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Topographic analysis to discriminate glaucomatous from normal optic nerve heads with a confocal scanning laser: new
M Iester1, R De Ferrari, M Zanini
1Department of Neurological and Visual Sciences, Ophthalmology B, University Eye Clinic of Genoa, Italy.
Purpose:
We evaluated the potential ability of a confocal scanning laser ophthalmoscope to differentiate patients with normal visual fields from those with abnormal visual fields with an optic nerve head topographic map.
Patients And Methods:
Twenty normal eyes with normal visual fields, intraocular pressures of less than 22 mm Hg, and no family history of glaucoma and 20 glaucomatous eyes with abnormal visual fields and open angles were selected. Glaucomatous eyes with advanced visual field damage were not included. One eye was chosen randomly from each patient. All eyes were examined with the Heidelberg Retina Tomograph (HRT [Heidelberg Engineering GMBH, Heidelberg, Germany]) and Humphrey Perimeter, program 30-2 (Humphrey Instruments, Inc., San Leandro, CA, USA). Topographic maps were analyzed with different methods based on contour lines, with use of a program able to differentiate glaucomatous from normal optic disks. Sensitivity, specificity, and diagnostic precision were calculated.
Results:
The analysis had a sensitivity, specificity, and diagnostic precision of 80%, 100%, and 90%, respectively.
Conclusion:
With the topographic map data and this technique, the HRT's capacity to differentiate normal optic disks from glaucomatous disks was improved. In addition, with this method, we avoided any subjective observer input in drawing the optic nerve head outline.