Comparison of the protective effects of methylcellulose and sodium hyaluronate on corneal swelling following phacoemulsification of senile cataracts.

The protective effects of two viscoelastic substances (hydroxypropyl methylcellulose and sodium hyaluronate) on the cornea during phacoemulsification of senile cataracts were investigated in a prospective, randomized, clinical study. The viscoelastic substances were placed in the anterior chamber before and during phacoemulsification. The mean increase in central corneal thickness (measured by ultrasonic pachymetry) on the first postoperative day was statistically significantly higher (P less than .05) in the methylcellulose group (35 eyes) than in the sodium hyaluronate group (35 eyes). Five weeks postoperatively the difference in mean central corneal thickness between the two groups was not statistically significant. However, one eye in the methylcellulose group developed bullous keratopathy. The present study indicates that methylcellulose does not protect the corneal endothelium as effectively as sodium hyaluronate during phacoemulsification procedures.