Long Term Corneal Flattening After Corneal Crosslinking in Patients with Progressive Keratoconus

Abstract

Purpose

We evaluate the long-term visual, refractive, and keratometric outcomes after corneal crosslinking (CXL) in patients with progressive keratoconus (KC) and the incidence of an extreme corneal flattening effect.

Settings

Oftalmosalud Institute of Eyes, Lima, Perú.

Design

Retrospective cohort study.

Methods

Forty-five eyes that underwent CXL with epithelial removal between June 2006 and September 2011. Data analysis was performed at preoperative evaluation, 1 year postoperatively, and at least 10 years or more postoperatively. Outcome measures included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and Scheimpflug (Pentacam) analysis. Progression was defined by an increase in steep keratometry (Ks) of 1.5D or greater between 2 examinations. Extreme flattening effect was defined as a decrease in K values equal to or greater than 5 diopters (D).

Results

Mean follow-up time was 11 ± 1.07 years (range 10–13 years). There was a significant improvement in Ks, UCVA, CDVA, and spherical equivalent at the last visit. The overall rate of progression was 2.22% (1/45). Extreme flattening was observed in 15.5% (7/45) of the eyes, and this was associated with a loss of CDVA in 4.44% (2/45) of the eyes. One eye with corneal flattening of 11.5 D lost 7 lines of CDVA and required corneal transplantation.

Conclusion

CXL is a safe and effective procedure to stop the progression of KC with a good overall long-term success rate. Extreme corneal flattening may be more common than commonly recognized, and severe corneal flattening associated with a decrease in CDVA may occur.

Keywords:

• crosslinking
• keratometric flattening
• keratoconus
• CXL

Acknowledgment

Jose Chauca MSc, for statistical analysis. Coffeen M, for English grammar edits.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

The authors received no financial support for this study.