Defining subclinical keratoconus using corneal first-surface higher-order aberrations

Area of Science:

• Ophthalmology
• Optometry
• Corneal Science

Background:

• Keratoconus (KC) is a progressive corneal ectasia.
• Early detection of KC is crucial for timely intervention.
• Fellow eyes of KC patients may harbor subclinical disease.

Purpose of the Study:

• To characterize corneal higher-order wavefront aberrations in clinically inconspicuous fellow eyes of early KC patients.
• To compare these aberrations with those in early KC eyes and healthy controls.
• To assess the diagnostic potential of specific aberration metrics.

Main Methods:

• Prospective comparative case series at a university eye hospital.
• Included 23 early KC eyes, 10 fellow eyes, and 127 healthy controls.
• Analyzed first-surface aberrations using Zernike decomposition and discriminant analysis, evaluating receiver-operating characteristic (ROC) curves.

Main Results:

• Significant differences in Zernike coefficients and aberration metrics were found between early KC eyes and controls.
• Fellow eyes showed significant differences from controls in specific coefficients (Z(3)(-1), Z(5)(-1)).
• Discriminant analysis (D(23)) and Z(3)(-1) effectively differentiated fellow eyes from controls (Area Under Curve [AUC] > 0.96).

Conclusions:

• Clinically normal fellow eyes of early KC patients exhibit distinct first-surface corneal aberrations.
• These aberrations suggest the presence of subclinical keratoconus in these eyes.
• Wavefront aberration analysis can aid in identifying eyes at risk for KC progression.