Journal of Clinical and Experimental Ophthalmology
Open Access

Abstract

Changes in the Visual Cortex in Patients with Normotensive Glaucoma

Jan Lešták, Jaroslav Tintěra, Lukáš Ettler, Elena Nutterová and Pavel Rozsíval

Objective: To show whether there is a correlation between visual field changes in normotensive glaucoma and changes in functional magnetic resonance of the visual cortex.
Methods and subjects: The authors examined eight normotensive glaucoma patients (stage initial to medium) by means of functional magnetic resonance imaging (fMRI). Measurements were performed on a Philips Achieva 3T TX MR system using the BOLD method. For visual stimulation, a black and white checkerboard with an alternating negativity frequency of 2 Hz was used. Each measurement consisted of a block scheme with 5 intervals of an active phase lasting 30s followed by 5 resting intervals of equal duration. The measured data were processed on SPM software.
A comprehensive ophthalmological examination was supplemented by an examination of the visual field by means of a fast threshold program. The sum of sensitivity in the field of vision homolateral halves (range 0 to 22 degrees) was compared with a range of fMRI activity contra lateral visual cortex. Data collected from the patients were compared with a group of eight healthy controls.
Results: The collected data was subjected to statistical analysis (nonparametric Spearman’s Rank Correlation Coefficient) which showed a weak indirect correlation between changes in the field of vision and changes in the visual cortex. R=-0,270 (p=0,558), R=-0,071 (p=0,879) respectively.
Conclusion: The authors demonstrated that in the patients with normotensive glaucoma there are no corresponding functional changes in the cerebral cortex, unlike hypertensive glaucoma where the advanced stage of glaucoma changes was associated with lower activation of the visual cortex. They assume that normotensive glaucoma has different pathogenetic behavior than hypertensive glaucoma.