Corneal higher-order aberration changes after accelerated cross-linking for keratoconus.

Area of Science:

• Ophthalmology
• Corneal Surgery
• Vision Science

Background:

• Keratoconus (KC) is a progressive corneal ectasia leading to visual impairment.
• Corneal higher-order aberrations (HOAs) significantly affect visual quality in KC patients.
• Epithelium-off accelerated corneal cross-linking (A-CXL) is a therapeutic option for KC.

Purpose of the Study:

• To assess changes in corneal HOAs after A-CXL in keratoconus patients.
• To evaluate the impact of A-CXL on uncorrected (UDVA) and corrected distance visual acuity (CDVA).
• To determine the relationship between specific HOA changes and visual acuity outcomes.

Main Methods:

• Retrospective case series of 32 eyes from 24 keratoconus patients undergoing A-CXL.
• A-CXL protocol: 10 mW/cm² for 9 minutes, delivering a total dose of 5.4 J/cm².
• Analysis of anterior corneal HOAs (total HOAs, trefoil, secondary trefoil, coma, secondary coma, secondary astigmatism, spherical aberrations) using Scheimpflug-Placido topography at baseline and 12 months.
• Multivariate analysis to assess the independent effect of HOA subtypes on UDVA and CDVA changes.

Main Results:

• Significant improvements in UDVA (-0.13 ± 0.19 LogMAR) and CDVA (-0.08 ± 0.11 LogMAR) were observed at 12 months post-A-CXL (P < 0.001 for both).
• Mean preoperative HOAs including trefoil, secondary trefoil, secondary coma, and secondary astigmatism showed significant reductions at one year (P < 0.05 for all).
• No independent association was found between overall HOA changes and UDVA improvement. However, a reduction in secondary coma was significantly associated with CDVA improvement (P = 0.048).

Conclusions:

• A 9-minute A-CXL protocol is effective in reducing corneal HOAs and improving visual acuity in progressive keratoconus patients at 12-month follow-up.
• The reduction in secondary coma aberration demonstrated a statistically significant and independent positive effect on corrected distance visual acuity.