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Erschienen in:
01.04.2006 | Clinical Investigation
Ten-year results: detection of long-term progressive optic disc changes with confocal laser tomography
Erschienen in: Graefe's Archive for Clinical and Experimental Ophthalmology | Ausgabe 4/2006
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Background
The detection of a slowly progressive loss of optic nerve fibres in patients with ocular hypertension is a very important task for confocal laser tomography. We compared changes of the parameters of the Heidelberg Retina Tomograph (HRT) with changes of static visual field measurements.
Methods
Since 1994, patients with ocular hypertension have been monitored prospectively every 6 months with visual field measurements (Octopus 123, dG1x) as well as examinations of the optic disc using the HRT. A progressive excavation of the optic nerve head was defined as a significant increase or decrease of the linear regression over time. We analysed the HRT parameters cup area (CA), cup volume (CV), cup shape measure (CSM), rim volume (RV), retinal nerve fibre thickness (RNFLT) and contour height variation (CHV) each circular and for six different sectors of 109 eyes (60 patients). A glaucomatous visual field defect and therewith the conversion from ocular hypertension (OHT) to open angle glaucoma (OAG) was defined as reproducible defect-cluster >20 dB of two or three single points at the same location.
Results
Nine of 109 eyes converted from OHT to OAG. A significant linear increase of the circular parameters occurred in two (CA), four (CSM), two (CV) and a decrease in three (CHV), two (RV) and four (RNFLT) eyes. The sectoral analysis increased the results of CA and CV in the temporal superior and temporal inferior sectors (ts/ti): five/four (CA), two/three (CV). Cup shape measure showed in the temporal superior, temporal inferior (ti) and nasal inferior (ni) sectors slightly increased hits [five (ts), five (ti), five (ni)].
Conclusions
The linear model for the progression of the optic disc parameters detected only a small amount of the converters. The hit rate could be increased with the sectoral based analysis. Cup shape measure showed the highest rate.