Influence of Crosslinking on Astigmatism Vector in Keratoconus: A Vector Analysis

Area of Science:

• Ophthalmology
• Corneal Surgery
• Vision Science

Background:

• Progressive keratoconus requires treatment to halt progression.
• Corneal cross linking (CXL) is a standard treatment for progressive keratoconus.
• Assessing corneal power (Kmax) and astigmatism changes is crucial for monitoring keratoconus progression.

Purpose of the Study:

• To evaluate the suitability of corneal astigmatism for quantifying keratoconus progression and stability post-CXL.
• To compare the accuracy of vector astigmatism analysis versus absolute values in CXL follow-up.
• To determine if astigmatism vector analysis offers a more precise assessment of CXL effectiveness.

Main Methods:

• Retrospective observational study of 74 eyes with progressive keratoconus treated with CXL.
• Minimum follow-up of 12 months, with some up to 5 years.
• Scheimpflug imaging (Pentacam®) used to analyze changes in Kmax and corneal front astigmatism vector.

Main Results:

• Preoperatively, Kmax and astigmatism vector showed a positive correlation, indicating treatment need.
• Postoperatively, both Kmax and astigmatism vector stabilized after 12 months.
• Long-term follow-up (3-5 years) confirmed sustained stabilization of curvature parameters.

Conclusions:

• Vector analysis of astigmatism provides a more precise assessment of CXL effectiveness compared to absolute values.
• Both astigmatism vector and Kmax increase preoperatively and stabilize postoperatively.
• Astigmatism vector should be considered an additional stability factor alongside Kmax due to its impact on visual quality.