[Significance of raised intraocular pressure in glaucomatous visual field defects. A clinical study]

1. 300 eyes of 300 patients with primary open angle glaucoma (POAG) were examined with program 31 of the Octopus perimeter 201 and the amount of visual field loss (total loss) was quantified with program Delta. The total loss was correlated to the height of the maximum intraocular pressure (IOP max). There was no correlation in the interindividual comparison between IOP max and total loss. This shows the influence of IOP independent risk factors in POAG. 2. In an intraindividual comparison 108 eyes of 54 patients with POAG were examined under the question: Have eyes with the four times higher amount of visual field loss in one eye compared to the other, a significant higher IOP max in the eye with the more severe damage. The intraindividual comparison excludes cardiovascular risk factors, because they affect both eyes. So the difference in IOP can show better the damaging influence of IOP: Eyes with the higher amount of visual field loss showed a significant higher IOP max. This shows the impact of the elevated IOP is a risk factor in POAG. 3. 300 eyes of 300 patients with POAG were further examined under the question, whether the relation between the mean loss per test point in the upper half of the visual field in comparison to the mean loss per test point in the lower half of the visual field is different at different IOP max levels. 162 eyes with an IOP max of less than 30 mmHg and 75 eyes with an IOP max of 30 up to 36 mmHg and 63 eyes with IOP max of 37 and more mmHg were evaluated and the 3 groups were compared. With an increasing height of IOP max an increasing equal distribution of the visual field loss in upper and lower visual field half was found. High IOP results in a diffuse nerve fibre damage and more IOP-unindependent risk factors result in localized visual field damage. So there are at least two pathomechanisms in POAG.