Hydroxypropylmethylcellulose and sodium hyaluronate in adjustable strabismus surgery.

The efficacy of hydroxypropylmethylcellulose and sodium hyaluronate as adjuncts during adjustable strabismus surgery was evaluated experimentally. Fifteen randomized NZA rabbits underwent a bilateral 4-mm recession of the superior rectus followed by a 0.05 mL injection of submuscular hydroxypropylmethylcellulose 2% (HPMC) in one eye and sodium hyaluronate 1% (Healon) in the other eye. Five additional rabbits (10 eyes), used as controls, underwent the same procedure, but no viscoelastic was injected after surgery. The force needed to move the muscle 4 mm toward its original insertion was measured immediately and 24 hours after the operation, using a force gauge. The force needed to adjust the muscles increased 326.0%, 98%, and 124.7%, respectively in the control, Healon and HPMC groups (p < 0.001). No significant difference was found between the two viscoelastic substances. Histologic evaluation of the operation sites disclosed similar inflammation in both controls and viscoelastic groups (p = .5960).