Glaucoma Diagnosis Advances With The Heidelberg Retinal Tomograph (HRT) and Ocular Coherence Tomography (OCT)

Our practice offers a state-of-the-art computerized laser scanning devices specifically designed to aid in the diagnosis of glaucoma. For decades, precise observation and documentation of the optic nerve head has been essential for the diagnosis and management of glaucoma.

In previous generations eye doctors depended on ophthalmoscopic observations, coloured drawings, and clinical notes to determine whether the nerve had been damaged by glaucoma. The Heidelberg Retina Tomograph uses scanning laser tomography to produce 3-dimensional images, which allow precise measurements of optic nerve head parameters.

This technology is purported by Heidelberg Engineering to differentiate between normal eyes and glaucomatous eyes even before visual field defects are present. It also allows for accurate comparison on follow-up examination

The Ocular Coherence Tomographer (OCT) provides high resolution cross-sectional imaging of ocular tissues.  It can measure retinal nerve fibre layer tissue as will as macula thickness and can be used to study glaucoma as well as macular conditions such as macular degeneration and edema.

The technique is analagous to ultrasound except is uses light (843nm) instead of sound waves to allow exceptionally high resolution.  Reflected light from nerve or retinal tissue and a reference mirror interact to produce an interference pattern which is detected and processed into a signal.  Strong reflections occur at the interface between materials of different refractive indices and from tissues with high scattering coefficients.  Distances between ocular tissues can be measured from the time taken for the light to reflect from the various structures within the eye.  A tomographical image is generated by simultaneously performing and displaying 100 longitudinal adjacent scans.  Image quality can be affected by such things as cataracts but are still obtainable in most situations.