The eyes as a window into disease prevention

The search for neuroprotective therapeutic interventions for Huntington disease (HD) is accelerating. Most of the efforts to date have focused on manifest HD, in which the goal of therapeutic trials is to slow the progression of the underlying disease process, and thus decrease the decline in functional and clinical measures.¹ However, the neurodegenerative process begins long before manifest HD can be diagnosed.² Thus it is important to start treatment in this presymptomatic population to postpone the onset of illness (manifest HD). However, the ability to detect a clinical benefit in presymptomatic individuals is challenging due to long and variable time horizons between the presymptomatic stages and disease onset and the clinical heterogeneity surrounding disease onset. Reports in this issue of Neurology by Blekher et al.³ and Golding et al.⁴ describe quantitative assessments of eye movements in presymptomatic and symptomatic individuals with HD that may facilitate the development of meaningful preventive trials.

Both articles describe the systematic evaluation of quantitative eye movements in individuals carrying the HD mutation who are either presymptomatic or have manifest illness. The methods used are simple and robust, requiring only an eye movement tracker (video, infrared, or EOG), and a computer for presenting the targets …