Catching sight of glaucoma with 3D visualisation and fuzzy-based decision support

Homburg 16 November 1999At the Department of Ophthalmology and the Eye Hospital of the University of Saarland in Homburg, a dedicated team of physicians has tried out a novel prototype system to timely detect glaucoma in older patients, as well as to optimise the monitoring process, allowing to measure the progress of the disease. The advanced solution applies high performance computing (HPC) technology, as it has been based on a combination of autostereoscopic 3D visualisation, automated and interactive segmentation, and embedded knowledge based decision support. The system was developed in the Esprit funded project VISPAR, which lasted 14 months from early December 1997 until the end of January 1999.

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For several years now, the Eye University Hospital of Saarland is at the forefront of ophthalmologic expertise and research with its programme for early glaucoma diagnostics. The physicians at the eye clinic are using the Heidelberg Retina Tomograph (HRT), developed by Heidelberg Engineering, a major manufacturer of laser scanning systems for ophthalmoscopy, in order to analyse the topography of the retina surface with the optic nerve head or papilla. This data is delivered in 3D by the HRT and used to characterise the morphology of the papilla as well as its inner excavation. Up till now, doctors had to manually draw the papilla contour, combining the topography image with a reflectivity image.

This procedure resulted in less accurate measurements since the physicians have to rely on two independent colour-coded 2D images to obtain the right spatial impression to quantify each tiny morphological parameter change in the papilla. The slightest detection of morphological degradation can indicate the loss of nerve fibres, causing patients to gradually lose their eyesight. The ophthalmologists have to be able to clearly distinguish between the detection of outliers due to rare individual morphologies or false measurements, and the initial phase of glaucoma. Therefore, scientists at the Dresden University of Technology have designed an autostereoscopic display to replace the less accurate manual papilla contour definition with the realistic computer-aided spatial impression of the topography and reflectivity data into one single 3D view.

The 3D ocular fundus presentation facilitates morphology measurements for the ophthalmologists in Homburg and makes them more easily reproducible for early stage glaucoma diagnosis. Additionally, the VISPAR project, which stands for Visual Papilla Recognition and Glaucoma Diagnosis Support, also dealt with the aspect of monitoring the glaucoma progress in patients and of validating the image quality. Fraunhofer's EADQ Division in Dresden as one of the VISPAR partners designed the embedded knowledge based modules for decision support in glaucoma diagnosis. Starting from a statistical analysis of a large clinical data set, a model based on fuzzy techniques was built into the system to provide the physicians with a sophisticated means for relative progress estimation of the disease.

The clinical evaluation of the VISPAR system at the Eye Hospital in Homburg has proven that interactive 3D visualisation might substantially enhance the doctor's involvement in the treatment of patients, threatened by glaucoma. In turn, the optimised support, enhanced by fuzzy methods, for an accurate decision making in disease monitoring can offer direct benefits for the level of medical care in general. A higher quality of measurements implies more specific and more effective diagnosis. As a result, Dresden Informatik, as the VISPAR project co-ordinator, hopes to avoid redundant or even unnecessary measurements and to reduce a significant and costly workload. This enables the Homburg ophthalmologists to help more patients in the same amount of time. More details are available at the VISPAR home page.


Leslie Versweyveld

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