Analysis of HRT Heidelberg Retina Tomograph in High Myopic Patient

ABSTRACT

In high myopic patients with optic disc tilting, reference height is underestimated and many parameters depending on reference height will be changed with previous Heidelberg Retina Tomograph[HRT, under version 1.01].Therefore, care must be taken to classify the patients with tilted optic disc because underestimation of the amount of their cup area and volume may cause faulty decision to normal disc. However, by using "tilted analysis method" in recent HRT program[ver.2.01], we can expect to overcome such problems so, in this study we try to find out how much the HRT results are different between tilted and untilted analysis methods.We evaluated 26 high myopic patients under -6 diopters with tilted optic disc and glaucomatous visual field defects from March 1998 to July 1998. We compared their HRT parameters measured by untilted and then tilted method to each other.The mean reference height was changed from 0.2735 to 0.2892, the cup volume from 0.1961 to 0.1790 and the neural rim volume from 0.3060 to 0.3358 but glaucoma classification, the final conclusion of test, was not changed significantly due to neural rim volume and height variation contour increase with constant cup shape measure. Therefore, although refrence height is lowered and cup volume decreased with HRT[ver.1.01]in high myopic patients, if considering other many parameters, we can interpretate results rightly.