The Association of Ocular Dominance and the Preferred Eye for Fixation in Intermittent Exotropia: A Guide to Choosing the Eye for Unilateral Surgery

Abstract

Objective

Recession of the lateral rectus muscle of the more frequently deviating eye in patients with small-angle intermittent exotropia has yielded good results. However, sometimes neither history nor clinical examination can identify this eye. This study sought to determine if the dominant eye of patients with intermittent exotropia is the preferred eye for fixation i.e., not the more frequently deviating eye.

Methods

We recruited 40 patients (33 males, 7 females) aged 2.5 to 44.0 years (mean 9.5, SD 8.7) who had intermittent exotropia and attended our eye clinic between September 1998 and April 1999. Exclusion criteria included age (patients too young to cooperate), previous strabismus surgery, poor vision, neurological disorders or abnormal ocular motility, and unsuccessful determination of the preferred eye for fixation from history and examination. The preferred eye for fixation was determined by an orthoptist using cover tests, the dominant eye by an ophthalmologist using sighting and convergence near-point tests.

Results

Tests showed that the dominant eye was almost invariably the same eye as the preferred eye for fixation.

Conclusions

For patients who have small-angle intermittent exotropia, when the more frequently deviating eye cannot be definitely determined before unilateral surgery, the sighting test can help identify the dominant eye.

• dominant eye
• preferred eye for fixation
• intermittent exotropia
• sighting test
• convergence near-point test