BOLD fMRI in patients before and after multifocal intraocular lens implantation

Abstract

Background. In practical ophthalmology during cataract surgery, patients are increasingly being implanted with multifocal intraocular lenses (mfIOLs), which form several foci on the retina. The appearing of new factors creates conditions for human neuroadaptation, the parameters of which can be assessed using a modern research method – functional magnetic resonance imaging (fMRI). Purpose: to determine the change in the nature of the activation of the visual brain cortex in response to stimulation after surgery for the implantation of a multifocal artifi cial lens. Materials and methods. The study included patients with cataract (n = 22), who underwent structural neuroimaging and BOLD fMRI to assess neuronal activity before and after mfIOL implantation. The Gabor element was used as a stimulus for performing BOLD fMRI (unilluminated and ill uminated versions). fMRI data (positive BOLD effect) were processed using the SPM 12 software package in the Matlab R2017a environment. Evaluation of the research results was carried out at the individual and group levels. Results. When evaluating individual results after mfIOL implantation, patients show more local activation of the cerebral cortex, gravitating towards the area of the spur sulcus, while before surgery, the cortical response is more diffuse. In a group analysis in patients after mfIOL implantation, the total volume of the activation cluster of the cerebral cortex signifi cantly increased by 27 times. Maximum activation is noted in the pulvinar on the right and the lingual gyrus on the left. The activation of the cortex in the study with red illumination of Gabor element after surgery is less than in the study with white illumination, and less than in the study after surgery without illumination of Gabor element. Conclusions. A signifi cant but ambiguous change in the neuronal activity of the cerebral cortex on various stimulation options in patients after mfIOL implantation was established. Further work in this area is planned