Abstract
Purpose:
Open-angle glaucoma was defined as a neurodegenerative disease, characterized by high intraocular pressure (IOP), progressive retinal cell death, with subsequent visual field loss (Flammer and Drance, 1984). Elevated IOP has been identified as one of the major risk factors for glaucomatous optic nerve damage and current treatment of glaucoma aims to reduce IOP to prevent visual loss (Heijl et al., 2002). However, an adequate IOP control cannot prevent the disease progression in all patients. The aim of the present study was to explore the optic nerve capillaries blood oxygenation in healthy subjects and patients with open-angle glaucoma.
Methods:
The normal blood oxygenation of the optic nerve’s capillaries has been estimated in 35 healthy subjects from a laboratory database. The blood oxygenation of the optic nerve’s capillaries has been also estimated in 16 eyes of 8 glaucoma patients, under treatment with different topical medication, to maintain lower IOP. A non-invasive retinal oximeter, with a multichannel spectroscopy technique has been used to measure the optic nerve’s blood oxygenation (Diaconu 1009). The blood oxygenation has been evaluated from three specific locations from the optic nerve papilla, representing an area of 0.5 mm in diameter. An experimental session consisted of 20 consecutive measurements in an interval of 10 seconds for each investigated area.
Results:
The results from the present study suggest a homogeneous blood oxygenation in the optic nerve capillary area structures of the normal subject. For a 95% confidence interval, the normal optic nerve’s blood oxygenation is in the range, from 59% to 72,75%. The papilla of the glaucomatous subjects could include areas, where the blood oxygenation rate is either lower or higher compared to the normal blood oxygenation values. However the papilla of the optical nerve of four glaucomatous patients participating in the study presents blood oxygenation within the limits of the normal range.
Conclusions:
The present study suggests that the blood oxygenation measurements at the level of the capillary structures in the area of the optical nerve could provide insight into the evolution of glaucoma.
Keywords: 436 blood supply •
550 imaging/image analysis: clinical •
629 optic nerve