Gunawardene Araliya N, Reyes Nicholas, Valdes-Arias David, Ortug Alpen, Martinez Jaime, Galor Anat, Moulton Eric A
Ophthalmology, Miami Veterans Affairs Medical Center, 1201 NW 16 Street, Miami, FL, 33125, USA.
Bascom Palmer Eye Institute, University of Miami, 900 NW 17 Street, Miami, FL, 33136, USA.
Am J Ophthalmol Case Rep. 2024 Nov 6;36:102213. doi: 10.1016/j.ajoc.2024.102213. eCollection 2024 Dec.
Friedreich ataxia (FDRA) is a debilitating neurodegenerative disease that can have ophthalmological manifestations including visual dysfunction, nystagmus, and optic atrophy. However, severe photophobia has not been reported nor evaluated with functional magnetic resonance imaging (fMRI).
A 64-year-old white female with a 37-year history of FDRA presented to the eye clinic with worsening photophobia of 3 years. To measure her visual cortex activation and subjective responses during episodes of photophobia, she underwent event-related fMRI with light stimuli. In comparison, the same protocol was conducted in an individual with photophobia but without FDRA. After the fMRI, both patients were treated with 35 units of BoNT-A applied to the forehead.
Analysis of visual cortex activity in response to light stimulus in the FDRA patient showed no correlation between blood oxygen level dependent (BOLD) activation and light stimuli in the first (r = -0.100, p = 0.235), and a weak negative correlation in the second half of the fMRI scan (r = -0.236 p = 0.004). In notable contrast, significant positive correlations were noted between visual cortex activity and the light stimulus (1st half: r = 0.742, p < 0.001, vs. 2nd half: r = 0.614, p < 0.001) in the comparator Six weeks later, no improvement in photophobia was noted in either patient.
Our study highlights photophobia as one potential ocular manifestation of FDRA and suggests that one underlying contributor may be a decoupled cortical neurovascular response to light. Our study provides novel information that may guide physiologic understanding and future treatments in this disease.
弗里德赖希共济失调（FDRA）是一种使人衰弱的神经退行性疾病，可出现包括视觉功能障碍、眼球震颤和视神经萎缩在内的眼科表现。然而，严重畏光现象尚未见报道，也未通过功能磁共振成像（fMRI）进行评估。
一名64岁白人女性，有37年FDRA病史，因畏光加重3年就诊于眼科门诊。为了测量她在畏光发作期间的视觉皮层激活情况和主观反应，她接受了光刺激事件相关fMRI检查。作为对照，对一名有畏光但无FDRA的个体进行了相同的检查。fMRI检查后，两名患者均在前额注射了35单位的肉毒杆菌毒素A（BoNT-A）。
FDRA患者对光刺激的视觉皮层活动分析显示，在fMRI扫描的前半部分，血氧水平依赖（BOLD）激活与光刺激之间无相关性（r = -0.100，p = 0.235），而在后半部分存在弱负相关（r = -0.236，p = 0.004）。显著的是，在对照者中，视觉皮层活动与光刺激之间存在显著正相关（前半部分：r = 0.742，p < 0.001；后半部分：r = 0.614，p < 0.001）。六周后，两名患者的畏光症状均未改善。
我们的研究强调畏光是FDRA的一种潜在眼部表现，并表明一个潜在因素可能是皮层对光的神经血管反应解耦。我们的研究提供了新的信息，可能有助于对该疾病的生理理解和未来治疗。
