[Diplopia complicating peribulbar anesthesia for cataract surgery and early use of MRI].

OBJECTIVE

To evaluate the early use of magnetic resonance imaging (MRI) for the diagnosis of diplopia following cataract surgery under peribulbar anaesthesia.

STUDY

DESIGN

Single centre prospective study.

PATIENTS AND METHOD: From January 2003 to January 2005 every patient undergoing cataract surgery under peribulbar anaesthesia was included. Any patient spontaneously complaining of double vision on day 1 received a full ophthalmologic examination. When binocular diplopia was confirmed by a positive Hess-Lancaster test, the patient immediately underwent an MRI.

RESULTS

During the two year period, 4805 patients underwent cataract surgery under peribulbar anaesthesia. Eight patients reported double vision on day 1 (0.16% prevalence). Clinical examination confirmed binocular diplopia and a positive Hess-Lancaster test identified the paralysed muscle. In 7 out of 8 patients, the MRI performed on the same day showed a T2 hyper intensity signal within the paralysed muscle, it was interpreted as inflammatory oedema following an accidental intra muscular injection of a myotoxic local anaesthetic. In one patient the MRI was normal, suggesting a preoperative undiagnosed diplopia having no relation to the peribulbar anaesthesia.

CONCLUSION

A slit-lamp exam and a Hess-Lancaster test are necessary to confirm postoperative strabismic diplopia after cataract surgery. An early MRI can accurately distinguish postanaesthetic myotoxic diplopia from a preoperative diplopia revealed by the corrective cataract surgery.