Functional Magnetic Resonance Imaging in Patients with the Wet Form of Age-Related Macular Degeneration

Abstract

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 × 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.

Keywords: Brain fMRI; ganglion cells; wet AMD.

FIGURE 1

The black and white checkerboard (BW) used for stimulation (size: 25.8 × 16.2 degrees). During the stimulation, the checkerboard picture was alternated with its inversion with a frequency of 2 Hz. Note: Figures 1–6 of this article are available in colour online at www.informahealthcare.com/oph.

FIGURE 2

Usual activation of the visual cortex in control subject (no. 4). Findings on the sagittal (a), coronal (b), and transverse (c) sections are normal.

FIGURE 3

Activation in visual cortex of patient no. 1 (female, age 54, VA RE 0.04, VA LE 0.03). The sagittal (a), coronal (b), and the transverse (c) sections show a significant decrease in fMRI activity.

FIGURE 4

Box plot shows the difference in fMRI activity (expressed in the number of activated voxels) between the control group and the AMD patients.

FIGURE 5

The graph shows the relationship between fMRI activity (expressed in the number of activated voxels) and the average visual acuity of both eyes.

FIGURE 6

Multinomial regression analysis shows decrease of fMRI activation in patients with AMD despite of aging.