Strabismus and diplopia as complications after cataract surgery with IOL implantation

In our Department of Orthoptics we have seen an increasing number of patien ts suffering from diplopia after cataract surgery with IOL implantation. Be tween 1993 and 1997 the total number of patients with this problem was 24 ( 2.7 % of all patients, mean age 71 years, age range 38-88). We addressed th e question of whether there is a common pattern of motility dysfunction. Methods: After evaluation of the clinical history and the basic ophthalmolo gical findings the following parameters were examined: binocular function ( Bagolini test), squint angles (Maddox cross), ocular motility. Results: The 24 patients could be divided up into three groups. Group 1 con sisted of 9 patients (mean age 82 years, range 64-88) who complained about diplopia because of strabismus incomitans with vertical deviation and restr icted motility on the first day after surgery. In 8 of the 9 patients strab ismus surgery was done. Group II consisted of 10 patients (mean age 66 year s, range 38-77) who noticed diplopia and strabismus within 7 days after sur gery. We found various kinds of heterotropia. Seven of these patients were operated on and two had a prism correction. Group III consisted of 5 patien ts (mean age 67 years, range 61-78). Their already known strabismus paralyt icus or concomitans deteriorated, leading to diplopia in some cases. All pa tients in this group were operated on. Discussion: For group I we believe that retro-, para- or peribulbar anesthe sia caused the motility dysfunction. In groups II and III it is unlikely th at local anesthesia had a causative role. The prolonged disruption of binoc ular vision and the abrupt change in the sensory situation after the catara ct operation with lens implantation may be the leading causes for strabismu s or deterioration of a preexisting strabism, respectively. Conclusions: These patients need a subtil meticulous diagnostic work-up and followup because of the possibility of early surgical therapy, which has a good prognosis. Evaluation of binocular vision and eye movements prior to cataract surgery appears to be helpful for later strabismic surgery.