Intraocular Lens Power Calculation in the Absence of Pre-PRK Data in Moderate Myopic Eyes

ABSTRACT

PURPOSE: To evaluate the correlation between the conventional method and the clinical history method for intraocular lens power calculation for cataract surgery in eyes with previous photorefractive keratectomy in the absence of pre-PRK data. METHODS: The medical records of 38 eyes in 23 patients who had been treated with PRK for myopia and were followed up for more than 1 year were reviewed. The IOL powers by conventional method using post-PRK keratometric value and by clinical history method were compared. RESULTS: The mean values of IOL powers by conventional method, and by clinical history method were +20.58 +/- 1.10D (range, +16.37~+22.80D) and +21.06 +/- 0.85D (range, +18.85~+22.8D), respectively. The following equation describes the regular relationship between the two METHODS: IOLCHM (clinical history method)= 0.683*IOLCM (conventional method) +7.005 (r=0.878, p<.01). When the IOL powers by conventional method were applied to this equation, the mean difference of value between the IOL powers calculated from this equation and those of the clinical history method was?0.01 +/- 0.41D (range, -0.99~+0.76D). CONCLUSIONS: This equation will be helpful to calculate the IOL power for cataract surgery in eyes with previous PRK in the absence of pre-PRK data.