Differences of optic disc appearance between normal tension and high tension glaucoma patients

Abstract

The term glaucoma is used to cover a wide range of diseases, whose main feature is optic neuropathy. According to the level of intraocular pressure (IOP), the open angle glaucoma is arbitrarily divided into high tension glaucoma (HTG) and normal tension glaucoma (NTG). The aim of this study was to investigate the differences of optic disc cup appearance between patients with NTG and HTG. Prospective study included 30 patients (60 eyes) with NTG and 30 patients (60 eyes) with HTG. IOP was measured by Goldmann applanation tonometry. Examination of optic disc head was performed by indirect ophthalmoscopy with Volk 90 D superfield lens through a dilated pupil to observe qualitative and quantitative parameters. Visual fields were examined in all patients with the Octopus program G1, full threshold strategy (Octopus 500 EZ, Interzeag, Switzerland). Vertical form of optic disc cup was present in 11 eyes with NTG (18.3%) and three eyes with HTG (5%) (p < 0.05). A disc with localized tissue loss (polar notching) on the inferior pole was observed in eight eyes with NTG (13.3%) and in one eye with HTG (1.7%) (p < 0.01). Uniformly enlarged, round cup was more frequent in patients with HTG than NTG: 93.3% and 68.3% respectively (p < 0.05). The perceived differences indicate a complex multifactorial nature of glaucoma disease and a possible existence of two pathophysiological ways of optic disc changes within the same basic disease.