Abstract
Purpose :
Current treatment protocols to halt the progression of keratoconus only take into account patients with pachymetry measurements greater than 400 microns for crosslinking procedures. Patients below this threshold are not offered an alternative to stop the progression of keratoconus. The present study aims to evaluate the efficacy and safety of the sub-400 protocol.
Methods :
This study was designed as a prospective, longitudinal, and experimental investigation that included 34 patients with keratoconus progression data, whose corneas had a thickness below 400 microns. The corneal epithelium was removed, followed by the instillation of isotonic 0.1% riboflavin for 10 minutes. Ultrasonic pachymetry was utilized to measure corneal thickness following riboflavin instillation, and corneal irradiation was performed at 3mW/cm2, with an individualized duration according to the sub-400 protocol. Evaluated parameters included pre- and postoperative endothelial cell count, best-corrected visual acuity, refraction, pachymetry, and corneal tomography values (Oculus Pentacam) to assess the efficacy and safety of the procedure.
Results :
A total of 34 patients underwent the intervention within an age range of 16 to 22 years, with a female representation of 60%. Notably, 83.33% of the patients exhibited a delineation line. In the analysis of best-corrected visual acuity, a notable improvement of 1 to 2 lines of vision was observed. Post-procedural pachymetry demonstrated a noteworthy trend towards reduction (p < 0.001), while both maximum and minimum curvature remained unaltered. Endothelial cell loss did not reach statistical significance (p = 0.07). Importantly, none of the patients reported adverse events associated with the procedure.
Conclusions :
During the current follow-up, progression arrest was observed in 80.1% of patients, with both maximum and minimum curvature remaining unchanged. Visual acuity improved by 1 to 2 lines of vision with optimal correction. Long-term follow-up is essential to adequately assess both the safety and efficacy of the sub-400 protocol.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.