To evaluate factors associated with the development of strabismus after cataract extraction and primary intraocular lens implantation.

Medical records of 80 patients who had undergone cataract extraction with primary intraocular lens implantation between 6 months and 21 years of age from March 1993 to March 2008 were reviewed. Nine patients (11 eyes) with strabismus before cataract surgery were excluded. Patients were divided into 2 groups; patients with congenital bilateral cataracts (43 patients, 86 eyes) or patients with unilateral cataracts (28 patients, 28 eyes). Data were collected on age at cataract surgery, pre and post-cataract extraction visual acuity, interocular visual acuity differences, nystagmus, operation method, and the existence of associated other ocular diseases to evaluate the association of the onset of strabismus and after cataract.

Factors statistically significantly associated with the development of strabismus include presence of nystagmus in bilateral cataracts and postoperative visual acuity differences > 0.3 in unilateral cataracts. A post-cataract extraction mean visual acuity ≤ 0.2 and preservation of posterior capsule were significant factors in both groups.

Children with congenital cataracts should be monitored carefully after cataract surgery for the development of strabismus especially when they have poor postoperative visual acuity, nystagmus, large postoperative interocular visual acuity differences, or preservation of posterior capsule.