Paired arcuate keratotomy for congenital and post-keratoplasty astigmatism

To study the effect of arcuate keratotomy on corneal astigmatism in previously grafted eyes compared to eyes with naturally occurring astigmatism.

Twenty-three eyes with naturally occurring astigmatism and 21 eyes with post-keratoplasty astigmatism were treated by arcuate keratotomies in the steepest corneal meridian. Visual acuity, spherically equivalent refraction, and refractive cylinder were measured before surgery and 1 to 10 years after the operation.

The preoperative refractive cylinder was reduced from 5.0 dioptres (median) to 1.25 dioptres in eyes with natural astigmatism and from 7.0 dioptres to 3.25 dioptres in post-keratoplasty eyes. Spherical equivalent refraction changed from -0.6 dioptres to -1.5 dioptres in eyes with natural astigmatism and from -3.5 dioptres to -4.5 dioptres in previously grafted eyes. The induced change in astigmatism, as calculated by Fourier analysis, correlated strongly with the existing preoperative astigmatism. The effect of the procedure did not correlate with the type of astigmatism (congenital vs. post-keratoplasty), time after surgery, or with patient age or sex.

Arcuate keratotomy is a simple procedure to reduce naturally occurring astigmatism as well as induced astigmatism after keratoplasty. Parallel to the astigmatic change, negligible changes in the spherical equivalent are induced.