Up-slanting palpebral fissures and oblique astigmatism associated with A-pattern strabismus and overdepression in adduction in spina bifida

Abstract

Purpose: To describe the spectrum of adnexal and ophthalmologic features in spina bifida.

Methods: A retrospective review of the medical records of 73 patients was conducted. Data concerning ocular motility, palpebral fissure orientation, presence and axis of astigmatism, visual acuity, amblyopia, and stereopsis were analyzed.

Results: Forty-three (59%) of the 73 patients had strabismus: 28 (65%) had esotropia, 12 (28%) had exotropia, and 3 (7%) had orthotropia in primary gaze and a significant A-pattern. Of the strabismic patients, 20 (47%) had an A-pattern, of which 13 (65%) demonstrated overdepression in adduction. Twenty-seven (84%) of the 32 patients with documented palpebral fissure orientation had exaggerated up-slanting palpebral fissures. Forty-nine (77%) of 64 patients exhibited astigmatism greater than 0.75 D in at least 1 eye, with a mean power of 1.6 D. The axis of cylinder was oblique in 76% of these patients. The astigmatic axis was consistently oriented perpendicular to the eyelid fissure orientation in the group of patients with up-slanting palpebral fissures, with the mean axis of cylinder being incyclorotated (OD axis, 77; OS axis, 108). Up-slanting palpebral fissures were associated with a 15-fold increased chance that the axis of cylinder would be incyclorotated (P =.07, chi-square test). An orbital computed tomographic (CT) scan of a spina bifida patient with A-pattern esotropia, overdepression in adduction, and up-slanting palpebral fissures demonstrated significant incyclorotated extraocular muscle pulley heterotopy.

Conclusions: Exaggerated up-slanting palpebral fissures are a prominent feature in spina bifida. Up-slanting palpebral fissures in spina bifida patients are associated with incyclorotated oblique astigmatism, A-pattern strabismus, and overdepression in adduction. These associations might be related to an anomaly of orbital skeletal or extraocular muscle pulley development. Further prospective study is encouraged.