Interobserver and intraobserver reliability of a classification scheme forcorneal topographic patterns

Aims - To determine the interobserver and the intraobserver reliability of a published classification scheme for corneal topography in normal subjects using the absolute scale. Method - A prospective observational study was done in which 195 TMS-1 corn eal topography maps in the absolute scale were independently classified twi ce by three classifiers - a cornea fellow, an ophthalmic technician, and an optometrist. From these observations the interobserver reliability for eac h category and the intraobserver reliability for each observer were determi ned in terms of the median weighted kappa statistic for each category and f or each observer. Results - For interobserver reliability, the median weighted kappa statisti c for each category varied from 0.72 to 0.97 and for intraobserver reliabil ity the range was 0.79 to 0.98. Conclusion - This classification scheme is extremely robust and even in the hands of less experienced observers with minimal training it can be relied upon to provide consistent results.