Predicting corneal refractive power changes after orthokeratology.

Area of Science:

• Ophthalmology
• Optometry
• Corneal Physiology

Background:

• Orthokeratology (OK) is a method for correcting myopia.
• Understanding corneal refractive power (CRP) changes during OK is crucial for myopia management.
• The relationship between central and peripheral refractive changes requires further characterization.

Purpose of the Study:

• To characterize corneal refractive power (CRP) changes along the principal corneal meridians during orthokeratology (OK).
• To investigate the central-paracentral (CPC) power ratio as an indicator of peripheral defocus after OK lens wear.

Main Methods:

• Nineteen myopic participants underwent OK lens fitting.
• Corneal topography was captured before and after 14 nights of OK lens wear.
• CRP was calculated across the central 8 mm cornea; CPC power ratio was determined.

Main Results:

• Significant CRP reduction occurred in the central 4 mm cornea (p < 0.001), except superiorly at 2 mm.
• CRP increased in paracentral zones nasally, superiorly, and temporally (p < 0.05).
• No significant change in inferior CRP, except a decrease at 2.5 mm (p < 0.001).

Conclusions:

• Orthokeratology induces significant CRP changes along horizontal and vertical corneal meridians.
• Peripheral retinal myopia may exceed twice the central corneal power reduction after OK.
• CPC power ratios offer a potential method for estimating peripheral defocus post-OK.