Corneal thickness, curvature may signal haze development after corneal collagen cross-linking

J Refract Surg. 2009;25(9):824-828.

Stage of keratoconus, defined by keratometry value and corneal thickness, may signal the development of corneal haze after riboflavin ultraviolet A corneal collagen cross-linking, a study showed.

"Advanced keratoconus should be considered at higher risk of haze development after [cross-linking] due to low corneal thickness and high corneal curvature," the study authors said.

The retrospective study included 163 eyes of 127 patients with stage 1 to stage 3 keratoconus. Patients underwent examination of uncorrected visual acuity, best corrected visual acuity, slit lamp biomicroscopy, corneal topography and corneal thickness before surgery and at all follow-up points up to 1 year.

One year after cross-linking, 149 eyes of 114 patients showed a clear cornea without stromal haze. These patients were assigned to a control group. Fourteen eyes of 13 patients developed clinically significant stromal haze. These patients comprised a haze group.

Preoperatively, the haze group had a mean keratometry value of 71.1 D and the control group had a mean keratometry value of 62.1 D. The haze group had a mean corneal thickness of 420 µm. The control group had a mean corneal thickness of 478 µm.

The haze group and control group had similar preoperative UCVA and BCVA. Postoperatively, UCVA and BCVA were improved in the control group but diminished in the haze group, the authors said.