Refractive Outcomes of Topography-Guided Photorefractive Keratectomy With Simultaneous CXL for Keratoconus

Monday, April 28, 2014: 3:36 PM
Room 151B (Boston Convention and Exhibition Center)
David T. Lin, MD, FRCSC, Pacific Laser Eye Centre, Vancouver, BC, Canada
Simon P. Holland, MB, FRCSC, University of British Columbia, Vancouver, BC, Canada
Johnson Tan, MBBS, FRCSEd (Ophth), The University of British Columbia, Vancouver, BC, Canada

Narrative Responses:

Purpose
To evaluate efficacy and safety of topography-guided photorefractive keratectomy (TG-PRK) with collagen cross-linking (CXL) for keratoconus (KC

Methods
Retrospective case series of 365 eyes with contact lens (CL) intolerant KC undergoig TG-PRK with Allegretto Wavelight (AW) laser using Topographic Neutralization with simultaneous CXL. Epithelial removal by trans-epithelial laser, riboflavin 0.1% until aqueous staining, UV irradiation 370nm for 8-15 minutes at 3mW/cm2 - 5.4 J/m2. Refractive correction planned to leave residual stromal depth of 300 microns with target correction of -1.25 diopters(D). Symptom score (10 point), uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), efficacy, and safety were evaluated at 12 months

Results
165 eyes completed 12 months follow-up.  82 eyes (49%) had UCVA of 20/40 or better.  26 eyes (16%) had UCVA of 20/25 or better. 81 eyes (49%) had BSCVA improved, 45 eyes (27%) gained 2 lines or more, 5 eyes (4%) lost 2 lines or more.  Average symptom score improved from 6.7 to 4.2 Mean reduction of astigmatism was 1.52 diopters (D).  .  Complications included 7 with delay in epithelial healing, 4  with subsequent haze, 2 sufficient to reduce BCVA more than 2 lines, with one undergoing keratoplasty. One  developed herpetic keratitis recovering pre-operative BCVA after PTK.

Conclusion
Satisfactory efficacy and safety were achieved after simultaneous topography-guided PRK with CXL.  At one-year follow-up, almost half achieved UCVA of 20/40 or better with one third improving 2 or more lines of BSCVA.  The combined technique of CXL with customized TG PRK offers promising results for CL-intolerant KC patients.