Scleral perforations in strabismus surgery: incidence and role of prophylactic cryotherapy--a clinical and experimental study.

PURPOSE: To determine the incidence of scleral perforations in strabismus surgery in a tertiary centre setting in India and to evaluate the risk or benefit, if any, of prophylactic cryotherapy following experimental scleral perforations in rabbits.

METHODS

Seven hundred eyes of patients that had undergone strabismus surgery (1121 procedures) were examined postoperatively by indirect ophthalmoscopy. In the experimental component, 20 rabbit eyes were perforated with a 6-0 polyglactin suture. In each rabbit, one eye acted as a control while the other eye received a 20 seconds application of prophylactic cryo at the perforation site. They were then monitored for 6 weeks before subjecting some to histopathological examination by light and electron microscopy.

RESULTS

Ten scleral perforations were detected in 9 of the patients (incidence of 1.42% of the eyes and 0.89% of the strabismus procedures). In the rabbits, a chorioretinal scar was seen in all perforated eyes. A mild cryo reaction was observed in the cryoed eyes. No other sequelae were seen. Histopathologic studies showed changes consistent with the normal healing process.

CONCLUSIONS

Of the human eyes screened, 1.42% showed evidence of scleral perforation following strabismus surgery. In no case were sequelae leading to visual loss observed. In the rabbits no sequelae were observed at 6 weeks of follow-up apart from a chorioretinal scar and a cryoreaction in those eyes in which cryoprophylaxis had been given. Mild cryoprophylaxis did not exert any positive or negative influence on the natural course of scleral perforation in our short-term animal study.