Abstract
Purpose::
The increase of the prevalence of anisometropia with age has been reported (Weale, 2002), however it is not well investigated if eye position influences the development of anisometropia. In this study, we investigated the relationship between eye position and anisometropia in postoperative patients with esotropia (ET).Subjects: Consecutive 63 patients of ET (except full accommodative ET) who visited Osaka University Hospital between 1991 and 2005 and underwent strabismus surgery were retrospectively studied. Patients with amblyopia and/or anisometropia equal or greater than 2 diopters (D) were excluded. The preoperative difference of refraction between two eyes was 0.4±0.5D . The age of surgery ranged from 1 to 37 years (average: 6.0±6.6years).
Methods::
Refraction, eye position, and angle of strabismus were measured postoperatively. The postoperative follow-up period was more than 1 year (average, 4.4±2.3 years). The angle of strabismus was measured by the alternative prism cover test (APCT). The dominant eye at far and at near was determined by the fixating eye when prism cover test was performed. We defined a patient developed anisometropia, in which difference of refraction between two eyes increased to more than 2D during follow-up period. Postoperatively we classified a patient as orthophoria (OT) if the far angle of strabismus was within ±8 prisms, as ET greater than + 8 prisms, and as exotropia (XT) more than - 8 prisms.
Results::
At final visit, the average difference of refraction between two eyes was 0.9±1.2 D. There was no correlation between follow-up period and the type of postoperative eye position. The number of patients of postoperative OT, XT, and ET was 22, 20, and 21. Anisometropia developed in 3 in OT (14%), 5 in XT (25%), and 2 in ET (9%) group. In all 10 postoperative anisometropia patients, the near dominant eye was more myopic compared with the fellow eye.
Conclusions::
Anisometropia tended to develop more in a group of postoperative exotropia after the strabismus surgery of esotriopia. It may be suggested to pay attention not only to the eye position but also to the anisometropia after surgery of esotropia.
Keywords: strabismus • refractive error development • strabismus: treatment