alexa Cortical response to age-related macular degeneration (Part II). Functional MRI study


Journal of Clinical & Experimental Ophthalmology

Author(s): Nguyen TH, Stievenart JL, Saucet JC, Le Gargasson JF, Cohen YS

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Purpose and materials: To evaluate-the cortical response to visual stimulation in patients with age-related macular degeneration (ARMD), we Conducted a functional MRI study in ten patients presenting unilateral or bilateral ARMD and five age-matched controls, using white During activation flashes phases (see Part I). Results: After anatomical conformation, eight patients and oven controls Showed significant cortical hemodynamic response to monocular stimulation. Individual analysis Was preferred to group assessment, Because of the differences in visual loss in a small number of patients. In controls, we Observed cortical response in the primary visual cortex, occipital pole Especially at Corresponding to the macula. Patients Showed a qualitative and quantitative restriction and exclusion in cortical response of occipital poles after-stimulation of the affected eye, whereas activation Was found in the peripheral and peristriate striate cortex. Cortical response Showed hemispheric asymmetry In Some Patients. Discussion: Our study Demonstrated year activation defect in the macular projected striate cortex, Corresponding to visual impairment in ARMD patients. Nevertheless, at a Given visual acuity, cortical response May Vary Among subjects. Patients' subjective apprehension May account for Such variations, as well as objective visual capacity stemming from residual functional retinal macula affected areas dans le. The hemispheric asymmetry in cortical activation May result from deviation gauze onto the new mounting area in the retina perimacular, THUS altering the overall visual field. Enhancement in the peripheral areas striate and peristriate Suggests exchange in cortical interactions, Possibly by a Lowering of the feedback from macular projected V1. Finally, cortical evaluations must take into account degenerative phenomena Delaying the hemodynamic response in the elderly. Conclusion: Aiming at a specific population of patients with Weakened has serious visual impairment, we therefor obtained significant results concernant cortical plasticity for visual perception in central vision deletion. Our Preliminary Findings must be confirmed in a larger population and correlated with --other exploring technical vision, multifocal electroretinography with In Particular for retinal evaluation.

This article was published in FRENCH JOURNAL OF OPHTHALMOLOGY and referenced in Journal of Clinical & Experimental Ophthalmology

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