Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Cumulative frequency distribution of (left) mean keratometric corneal power and (right) astigmatism at 1 month after suture removal (13 months after PK) and at last follow-up (if at least 15 years) after penetrating keratoplasty for keratoconus. The gray area between the 2 stepped lines represents the increase in postoperative corneal steepening or astigmatism.
