Aim: To make a factor analysis of some basic criteria for diagnosis of primary open-angle glaucoma regarding their grouping into separate factors.
Material and methods: We performed perimetry with 30-degree threshold grid program of Dicon TKS 4000 automated perimeter, digital planimetry of the optic disc with Topcon ImageNet1224 system and intraocular pressure measurement on a group of 100 patients with primary open-angle glaucoma (mean age - 64.5 ± 8.8 years).
Results: The application of factor (data reduction) analysis yielded three factors (dimensions), that accounted for 84.2% of the total variance of the data. The first factor includes visual field changes, expressed by mean deviation of the whole field, mean deviation of the nasal hemifield and the Advanced glaucoma intervention study score and accounts for 36.5% of the changes. The second factor groups the optic disk changes expressed by vertical, horizontal and area cup-disk ratio and accounts for 35% of the changes. The third factor groups patient age and intraocular pressure accounts for 12.7% of the changes.
Conclusion: Visual field loss, optic disc changes and intraocular pressure are three different dimensions in the diagnosis of the primary open-angle glaucoma which are not interchangeable. They are essential for the clinical evaluation of every patient.