HRT for the Diagnosis and Detection of Glaucoma Progression

Confocal scanning laser ophthalmoscopy through the Heidelberg Retina Tomograph (HRT) provides a rapid, safe, noncontact, and noninvasive imaging of the optic disc in three-dimensions, and provides precise detailed information about the optic disc beyond that which the clinical exam can measure. The HRT I was developed for research purposes only and was not used clinically. The HRT II was developed to be user-friendly, more rapid, and was used as an adjunct to clinical examination in the detection and progression of glaucoma. One of the main pitfalls of the HRT II was that it was operator-dependent. The HRT III was developed to be operator-independent. Initially the Moorsfield Regression Analysis provided the analysis of the stereometric optic disc parameters. The Glaucoma Probability Score, given its ease of use, operator-independence, and rapidity of use, soon gained popularity. Numerous studies have compared these two methods of analysis, with the conclusion that the Glaucoma Probability Score provides a higher sensitivity and a lower specificity than the Moorsfield Regression Analysis, which may indicate that it has potential as a screening test for glaucoma. However, there is no consensus on the use of the Glaucoma Probability Score as a screening test for glaucoma. While HRT data may be useful as a clinical adjunct in the screening and diagnosis of glaucoma, it should ultimately only be used to support clinical examination.