Symmetry of retinal vessel arborisation in normal and amblyopic eyes

Arborisation of retinal vessels might be influenced by the physiological activity of the retina. It seems that the pattern of retinal vessels is an obvious object for fractal analysis. The fractal dimension of normal retinas was therefore used by us as a control value for comparison with the values collected from patients with amblyopia in one eye connected with strabismus and normal vision in the other.

The 'box-counting method' was used for calculation of self-similarity dimension in 54 control patients, i.e. comparing 54 left retinas with 54 right ones. Statistical analysis was performed for these groups. This value was therefore used as a control for comparison with the values of fractal dimensions measured in patients with amblyopia connected with strabismus in one eye and normal vision in the other. The retinas of 30 patients with strabismus in one eye and of 1 patient with strabismus in both eyes were analysed.

The measurements performed on digitised photos of the retinas of these patients proved statistically significant differences between the control group and the fractal dimensions for the arborisation of retinal vessels in the eyes of patients with normal vision as well as differences in comparison with the retinas of functionally disabled eyes with defective vision connected with strabismus.

The final conclusion is not obvious. It seems that normal vision has a statistically confirmed influence on the development of retinal vessels. Defective vision connected with strabismus is disturbing the process of arborisation of the retinal vessels. The retinal vessels of the patient eyes with normal vision differ from the normal pattern as defined by fractal dimensions of control eyes.