Contrast sensitivity and higher-order aberrations in Keratoconus subjects

Area of Science:

• Ophthalmology
• Corneal Diseases
• Visual Optics

Background:

• Keratoconus is a progressive corneal disease affecting visual quality.
• Higher-order aberrations (HOA) and contrast sensitivity (CS) are key indicators of visual function.
• Understanding their relationship in early-stage keratoconus is crucial for diagnosis and management.

Purpose of the Study:

• To investigate the association between contrast sensitivity and higher-order aberrations in mild and subclinical keratoconus.
• To compare visual function parameters between keratoconus patients with good visual acuity and healthy controls.

Main Methods:

• Corneal topography, tomography, and higher-order aberrations (HOA) were measured in keratoconus and control groups.
• Contrast sensitivity was assessed using psychophysical Gabor patches at 6, 9, and 12 cycles per degree.
• Spearman correlation analysis was employed to determine the relationship between HOA and contrast sensitivity.

Main Results:

• Keratoconus subjects exhibited significantly higher HOA and lower contrast sensitivity across all spatial frequencies compared to controls.
• A significant negative correlation was found between most HOA and contrast sensitivity in the keratoconus group.
• Even in keratoconus patients with 0.00 LogMar visual acuity, reduced contrast sensitivity and elevated HOA were observed.

Conclusions:

• Mild and subclinical keratoconus, even with good visual acuity, are characterized by reduced contrast sensitivity and increased higher-order aberrations.
• The inverse correlation between HOA and contrast sensitivity highlights HOA as a primary factor diminishing vision quality in early keratoconus.