patients) in prism adaptation responders who underwent
augmented surgery and lowest (92 [72%] of 127 patients) in patients who did
not undergo prism adaptation. Prism responders had better results with
augmented surgery than with conventional surgery (54 [89%] of 61 patients
vs 53 [79%] of 67 patients, P = .23). Our results indicated a significant
beneficial overall effect of prism adaptation in patients with acquired
esotropia (success rates, 83% vs 72%, P = .04). Although the process
requires some additional time and effort, it appears to result in a higher
rate of satisfactory alignment.
