Quantitative measurement of wound spreading in radial keratotomy.

BACKGROUND

Many studies of radial keratotomy have been performed, however quantitative laboratory evaluation of the biomechanics of this procedure is still incomplete. Furthermore, most measurements of strain in the past have utilized strip testing, thus destroying the normal physiological structure and water balance of the cornea.

METHODS

We report on a membrane inflation method of wound spreading in intact human corneas using the Baribeau Micronscope.

RESULTS

We measured a secant elastic modulus of 7.58 x 10(6) N/m2 between 25 and 100 mm Hg. The spreading of radial keratotomy incisions as a function of intraocular pressure showed a maximum spreading of approximately 50 mu at 25 mm Hg at a radius of 3.50 mm from the optical center. A slight increase in spreading was observed in proceeding from a single to four radial incisions.

CONCLUSIONS

Quantitative measurement of wound spreading is an important parameter of radial keratotomy and can provide important information regarding opposing theories of the biomechanics of this operation.