FMRI was measured by the BOLD method using a gradient-echo EPI sequence with the following parameters: TE=30 ms, TR=3 s, flip angle 90°. The measured volume consisted of 39 continual slices of 2 mm in thickness and the size of the measured voxel (spatial resolution) was 2 x 2 x 2 mm (FOV=208 x 208 mm, matrix 104 x 104, reconstruction matrix 128 x 128, SENSE factor of 1.8). FMRI was performed in all the subjects. An alternation of a black and white checkerboard (Figure 1) was shown to the subjects during the fMRI acquisition. The alternation was in the form of colour inversion with the frequency of 2 Hz. During the resting phase, the subjects were shown a static cross hair placed in the middle of the visual field. Each measurement consisted of a five30-second blocks of active phase periods (10 dynamic scans) and five resting periods of the same length. Altogether, each measurement consisted of 100 dynamic scans and lasted 5 minutes. FMRI assessment was performed using SPM8 software. During the pre-processing, the data were motion corrected (realigned), corrected for slice timing, smoothed the Gauss filter with FWHM of 6 x 6 x 6 mm and finally normalized into the MNI_152 space. The subject-level statistic was created using a general linear model with the canonical hemodynamic response function (HRF) applied to the stimulation

Aim. The objective of our work was to determine whether there is a difference in fMRI activation between patients with high tension glaucoma (HTG) and those with normal tension glaucoma (NTG). Method. The sample consisted of eight patients with different stages of high tension glaucoma (3 females aged 41-65 and 5 males aged 40-73 years) and eight patients, also with different stages of normal tension glaucoma (6 females aged 53-70 and 2 males aged 40-52 years). The control group consisted of eight healthy subjects (3 females aged 23-46 and 5 males aged 23-65 years). All underwent complete ophthalmological examination, including visual field, colour vision, and electrophysiological functions. The results were compared with fMRI images after stimulation with black/white (BW) and blue/yellow (BY) checkerboard and then statistically processed. Results. The authors analyzed the results of published studies on high tension versus normal tension glaucoma in the images obtained by fMRI. They concluded on the basis of electrophysiological examinations that in high tension glaucoma, damage of the whole visual pathway occurs, starting from retinal ganglion cells up to the visual cortex. In normal tension glaucoma the response of ganglion cells is relatively normal. The pathology is found mainly in the visual pathway. For this reason, the authors carried out fMRI examinations in high tension glaucoma patients and patients with normal tension glaucoma. They found that advancing stages of high tension glaucoma cause progression of fMRI activity decrease. These relations were not observed in normal tension glaucoma cases. Similarly, in high tension glaucoma on fMRI examination to yellow/blue stimuli, the fMRI activity decrease was found to be greater than that to black/white stimulation. No similar effect was observed in normal tension glaucoma. Conclusion. Normal tension glaucoma is, from the etiopathogenetical view, a different disease than high tension glaucoma.

The study is designed to determine the relationship between the progress of the wet form of age-related macular degeneration and the activity of the visual cortex examined using functional magnetic resonance imaging. Ten patients with the wet form of age-related macular degeneration (9 female and 1 male) with a mean age of 74.7 years (58-85 years) at various stages of bilateral involvement of the disease were included. Patients did not suffer from any other ocular nor neurological disease. All the patients underwent functional magnetic resonance imaging examinations with stimulation of both eyes using a black-and-white checkerboard of size 25.8 Â 16.2 degrees. The group was compared with a group of healthy subjects with an average age of 54.1 years (45-65 years). For statistical evaluation, the Mann-Whitney U test was used. Comparing the extent of visual cortex activations we found a statistically significant difference between both the groups (p = 0.0247). However, the dependence of functional magnetic resonance imaging activity on visual acuity was not statistically significant (p = 0.223). We conclude that in patients with the wet form of age-related macular degeneration, lower functional magnetic resonance imaging activity of the visual cortex was found compared with the control group of healthy subjects. Dependence of functional magnetic resonance imaging activity on visual acuity was not statistically significant.

Objective: To prove potential difference between black/white and yellow/blue stimulation when using functional magnetic resonance imaging (fMRI) examination in advanced stages of glaucoma disease. Methods and materials: The authors examined eight patients with various stages of high-tension glaucoma using functional magnetic resonance imaging (fMRI). The group was compared to a group of eight healthy persons. Measurements were performed on the Philips Achieva 3T TX MR system using the BOLD method. Optical stimulation was provided by black/white and yellow/blue checkered patterns alternated with their negatives with a frequency of 2 Hz. Each measurement consisted of a sequence with five 30-second periods of active phase and five resting periods of the same length. The obtained data were processed by SPM8 software and GLM. The difference in the number of activated voxels when using the black/white or yellow/blue stimulations was tested by a t-test. Statistical maps of BW>YB and BWYB difference between the control group and the patients differed by the statistically significant 1606 voxels (p=0.039), no difference was found for BW

Introduction: Functional and structural changes of the central nervous system corresponding to high tension glaucoma (HTG) and normal tension glaucoma (NTG) were studied. Methods:In four patient groups, 80 eyes in 40 patients were examined. First group of 30 patients had three types of HTG: 10 with primary open angle glaucoma (POAG), 10 with pigmentary glaucoma (PG) and 10 of the monitored patients had pseudoexfoliative glaucoma (PEXG). The last patient group consisted of 10 patients with NTG. Comparison of the visual field, GDx, macular volume, PERG and PVEP was performed with the control group consisting of 40 eyes in 20 healthy subjects of comparable age and refraction.From the group of patients with HTG and NTG, we further studied functional brain changes using functional magnetic resonance imaging (fMRI). We examined 9 patients with HTG in different stages and 8 NTG patients (stage initial to medium) using fMRI with optical stimulation. Brain activations in both patient groups were compared with group of 8 healthy controls.Moreover, the size of lateral geniculate nucleus in these patients with HTG and different stages of NTG was compared.Results: Patients with PG had the highest degree of damage of the optic pathway. In the NTG, however, the ganglion cell layer was relatively normal but significant pathological changes were found in the optic pathway. Restriction in visual cortex activation indicates that the progression of high tension glaucoma corresponded to the functional changes in the cerebral cortex. Similar behavior was not observed in patients with NTG. We also proved the reduction of lateral geniculate nucleus (LGN) in both HTG and NTG. Conclusion:We conclude that in HTG of varied etiology, the damage occurs in the entire optic pathway. Based on our experience as well the medical literature, we think that HTG and NTG are different diseases and therefore their approach should be different.