Persistent diplopia and strabismus after cataract surgery under local anesthesia.

Background and purpose: Diplopia is an infrequent complication described for retrobulbar local anesthesia. The objective of this study is to report the clinical characteristics and treatments for this surgical complication.

Methods: Retrospective study of medical records.

Period: 5.3 years ending February 2005. During this period, 20453 cataract surgeries were performed. The anesthesia used was retrobulbar block with ropivacaine diluted with hyaluronidase. Nineteen patients reported diplopia due to strabismus after the cataract surgical procedure and were referred for evaluation at the Extrinsic Ocular Motility Department.

Results: Persistent diplopia after cataract surgery occurred in 19 (0.093%) of the 20453 cases. The types of deviations found were: exotropia (n=3), esotropia (n=5), hypertropia (n=1), exotropia + hypertropia (n=5) and esotropia + hypertropia (n=5). Small deviations and dysfunction of the lateral rectus muscles were most commonly seen. Prism was applied to 4 patients, eye muscle surgery was the option in 8 patients, orthoptic treatment was performed in 3 patients and for 2 patients the decision was to only observe progress. Overall, binocular vision was restored in eleven of the nineteen patients.

Conclusions: Persistent diplopia due to strabismus is an infrequent complication after cataract surgery with retrobulbar block. Etiology of this disorder of extrinsic ocular motility is variable, including mixed components. We stress the importance of adequate preoperative history of strabismus and evaluation of extrinsic ocular motility. Considering the reported incidence of this problem is as high as one in 25 cataract surgeries, one should advise the patient of the possibility of persistent postoperative diplopia and the possible need for surgical intervention and/or prism to treat the symptoms.