Quantitative pupillometry of relative afferent defects in glaucoma.
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Biomedical subjects
Publications and source records attributed to F M Zäch.
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Optic nerve damage is associated with impairment of psychophysical functions. We measured dark adaptation in 21 eyes of 14 normal subjects, 35 eyes of 19 patients with primary open-angle glaucoma, and 7 eyes of 4 patients with nonglaucomatous descending optic nerve atrophy. In the normal subjects light thresholds and time of the shoulder in the dark adaptation curve increased significantly with age. In eyes with glaucomatous or nonglaucomatous optic nerve damage light sensitivity was lower than in normal eyes of age-matched control groups. Rod light sensitivity was significantly (P less than 0.05) correlated with neuroretinal rim loss, parapapillary chorioretinal atrophy, and relative afferent pupillary defects. We conclude that velocity and degree of dark adaptation decrease with increasing age. Patients with glaucomatous and nonglaucomatous optic nerve atrophy show decreased light sensitivity especially in the rod part of dark adaptation worsening with advancing optic nerve damage.
Glaucomatous optic nerve atrophy is associated with morphological and psychophysical changes. Using Roth's Besancon anomalometer, the Farnsworth 100 hue test and Nagel's anomaloscope, we examined color vision in 86 eyes of 51 patients suffering from chronic open-angle glaucoma and 57 eyes of 41 normal subjects. In the normal control group, blue und green sensitivity decreased and, accordingly, the anomaly quotient tested with Nagel's anomaloscope increased significantly (p less than 0.00001) with age. If the glaucoma and control groups were matched for age, refractive error and central visual acuity, decreasing blue sensitivity significantly (p less than 0.05) correlated with diminished visibility of the retinal nerve fiber bundles, a higher morphological glaucoma stage and larger perimetric defects. The presence and depth of localized defects of the retinal nerve fiber layer were not significantly different in glaucoma subgroups with lower and higher blue sensitivity, respectively, when the subgroups were matched for age, refractive error and visual acuity. No papillomorphologic marker for the cyanodyschromatopsia was detected. Red-green color vision was not significantly different between the normal and glaucoma eyes. Testing of blue color vision as an additional method is useful in the differential diagnosis of beginning glaucomatous optic nerve damage in patients with clear optic media and lack of macular changes.
Using planimetric analysis of stereoscopic optic disk photographs, we studied 21 optic nerve heads of 11 subjects who shared the common feature of optic cups that were larger than the mean + 2 S.D. within the normal population. A comparison of these findings to those of 571 normal optic disks and 706 optic nerve heads in eyes with chronic primary open-angle glaucoma showed the following morphologic characteristics: (1) abnormally large optic disk area (mean +/- S.D., 4.49 +/- 0.56 mm2), (2) large cup/disk ratios with the horizontal ratio (0.78 +/- 0.03) significantly (P less than .001) larger that the vertical (0.71 +/- 0.03), (3) increased incidence of cilioretinal arteries, (4) normal neuroretinal rim area (2.06 +/- 0.35 mm2), (5) normal neuroretinal rim configuration, inferiorly (0.43 +/- 0.08 mm) broader (P less than .001, Wilcoxon test) than superiorly (0.33 +/- 0.06 mm), smallest (P less than .0001) temporally (0.20 +/- 0.04 mm), (6) normal form of zone alpha (irregular hypopigmentation and hyperpigmentation) of the parapapillary chorioretinal atrophy with its widest extension in the temporal horizontal area, (7) no zone beta (visible large choroidal vessels and sclera), (8) normal caliber of the parapapillary retinal vessels, and (9) normal parapillary retinal nerve fiber layer. These characteristics are helpful in the differentiation of primary and secondary large cups.