Change in corneal shape and corneal wave-front aberrations with accommodation

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Accommodation is the eye's ability to change focus from distant to near objects.
• Corneal topography and wave-front aberrations are critical for understanding visual quality.
• Previous research has explored changes in the lens during accommodation, but corneal changes are less understood.

Purpose of the Study:

• To investigate how the cornea's curvature and wave-front aberrations change during accommodation.
• To quantify alterations in corneal shape parameters with varying visual demands.

Main Methods:

• Corneal topography was used to measure corneal curvature in 12 young adults.
• Measurements were taken while subjects fixated at far (4.0 m) and near (0.2 m) distances.
• Convergence was controlled to isolate the effects of accommodation.

Main Results:

• A significant increase in mean corneal radius at the vertex and shape parameter was observed during near viewing compared to far viewing.
• No significant group change in the root mean square of wave-front aberrations was detected, but individual variations were noted.
• Significant mean changes in x-axis coma and spherical aberration were found within the group.

Conclusions:

• Corneal accommodation involves an increase in peripheral curvature with a concurrent flattening at the corneal vertex.
• These corneal shape changes contribute to the overall accommodative response of the eye.
• Individual variability in wave-front aberration changes suggests personalized optical responses to accommodation.