Corneal Densitometry and Higher Order Aberrations After Corneal Transplantation and Corneal Cross-Linking for Keratoconus: 3-Year Results.

PURPOSE

To compare the corneal densitometry and higher order aberrations (HOAs) following corneal cross-linking (CXL), deep anterior lamellar keratoplasty (DALK), and minimally invasive lamellar keratoplasty (MILK) for keratoconus.

METHODS

Twenty-five eyes treated with CXL (CXL group), 17 eyes treated with DALK (DALK group), and 25 eyes treated with MILK (MILK group) were included in this prospective study. Corneal densitometry and HOAs were evaluated preoperatively and at 1, 3, 6, 12, 24, and 36 months postoperatively.

RESULTS

In CXL and MILK, corneal densitometry values peaked at 1 month ( < .001), returned to the preoperative level at 6 months ( = .334, 0.224), and declined below baseline at 36 months ( < .001, = .129); the changes from preoperatively to 36 months postoperatively between groups were not significant ( = .713). In DALK, corneal densitometry values were still higher at 36 months than before surgery ( = .007). The root mean square value of total HOAs from the whole cornea was decreased by 0.192 ± 0.457, 0.823 ± 0.926, and 3.938 ± 1.873 µm at 36 months postoperatively for CXL, MILK, and DALK, respectively ( = .047, <.001, <.001); the differences between groups were all statistically significant. The total HOA or spherical aberration changes from the whole cornea correlated with maximum keratometry changes for CXL ( < .001; = 0.490), MILK ( < .001; = 0.599), and DALK ( < .001; = .558).

CONCLUSIONS

MILK and CXL showed a similar improvement in corneal densitometry. HOAs improved most in DALK, followed by MILK and CXL, corresponding to maximum keratometry changes. The coma and spherical aberrations improved in MILK and DALK, but not in CXL. .