Abstract
Purpose:
To investigate outcomes after surgery for intermittent exotropia with a high accommodation convergence-accommodation (AC/A) ratio.
Methods:
The records of patients who underwent surgery for intermittent exotropia with a high AC/A ratio between July 2008 and August 2011 and had at least 6 months of postoperative follow-up were reviewed. After 1 hour of monocular occlusion of the habitually deviating eye to determine the presence of tenacious proximal fusion, prism cover test measurements at 6 m and 33 cm were done. AC/A ratios were calculated using the gradient method with +3.0 D lenses at 33 cm. Extent of operation was determined on the basis of the largest angle at distance. Pre- and postoperative deviation at near and distance, AC/A ratio, and near stereoacuity were analyzed. Surgical results were considered successful if the post-operative angles were between 10 prism diopters (PD) of exophoria/tropia and 8 PD of esophoria/tropia at final follow-up.
Results:
Eleven patients were included in the final analysis. Mean age at surgery was 7.6 ± 2.2 years with a range of 5 to 12 years. The mean preoperative angle of exodeviation at near and distance and AC/A ratio were 5.7 ± 6.7 PD, 25.8 ± 6.8 PD and 7.3 ± 2.4 PD/D respectively. After a mean follow up of 19.9 ± 7.7 months, successful results were obtained in six patients, but three patients had recurrence and two patients required bifocal correction for esotropia at near. AC/A ratios in all patients decreased after surgery. All overcorrected patients had very high AC/A ratio over 8.0 PD/D and a history of previous strabismus surgery.
Conclusions:
In patients with intermittent exotropia and high AC/A ratio, surgical treatment results in favorable outcomes in cases of AC/A ratio less than 8 PD/D and no history of previous strabismus surgery.
Keywords: 725 strabismus: treatment