Article
Ultrasound biomicroscopy in evidence-based diagnostic of glaucoma
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Published: | September 22, 2004 |
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Outline
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Objective
Several types of glaucoma are caused by structural abnormalities of the anterior segment, in particular in dysgenetic glaucoma and in angle-closure glaucoma, which differentiation leads to different therapies. 50 MHz high resolution images in various types of glaucoma were obtained to analyze the potential of this technique for differential diagnosis.
Methods
After informed consent for ultrasound biomicroscopic imaging 243 eyes of glaucoma patients were examined. A total of 14 different measurement points within anterior chamber were taken and were correlated with the biomicroscopic slit-lamp and gonioscopic findings. 52 volunteers without ocular pathologies were examined as a control group.
Results
The average measurements of patients with open angle glaucoma and with PEX-glaucoma were not significantly different from normal subjects. Patients with pigment dispersion glaucoma and with dysgenetic glaucoma had a significant wider anterior chamber angle when compared to healthy volunteers. Patients with angle-closure glaucoma showed the greatest anatomic variability. In summary the average measurements of all glaucomatous eyes did not differ significantly from those with normal eyes.
Conclusions
Ultrasound biomicroscopy is capable to show the structures of anterior segment that are relevant to glaucoma and provides a system of measurements. However, this technique does not represent a diagnostic tool in case of glaucoma of unclear pathogenesis, because the geometric dimensions in normal eyes do not differ significantly from glaucomatous eyes. Only in case of angle closure - and secondary rubeotic glaucoma with a narrow anterior chamber angle and in case of pigmentary-, dysgenetic-, aphakic - and pseudophacic glaucoma with a wide anterior chamber angle most of the measurements become statistically different. The capacity of ultrasound biomicroscopy to asses the dimensions of posterior chamber become relevant in initial glaucoma diagnosis and improve the differential diagnosis and therapy of several types of glaucoma.