Ophthalmic manifestations of Huntington’s disease

Abstract

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a mutation in the huntingtin gene. The whole nervous system, including visual analyzer, is involved in the pathogenesis of the disease. Various ocular sings can be found in both preclinical and clinical stages of HD. Specific retinal damage, namely, abnormal proteins formation, photoreceptor degeneration and retinal remodeling, has been studied in animal models. Functional changes in occipital lobe activity and its atrophy as well as degeneration of visual pathways can already be present in the early stages of the disease. Oculomotor symptoms of HD include disturbed visual fixation, slower tracking eye movements and saccades, and suppressed vestibulo-ocular reflex. Visual perceptual disorders, such as visuospatial difficulties, problems of stimulus identification and motion perception, along with decreased contrast sensitivity, have also been described. The possibility of using certain ophthalmic parameters as biomarkers of HD is being discussed.

Retinal and choroidal morphological changes in Huntington's disease

“…Было выполнено «ослепление» специалистов, проводивших обследование пациентов, учтены основные факторы, способные повлиять на состояние зрительного нерва, сетчатки и хориоидеи, проводился контроль качества изображений [39][40][41]. Впервые был проведен анализ комплекса ГКС и установлена его дегенерация, что дополняет сведения о дегенерации различных структур зрительного анализатора при БГ [42]. Увеличение объема выборки и дифференцированный анализ толщины сетчатки в 9 секторах позволили впервые выявить уменьшение толщины сетчатки в наружном височном секторе, сочетающееся со снижением толщины СНВС в височном, нижнем и назальном квадрантах.…”

Vergence and Strabismus in Neurodegenerative Disorders

“…Ophthalmologic symptoms have also been reported; specifically, saccade latency is increased along with anti-saccade error rate and impaired ability to suppress saccades ( 90 – 93 ). In contrast, vestibulo-ocular reflex and smooth pursuit movements are relatively preserved until late into the disease ( 93 , 94 ). Of note, a slight increase in saccade latency and a decreased number of memory-guided saccades were found in presymptomatic Huntington gene carriers compared to non-gene carriers, suggesting that oculomotor control in Huntington could serve as an early biomarker ( 95 ).…”