Definitions for Keratoconus Progression and Their Impact on Clinical Practice

Area of Science:

• Ophthalmology
• Corneal Diseases
• Vision Science

Background:

• Keratoconus (KC) progression criteria lack consensus, leading to potential overtreatment.
• Establishing reliable methods to identify progressive KC is essential for appropriate patient management.

Purpose of the Study:

• To evaluate the performance of various keratoconus progression criteria.
• To compare these criteria against established clinical knowledge of KC evolution.

Main Methods:

• Retrospective analysis of 906 keratoconus patients' data.
• Assessed progression criteria based on keratometry (K MAX), front astigmatism (A F), pachymetry (P MIN), and ABCD progression display.
• Evaluated individual and population consistency of progression detection.

Main Results:

• Single progression criteria yielded high rates of eyes flagged as progressive (R PROG).
• Combining K MAX and P MIN showed better population consistency than K MAX and A F.
• Alternative criteria (K 2F and R mB) demonstrated superior consistency and lower variability.
• Adjusting the ABCD display with wider confidence intervals reduced R PROG to 27.9%.

Conclusions:

• Current progression criteria may lead to overtreatment due to high R PROG values.
• Combining variables or widening margins in progression displays improves consistency.
• Revised criteria bring R PROG closer to observed clinical progression rates (20-30%).