Effect of Epithelium-Off Corneal CXL on Visual Acuity, Spherical Equivalent, and Corneal Topography in Patients With Keratoconus or Post-Refractive Corneal Ectasia
To evaluate changes in best corrected visual acuity (BCVA), spherical equivalent (SE), and corneal topography status-post epithelium-off corneal collagen crosslinking (CXL) with phototherapeutic keratectomy (PTK) or photorefractive keratectomy (PRK) in patients with mild to moderate keratoconus or post-refractive corneal ectasia.
This is a retrospective chart review of 8 eyes with keratoconus and 1 eye with post-refractive corneal ectasia that underwent epithelium-off CXL in combination with either PTK (n=4) or PRK (n=5). Riboflavin was administered every 30 seconds for 15 minutes followed by exposure to ultraviolet light using the UV-360 Crosslink device (New Vision, Inc.) at 25 mW for 6, 30 second sessions. BCVA, SE, and computerized corneal topography pre and post-CXL were analyzed. All topography and BCVA were performed by a single ophthalmic technician and confirmed by an ophthalmologist or optometrist. Data was analyzed using paired t-tests.
Ongoing study, results for 1-month follow-up presented, results will be updated. Mean age of all eyes undergoing treatment was 36.7 +/- 9.3 years. Average BCVA pre-CXL was 20/34, which improved to 20/24 post-CXL, resulting in a gain of 0.15 logmar (p=0.32). Average pre-CXL SE was -2.49 and decreased to -2.11 post-CXL (p=0.81). Average pre-CXL steep keratometry values were 47.37, and post-CXL steep keratometry values were 45.16, resulting in a decrease of 2.21 (p=0.46). No statistically significant changes in any of the variables studied were appreciated when all data was analyzed together or when divided into subgroups of PRK or PTK.
Short-term results indicate a decrease in SE and steep keratometry values with an increase in BCVA post-CXL. Longer follow-up with larger patient populations are necessary to draw conclusions regarding the impact of epithelium-off CXL on patients with KCN and post-refractive corneal ectasia.