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Abstract #6041 Published in IGR 2-2
Synopsis of different sensory examinations in early glaucoma diagnosis
Korth M; Jünemann AGM; Horn FK; Bergua A; Cursiefen C; Velten I; Budde WM; Wisse M; Martus PKlinische Monatsblätter für Augenheilkunde 2000; 216: 360-368
BACKGROUND: Of the three glaucoma-defining criteria, intraocular pressure, optic-nerve damage, and visual field damage, the latter is a late symptom. Therefore, in order to improve early sensory diagnosis, new tests are necessary. It is the aim of the present paper to test new sensory methods, to rank them in order of sensitivity, and to base them on possible pathophysiological mechanisms. PATIENTS AND METHODS: The tests were carried out on subjects on the Erlangen glaucoma registry: normals, patients with ocular hypertension, and patients with open-angle glaucoma without or with field defects. The tests are designed to preferentially probe the function of different groups of ganglion cells. PSYCHOPHYSICAL METHODS: Temporal contrast sensitivity (CS) in a ganzfeld as 'Erlangen flicker test' and spatio-temporal contrast sensitivity to test Magno-cell function. ELECTROPHYSIOLOGICAL METHODS: Pattern-reversal electroretinogram (PR-ERG) with a luminance contrast pattern to test Magno-cell function, color-contrast pattern electroretinogram (CC-ERG) for Parvo-cell function, and blue-on-yellow visual evoked potential (BY-VEP) to test the 'blue-sensitive' pathway. RESULTS: The most sensitive test is temporal CS, which is significantly reduced in OHT (p < 0.01). Spatio-temporal CS is reduced in perimetric stages (p < 0.01). BY-VEP is altered in the preperimetric stage (p < 0.01), PR-ERG in perimetric stages (p < 0.01). CC-ERG is reduced at even later stages. These results are in agreement with the hypothesis that tests selective for non-redundant neurons are of early diagnostic value. Multivariate analyses increase the early diagnostic value when different functions are tested in combination. CONCLUSIONS: When a particular test is tailored to the the special needs of certain groups of ganglion cells, sensory defects can be observed before the occurrence of optic-nerve damage (OHT). The most sensitive psychophysical test is the 'Erlangen flicker test' which is a screening test selective for M cells. The most sensitive electrophysiological test is BY-VEP testing the blue-sensitive ganglion cells. LA: German
Dr. M.J. Korth, Augenklinik mit Poliklinik, Universität Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen, Germany
Classification:
6.6 Visual field examination and other visual function tests (Part of: 6 Clinical examination methods)
6.7 Electro-ophthalmodiagnosis (Part of: 6 Clinical examination methods)
