Experimental circular keratotomy for correction of corneal astigmatism.

PURPOSE

To investigate the effect of circular keratotomy depth and diameter on corneal astigmatism.

METHODS

High astigmatism was induced in 25 human donor eyes by an anterior radial 7-0 silk suture across the corneoscleral limbus. With a 6.0, 6.5, 7.0, or 7.5 mm trephine, a 0.3 mm deep circular incision was made in 20 donor eyes. In 5 donor eyes 5 circular incisions were made with a diamond knife set at 0.1, 0.2, 0.3, 0.4, and 0.5 mm depths.

RESULTS

The reduction of astigmatism between the 4 groups in which different trephination diameters were used showed no statistically significant difference (P > .1). The relationship between incision depth and reduction of astigmatism was statistically significant (P < .001).

CONCLUSION

Artificially induced corneal astigmatism was reduced by a circular keratotomy in this donor eye model. Deeper incisions showed a greater effect.