Nine patients had a permanent
paresis of a vertical rectus muscle after
cataract extraction. We sought to determine the common factors associated with and their contribution to vertical
muscle paresis after
cataract extraction. The study design included a survey that was conducted among the referring
cataract surgeons and anesthesiologists with particular attention to surgical technique and
anesthetic administered, as well as a medical history and examination and appropriate laboratory tests. Patients had a complete ophthalmic examination including prism cover testing in all nine diagnostic positions, forced-duction testing, and saccadic velocity and generated muscle force estimation. The results of the study demonstrate no correlation between the
pareses and the use of a bridle
suture,
antibiotic or
corticosteroid injection, systemic disease, or surgical technique. Peribulbar
anesthesia was the most consistent feature in seven of the nine cases. In the other two, an atypical retrobulbar injection had been given. On the basis of the location of the
injections, the needle type, and the concentration and quantity of the
anesthetic injected, we conclude that permanent
pareses of a vertical rectus muscle may be caused by a myotoxic effect of the
local anesthetic.