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The Heidelberg Retina Tomograph (HRT) is a confocal scanning laser ophthalmoscope. A laser light scans the retina in 24 millisecond sequential scans, starting above the retinal surface, then capturing parallel images at increasing depths. The stacks of images can be combined to create a three-dimensional (3-D) topographic image of the retina. Images are aligned and compared using TruTrack™ software for both individual examinations and for detecting change between examinations. The same technology is used in the HRT Retina Module.

3-D Optic Disc Topography vs. Tomography
When applying the technology to glaucoma, the HRT takes data from a 3-D stack of tomographic images of the optic nerve and retinal nerve fiber layer (RNFL), aligns the images and computes a 3-D topographic map of the surface of the retina. This 3-D topographic map is analyzed for signs of glaucomatous damage and the results are displayed on either a single eye examination report or on an OU examination report.

TruTrack Image Alignment Provides Accuracy in Single Exams
TruTrack™ is proprietary software which aligns images within examinations and between examinations. The software uses anatomical features (such as blood vessel patterns) and other image characteristics to align the images. Good image analysis requires both high quality images (fast scanning) and image alignment. To construct a single examination, the software aligns a stack of individual scans. Each scan is examined for image quality and if any are found to be outside of acceptable quality indices, the scan is discarded from the image set. Three sets of scans are automatically captured at each acquisition, providing data redundancy. The three sets are used to create a final composite image for analysis. Only Heidelberg Engineering offers retinal imaging technology which automatically discards low quality scans.

The Heidelberg Retina Tomographer II is superior to other optic nerve head analyzers for accuracy in 3-dimensional optic nerve head topography. The HRT II uses scanning laser tomography to produce the 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.


The HRT II features automatic image acquisition, sector analysis for early glaucoma detection, and automatic progression analysis. Also, all results are presented in a format which is understood by patients to ensure their compliance. The Heidelberg Retina Tomograph operation software provides a variety of functions to quantitatively describe the three-dimensional properties of the retina and the optic nerve head and to precisely detect and describe topographic changes.

The Heidelberg Retina Tomograph II. Excellent optic nerve head analyzer for accuracy in 3-dimensional optic nerve head topography. The HRT II uses scanning laser tomography to produce the 3-dimensional images.