To evaluate the effect of cauterization on extraocular muscle (EOM) fibrosis in rats, and to develop a novel EOM fibrosis model.

Twenty-four eyes of 12 Sprague Dawley rats were assigned randomly to two groups. We exposed the superior rectus muscle (SRM) and performed thermal injury 2 mm behind the insertion site of the SRM using a cautery device in the experimental group. The thermal injuries were performed twice for 1 second, for a total of 2 seconds. In the control group, the same procedures except the thermal injury were performed. Two weeks after surgery, all eyes were enucleated and stained with hematoxylin and eosin (H&E) and Masson's trichrome (MT).

Staining with H&E and MT showed that thermal injury significantly increased inflammation and fibrosis in the experimental group ( p =0.002, p <0.001, respectively).

Thermal injury using cauterization effectively induced fibrosis of EOM in the rat model. This simple model was effective in inducing fibrosis of SRM and will be useful for studying postoperative fibrosis after strabismus surgery.