The Comparative Study of Applanation and Optical Coherence Biometry Methods for the Intraocular Lens Power Calculation

Abstract

AIM: To compare applanation biometry (A-Scan) and optical coherence biometry newline(AL-Scan) methods for IOL power calculation based on post operative refractive newlineoutcome. newlineRATIONALE: Cataract surgery has been considered as one of the refractive newlinesurgeries as providing post-operative unaided perfect visual acuity. So accurate newlinebiometry and power precision of IOLs have greater importance. newlineOBJECTIVE: To compare preoperative Axial Length measurement among two newlinegroups, to determine the limitations of both the types of biometries and to compare newlineapplanation biometry and optical coherence biometry methods for IOL power newlinecalculation based on post operative refractive results. newlineSTUDY AREA: OPD of the department of ophthalmology, Dr. Sushila Tewari newlineGovernment Hospital and Medical College, Haldwani (Tertiary Care Center in Kumaon newlineregion of Uttarakhand). newlineSTUDY POPULATION: OPD case selection, male and female adults both of 40 to newline70 of age group, urban and rural type socio-economic status. newlineSAMPLE SIZE: Assuming Cohen s effect size, sample is taken about 400 (200 per newlinegroup). newlineSTUDY DESIGN: Prospective and Interventional Randomized Comparative Study. newlineTIME FRAME: Three Years. newlineMETHODS: Keratometry by AL-Scan, Biometry by A-Scan and AL-Scan, IOL newlinepower by both the biometries. newlineDATA COLLECTION TECHNIQUE: By the measurement of parameters. newlineOUTCOME MEASURES: Primary outcome measure is post operative refractive newlinevalue in the form of spherical equivalent in Diopters. The secondary outcomes are newlinecorneal power in Diopter, Axial Length in mm. and IOL Power in Diopter. newlineIII newlineSTATISTICAL ANALYSIS: The data will be entered in MS EXCEL spreadsheet newlineand analyzed with SPSS software (version 21) and p-value of lt0.05 will be newlineconsidered statistically significant. newlineKEY WORDS: A-scan, AL-Scan, Keratometry, A.L., IOL Power, Sph. Eq. newline