LONG-TERM REFRACTION AND KERATOMETRY AFTER PENETRATING KERATOPLASTY FOR KERATOCONUS

We looked for continued corneal ectasia after penetrating keratoplasty (PK) for keratoconus by measuring longterm changes in keratometry and refraction after final suture removal. The records of 587 patients wh o had had PK for keratoconus and who had attended a single center over a 7-year period were examined. For 184 eyes keratometry or refraction data were available from the first operated eye from the 6-month inte rval after final suture removal, and, in these patients, these reading s were repeated as they continued to be seen for review. The changes i n mean keratometry, spherical equivalent, and cylinder over the period of follow-up were then calculated, and these data were assessed by re gression analysis. We found no significant change with time in the amo unt of cylinder when measured by either refraction or keratometry. The re was a trend (p = 0.075) toward an increase in the mean keratometry with rime, suggesting a gradual flattening of the cornea, and there wa s a clinically small, but statistically significant (p < 0.001), time- dependent increase in the residual myopia in the years after final sut ure removal. In conclusion, we found a wide range in the individual va lues for changes in keratometry or refraction in the years after sutur e removal following PK for keratoconus but no evidence overall to sugg est continued corneal ectasia or a recurrence of keratoconus in these grafts.