Summers Robert J, Heitmar Rebekka
School of Life and Health Sciences, Aston University, Birmingham, UK.
Centre for Vision Across the Lifespan (CVLS), School of Applied Sciences, University of Huddersfield, Huddersfield, UK.
J Vasc Res. 2025;62(1):1-9. doi: 10.1159/000541443. Epub 2024 Nov 19.
The dilatory response of healthy retinal arterioles to flicker-light (FL) provocation appears to be biphasic. The vessel diameter rapidly increases (acute phase) over 5-10 s, then barely increases thereafter (maintenance phase) until FL cessation. This reaction is usually characterised at a single point by two parameters: maximum dilation (MD) relative to baseline diameter (MD, %) and time to MD (RT, s). This paper describes the biphasic reaction of retinal arteries during FL provocation using a bi-linear function.
Retinal arterioles from 45 adults were examined during flicker provocation. Each individual time course of arterial diameter change during FL provocation was characterised by a bi-linear equation and compared with MD and RT.
Slopes of the acute phase were 0.506%/s, and the maintenance phase was nearly flat (0.012%/s). The mean time at which the reaction changed from acute to maintenance phase was 7.4 s which is significantly different from RT (16.0 s). Mean dilation at this point (2.987%) was significantly different from MD (3.734%), but it was still 80% of MD in less than half of RT.
Bi-linear fitting parameters better characterises the arterial dilatory response than MD and RT. Further stratification of clinical groups using bi-linear fitting may provide insight of the underlying physiology of vessel dilation for different pathologies.
The dilatory response of healthy retinal arterioles to flicker-light (FL) provocation appears to be biphasic. The vessel diameter rapidly increases (acute phase) over 5-10 s, then barely increases thereafter (maintenance phase) until FL cessation. This reaction is usually characterised at a single point by two parameters: maximum dilation (MD) relative to baseline diameter (MD, %) and time to MD (RT, s). This paper describes the biphasic reaction of retinal arteries during FL provocation using a bi-linear function.
Retinal arterioles from 45 adults were examined during flicker provocation. Each individual time course of arterial diameter change during FL provocation was characterised by a bi-linear equation and compared with MD and RT.
Slopes of the acute phase were 0.506%/s, and the maintenance phase was nearly flat (0.012%/s). The mean time at which the reaction changed from acute to maintenance phase was 7.4 s which is significantly different from RT (16.0 s). Mean dilation at this point (2.987%) was significantly different from MD (3.734%), but it was still 80% of MD in less than half of RT.
Bi-linear fitting parameters better characterises the arterial dilatory response than MD and RT. Further stratification of clinical groups using bi-linear fitting may provide insight of the underlying physiology of vessel dilation for different pathologies.
健康视网膜小动脉对闪烁光（FL）刺激的扩张反应似乎是双相的。血管直径在5 - 10秒内迅速增加（急性期），此后几乎不再增加（维持期），直至FL停止。这种反应通常由两个参数在单个时间点进行表征：相对于基线直径的最大扩张（MD，%）和达到MD的时间（RT，秒）。本文使用双线性函数描述了FL刺激期间视网膜动脉的双相反应。
在闪烁刺激期间检查了45名成年人的视网膜小动脉。FL刺激期间动脉直径变化的每个个体时间进程由一个双线性方程表征，并与MD和RT进行比较。
急性期的斜率为0.506%/秒，维持期几乎是平的（0.012%/秒）。反应从急性期转变为维持期的平均时间为7.4秒，这与RT（16.0秒）有显著差异。此时的平均扩张（2.987%）与MD（3.734%）有显著差异，但在不到RT一半的时间内，它仍为MD的80%。
双线性拟合参数比MD和RT能更好地表征动脉扩张反应。使用双线性拟合对临床组进行进一步分层可能会为不同病理状态下血管扩张的潜在生理学提供见解。
健康视网膜小动脉对闪烁光（FL）刺激的扩张反应似乎是双相的。血管直径在5 - 10秒内迅速增加（急性期），此后几乎不再增加（维持期），直至FL停止。这种反应通常由两个参数在单个时间点进行表征：相对于基线直径的最大扩张（MD，%）和达到MD的时间（RT，秒）。本文使用双线性函数描述了FL刺激期间视网膜动脉的双相反应。
在闪烁刺激期间检查了45名成年人的视网膜小动脉。FL刺激期间动脉直径变化的每个个体时间进程由一个双线性方程表征，并与MD和RT进行比较。
急性期的斜率为0.506%/秒，维持期几乎是平的（0.012%/秒）。反应从急性期转变为维持期的平均时间为7.4秒，这与RT（16.0秒）有显著差异。此时的平均扩张（2.987%）与MD（3.734%）有显著差异，但在不到RT一半的时间内，它仍为MD的80%。
双线性拟合参数比MD和RT能更好地表征动脉扩张反应。使用双线性拟合对临床组进行进一步分层可能会为不同病理状态下血管扩张的潜在生理学提供见解。
