Corneal collagen cross-linking for treating keratoconus

Area of Science:

• Ophthalmology
• Corneal diseases
• Vision science

Background:

• Keratoconus, affecting 1 in 2000 people, causes progressive corneal curvature increase and vision loss, impacting quality of life.
• Collagen cross-linking (CXL) using ultraviolet A (UVA) light and riboflavin is an emerging treatment to potentially halt early-stage keratoconus progression.

Purpose of the Study:

• To evaluate the efficacy and safety of CXL in halting keratoconus progression compared to no treatment.
• To assess the available evidence from randomized controlled trials (RCTs) on CXL for keratoconus management.

Main Methods:

• A systematic review of RCTs comparing CXL (UVA/riboflavin) with no treatment for keratoconus.
• Searched multiple databases (CENTRAL, MEDLINE, EMBASE, etc.) without date or language restrictions.
• Primary outcomes included increase in maximum keratometry (≥1.5 D) and visual acuity deterioration (≥0.2 logMAR) at 12 months.

Main Results:

• Three RCTs with 219 eyes (119 CXL, 100 control) were included; all had high risk of bias.
• Limited evidence suggests CXL may reduce keratometry increase (RR 0.12, 95% CI 0.01-2.00 at 12 months) and progression (RR 0.03, 95% CI 0.00-0.43 at 36 months).
• Treated eyes showed reduced corneal steepness (MD -1.92 D) and improved uncorrected visual acuity (MD -0.20 logMAR) at 12 months; adverse effects were mostly transient and low-grade.

Conclusions:

• Current evidence for CXL in keratoconus management is limited due to a lack of high-quality RCTs.
• Further rigorous research is necessary to definitively establish the efficacy and safety of CXL for keratoconus.