Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, India.
J Glaucoma. 2024 Sep 1;33(9):624-631. doi: 10.1097/IJG.0000000000002427. Epub 2024 May 16.
Functional near-infrared spectroscopy (fNIRS) was used to assess visual cortical activity in patients with primary open angle (POAG) and primary angle closure (PACG) glaucomas. There was decreased activity in the visual cortex of glaucoma patients correlating with the severity of glaucoma.
To evaluate visual cortex activity using fNIRS in POAG and PACG compared with healthy controls.
A total of 30 POAGs, 31 PACGs, and 30 healthy aged-matched controls from a single centre were recruited in this cross-sectional observational pilot study with purposive sampling. The POAG and PACG groups were age-matched but were not matched for disease severity at recruitment. All participants underwent fNIRS testing using a multichannel continuous-wave near-infrared system NIRSport 8×7 device (NIRx Medizintechnik GmbH). The visual cortex activity was evaluated in terms of the maximum amplitude of change in oxyhemoglobin (OxyHb) concentration over 10 seconds, and a comparison was done among 3 groups. Both POAG and PACG groups were combined (termed as glaucoma group) to assess the relationship of visual cortical activity with disease severity (by visual field defect (mean deviation) and retinal nerve fibre layer thickness).
All participants showed the characteristic response of increased OxyHb and decreased deoxyhemoglobin during stimulus presentation. The maximum amplitude of change in OxyHb concentration over 10 seconds was significantly lower in both POAG and PACG groups compared with control in the right and left middle occipital gyri ( P < 0.05). There was no significant difference between PACG and POAG. Importantly, there was a negative correlation between the visual cortex activity with the visual field defects (mean deviation; P < 0.05) and a positive correlation with retinal nerve fibre layer thickness in the glaucoma group ( P < 0.05).
In patients with glaucoma, a reduction in visual cortical activity was observed, which may be indicative of neuronal degeneration occurring in the occipital cortex. Disease severity in glaucoma appears to be closely correlated with visual cortex activity. fNIRS can serve as a useful neuroimaging modality for assessing the hemodynamic and neurodegenerative changes in glaucoma.
功能近红外光谱（fNIRS）用于评估原发性开角型（POAG）和原发性闭角型（PACG）青光眼患者的视皮质活动。青光眼患者的视皮质活性降低，与青光眼的严重程度相关。
使用 fNIRS 评估 POAG 和 PACG 患者与健康对照组的视皮质活动。
本横断面观察性研究采用目的性抽样，共招募了来自单一中心的 30 名 POAG 患者、31 名 PACG 患者和 30 名年龄匹配的健康对照组。POAG 和 PACG 组年龄匹配，但招募时疾病严重程度不匹配。所有参与者均接受了多通道连续波近红外光谱系统 NIRSport 8×7 设备（NIRx Medizintechnik GmbH）的 fNIRS 测试。评估了 10 秒内氧合血红蛋白（OxyHb）浓度变化的最大幅度，比较了 3 组之间的差异。将 POAG 和 PACG 两组合并（称为青光眼组），以评估视皮质活动与疾病严重程度（通过视野缺损（平均偏差）和视网膜神经纤维层厚度）的关系。
所有参与者在刺激呈现期间均表现出 OxyHb 增加和脱氧血红蛋白减少的特征性反应。与对照组相比，POAG 和 PACG 组右侧和左侧中枕叶的 OxyHb 浓度 10 秒内的最大变化幅度均显著降低（P<0.05）。PACG 和 POAG 之间无显著差异。重要的是，在青光眼组中，视皮质活动与视野缺损（平均偏差；P<0.05）呈负相关，与视网膜神经纤维层厚度呈正相关（P<0.05）。
在青光眼患者中，观察到视皮质活动减少，这可能表明枕叶神经元发生退行性变。青光眼的疾病严重程度似乎与视皮质活动密切相关。fNIRS 可作为评估青光眼患者的血流动力学和神经退行性变的有用神经影像学方法。
