Corneal topographic changes following strabismus surgery in Graves' disease

A computerized topographic analysis system was used to evaluate corneal changes after strabismus surgery in eight eyes of five patients with Graves' disease. All patients underwent inferior rectus muscle recession; three eyes also had medial rectus recession. Corneal topographic analysis revealed that, postoperatively, corneas steepened inferiorly and inferotemporally at 1.5 mm from corneal apex (p < 0.05). The opposite effect was observed in the superior quadrant (average flattening of 1.20 ± 0.32 D at 1.5 mm from corneal apex, and 1.08 ± 0.39 D at 3.0 mm from corneal apex; p < 0.05). Superotemporally, the cornea flattened by an average of 0.65 ± 0.26 D at 3.0 mm from corneal apex, and superonasally 0.72 ± 0.19 D at 3.0 mm from corneal apex (p < 0.05). Central, nasal, and temporal cornea did not show statistically significant changes. Spherical equivalent did not change significantly after surgery. The amount of restriction and upgaze measured preoperatively was correlated weakly with inferior corneal steepening (r² = 0.44; p = 0.046). These results are indicative that corneal topography may be influenced by strabismus surgery for Graves' disease through alteration of extraocular muscle tension or intraocular pressure.