Abstract
Purpose: :
To manage intermittent exotropia, maintenance of phoria is important. We investigated the relationships between phoria maintenance and suppression of physiologic diplopia.
Methods: :
Subjects were 50 patients with intermittent exotropia, who were under 15 years old and could be examined for suppression of physiologic diplopia. Deviations at near and far distances were 20.3±9.3 PD and 18.0±8.7 PD, respectively. Suppression under phoria condition was evaluated by physiologic diplopia test. Suppression under tropia condition included tropia phase and when convergence broke. While focusing on the relationships between phoria maintenance and suppressions under both phoria and tropia conditions, we also investigated the associations between the non-dominant eye and deviating eye when convergence broke, and between the dominant eye and dominant hand.
Results: :
Of the 50 patients, 22 (44.0%) showed suppression of physiological diplopia under phoria condition. Eighteen (81.8%) of the 22 patients also indicated suppression when convergence broke and could not maintain phoria. Nineteen (67.9%) of the remaining 28 patients who did not suppress under phoria condition could maintain phoria. These results indicated a significant correlation between phoria maintenance and suppression under phoria condition (p<0.001). Only 44 subjects could be examined for suppression under tropia condition and 20 (45.5%) showed suppression under phoria/tropia conditions and 19 (43.2%) did not suppress under either phoria or tropia condition. Eighteen (90%) of the 20 patients could not maintain phoria and 11 (57.9%) of the 19 patients could maintain phoria. A significant correlation was seen between phoria maintenance and suppression under phoria/tropia conditions (p<0.001). This result suggested that patients who suppressed under both conditions could not maintain phoria. The non-dominant eyes and deviating eyes when convergence broke (p<0.001) as well as the dominant eyes and dominant hands (p<0.05) significantly corresponded.
Conclusions: :
Not only suppression under tropia condition but also suppression under phoria condition can affect the maintenance of phoria in intermittent exotropia.
Keywords: esotropia and exotropia • binocular vision/stereopsis • strabismus