Collagen Cross-linking (CXL) For Keratoconus With Simultaneous Topographical-guided Photorefractive Keratectomy (TG-PRK)

1. Dr. David T.C Lin^1,2
2. Dr. Simon Holland^1,2

¹Pacific Laser Eye Centre, Vancouver, British Columbia, Canada
²University of British Columbia, Eye Care Centre, Vancouver, British Columbia, Canada

Purpose: To evaluate early results of efficacy and safety of simultaneous TG-PRK with collagen cross-linking.

Methods: 105 eyes of 72 patients with contact lens intolerant keratoconus (KC) underwent TG-PRK with an Allegretto Wavelight laser with simultaneous CXL. Degree of refractive correction based on residual stromal depth of 300 microns. Pre-operative vision (UCVA), best corrected vision (BSCVA), keratometry (K), efficacy, and safety were evaluated at one year.

Results: 32 eyes completed one year follow-up, 22 (70%) had UCVA of 20/40 or better with all achieving BSCVA of 20/40 or better. 19 (59 ) increased BSCVA , 8 (25) no change, 4 (12) lost one line, and one incomplete. Mean astigmatism decreased from -2.60 diopters (D) pre-operatively to -1.05 D at one year. Only 5/22 was using refractive correction at 1 year with symptom improvement in 19/22. Complications included delay in epithelial healing beyond one week in four and one developed herpetic keratitis with all five recovering pre-operative BSCVA.

Conclusions: Simultaneous topographically-guided PRK with CXL offers promising early results for contact lens intolerant KC. Improved uncorrected vision was obtained in 70%, but the extent of refractive correction is limited by low pachymetry in keratoconus.