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Refractive outcomes of topography-guided photorefractive keratectomy with simultaneous cross-linking for keratoconus

Session Details

Session Title: Keratoconus and ectasia

Session Date/Time: Tuesday 08/10/2013 | 16:30-18:00

Paper Time: 17:09

Venue: Elicium 2 (First Floor)

First Author: : D.Lin CANADA

Co Author(s): :    S. Holland   G. Moloney   J. Tan        

Abstract Details

Purpose:

Refractive outcomes of Topography-guided photorefractive keratectomy with simultaneous cross-linking for keratoconus

Setting:

Laser eye centre.

Methods:

Retrospective case series. 335 eyes with contact lens intolerant KC underwent TG-PRK with Allegretto Wavelight (AW) laser using custom Topographic Neutralization Technique 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. Hypotonic riboflavin used if pachymetry is less than 400um, followed by bandage contact lens and standard post PRK management. Degree of refractive correction was based on 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:

112 eyes completed 12 months follow-up. 50 eyes (45%) had UCVA of 20/40 or better. 64 eyes (57?) had BSCVA improved, 38 eyes (34?) gained 2 lines or more, 7 eyes (6%) lost 2 lines or more. Average symptom score improved from 6.7 to 4.2 (rating from 0 to 10, 10 being worst). Mean astigmatism decreased from -2.82D preoperatively to -1.28D postoperatively. Mean postoperative refractive spherical equivalent (SE) regressed from -0.89 at 3 months post-operatively to -1.14 at 12 months with 16 eyes (13%) having hyperopic progression. 4 eyes had hyperopia spherical equivalent >1.50D. Complications included one herpetic keratitis, 5 delayed epithelial healing beyond 1 week and two requiring penetrating keratoplasty for advanced haze and loss of 4 lines of BSCVA.

Conclusions:

Early satisfactory refractive outcomes were obtained with simultaneous topography-guided PRK with CXL. Progressive hyperopia probably related to cross linking, sufficient to be visually significant, occurred in 4 eyes. AW ablation induces myopia in most treatments, and may explain why a greater hyperopic SE did not occur. At one-year follow-up, just less than half of the eyes achieved UCVA of 20/40 or better and a third improved 2 or more lines of BSCVA. The combined technique of CXL with customized TG PRK offers promising results for CL-intolerant KC patients.

Financial Interest:

NONE