97th DOG Annual Meeting 1999
GLAUCOMATOUS VISUAL FIELD DEFECTS
IN STANDARD AND REDUCED LUMINANCE LEVEL
A. Castro*, H. Krastel+, I. Eggers+, A. Scheuerle
Background: In reduced illumination even normal observers experience a reduction of contrast- and light increment sensitivity. Impaired dark adaptation in glaucoma (AMMANN, JAYLE) shows up in perimetry if visual field recordings with standard and with reduced luminance level are compared.
Methods and Patients: A Tbingen automatic perimeter is modified by neutral density filter and diaphragm so as to reduce both stimulus and cupola luminance by 1.3 log units. Hereby, the relation in luminance of stimulus and cupola is preserved. 30 degrees threshold fields are obtained with standard and reduced luminance. Furthermore, mesopic vision is evaluated by the mesoptometer. Optic nerve head cupping is estimated by biomicroscopy (CDR) and direct ophthalmoscopy (dpt) and it is measured by HRT laser scan tomography. 19 normal observers (aged 32 - 57) and 27 patients with chronic glaucoma (aged 34 - 62) are examined.
Results: Light increment sensitivity worsens with reduction of luminance level and with increase of optic nerve cupping. Loss of light increment sensitivity in reduced luminance is significantly (p < 0,05) more pronounced in the sample of patients with chronic glaucoma than in the reference sample of normal observers.
Conclusion: Glaucomatous impairment of dark adaptation leads to worsening of light increment sensitivity throughout the visual field, as evidenced by comparing perimetric recordings obtained with standard and with reduced luminance. The combined demand on dark adaptation and visual field accounts for more pronounced defects than standard perimetry alone. The results are of significance in clinical diagnosis and in patient guidance, with particular concern to traffic safety.
Dept. of Ophthalmology, University of Heidelberg (Leader Prof. H.E. Vlcker), INF 400, D-69120 Heidelberg, with cooperation by Dora Berger und Helene Jurk-Rempel. Supported by Oculus, Inc., by a DFG grant (+Kr 584/2 - 3) and by the KAAD *.