Intraocular Lens Power Calculation in High Myopic Eyes with Previous Radial Keratotomy

ABSTRACT

PURPOSE: To elucidate a proper method of intraocular lens (IOL) power calculation in highly myopic eyes with previous radial keratotomy (RK). METHODS: Five post-RK-surgery eyes with pre-RK-surgery myopia over -10.0 diopters (D) were studied retrospectively. The keratometric values obtained via the clinical history method, the contact lens over-refraction method, conventional keratometry, and Orbscan II were compared to the true keratometric value calculated retrospectively using the SRK/T formula. RESULTS: The mean pre-RK-surgery refractive power was -19.35+/-5.86D (-14.50 ~ -29.50D) and cataract surgery was performed on average 16.6 years after RK. The true keratometric value was closest to that estimated by the contact lens over-refraction method in 1 eye and to the flatter keratometric value between Sim K and the 3mm zone mean Pwr obtained with axial keratometric power map of Orbscan II in 4. CONCLUSIONS: The flatter keratometric value between Sim K and the 3mm zone mean Pwr from Orbscan II was closest to the true post-RK-surgery keratometric value of the central cornea.