Evaluation of penetrating keratoplasty in keratoconus. Nine years follow-up.

Penetrating keratoplasty was done in 104 cases with keratoconus. The donor material were preserved either as a whole eye in moist chamber at 4 degrees C, or as a corneoscleral segment in MK-medium at 4 degrees C, or in a tissue culture. The post-operative observation time varied between 6 months and 9 years. The visual acuity was found to be better than before surgery in 96%, unchanged in 3%, and worse in 1% of the cases. The average visual acuity was found to be after 6 months 0.25 +/- SD 0.2 and after 7 years 0.65 +/- SD 0.23. The post-operative spherical error of refraction was found to be -3.26 +/- SD 3.5 D, and the post-surgical astigmatism -2.6 +/- SD 1.9 D.