Inter-Ocular Asymmetry in Anterior Corneal Aberrations Using Placido Disk-Based Topography

Area of Science:

• Ophthalmology
• Optometry
• Corneal topography

Background:

• Inter-ocular asymmetry in anterior corneal high-order aberrations (HOAs) has not been previously investigated.
• Understanding HOA asymmetry is crucial for accurate refractive error assessment.

Purpose of the Study:

• To investigate the normal range of inter-ocular asymmetry in corneal HOAs.
• To explore the relationship between anterior corneal HOA parameters and refractive error.

Main Methods:

• 257 subjects (myopia, hypermetropia, emmetropia) underwent HOA measurement using a Placido disk-based corneal topographer.
• Inter-ocular asymmetry was quantified by root mean square (RMS) values at 3, 5, and 7 mm pupil sizes.
• Specific aberrations (trefoil, comma, spherical) were recorded for a 5 mm pupil.

Main Results:

• Hypermetropes showed the highest inter-ocular asymmetry in RMS values, spherical aberrations, and higher-order trefoil.
• Myopic groups exhibited the highest inter-ocular asymmetry in oblique trefoil aberrations.
• Emmetropes had the highest inter-ocular asymmetry in horizontal coma values, while hypermetropes had the lowest.

Conclusions:

• This is the first study to examine inter-ocular differences in anterior corneal HOAs.
• Results provide a basis for establishing normal values of HOA inter-ocular asymmetry.
• These normal values may guide clinicians in managing patient refractive errors.