Abstract
Purpose: :
Because control of phoria is important for managing intermittent exotropia, we investigated how the maintenance of phoria could be affected by suppression of physiological diploia.
Methods: :
Subjects were 50 patients with intermittent exotropia, who were under 15 years old (mean age, 9.0±2.3 years) and could be examined for suppression of physiologic diplopia. Thirty-four of the 50 patients had received one operation, orthoptic training, or both previously; and 23 of the 34 patients could maintain phoria after treatment. Deviations at near and far distances were 20.3±9.3PD and 18.0±8.7PD, respectively. Presence of suppression was assessed under phoria condition by physiologic diplopia test and when convergence broke. Relationships between phoria maintenance and suppression, non-dominant eye and deviating eye when convergence broke, and dominant eye and dominant hand were all investigated.
Results: :
Twenty-two (44.0%) of the 50 patients showed suppression of physiological diplopia under phoria condition, and 18 (81.1%) of the 22 patients also indicated suppression when convergence broke. A significant correlation was seen between suppression under phoria condition and when convergence broke (p<0.001). Twenty-three (46%) of the 50 patients indicated phoria maintenance and only 2 (8.7%) of them showed suppression under both conditions. This indicated that patients capable of phoria maintenance did not suppress under phoria condition and when convergence broke. In those 27 patients not capable of phoria maintenance, 16 (59.3%) were seen with suppression under both conditions. This suggested that patients not capable of phoria maintenance suppressed under phoria condition and when convergence broke. A significant correlation was seen between the presence of suppression and the maintenance of phoria (p<0.001). Deviating eye when convergence broke and non-dominant eye corresponded in 87.1% of the 50 patients. Dominant eye and dominant hand corresponded in 68.0%.
Conclusions: :
Under phoria condition, patients who can maintain phoria condition did not suppress. This shows the association between the presence of suppression and maintenance of phoria.
Keywords: binocular vision/stereopsis • strabismus • esotropia and exotropia