Caring Futures Institute, Flinders University, Bedford Park, SA 5042, Australia; College of Nursing and Health Sciences, Optometry and Vision Science, Sturt North, Flinders University, Bedford Park, SA 5042, Australia.
Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Victoria Park Road, Kelvin Grove 4059, Brisbane, QLD, Australia.
J Optom. 2023 Jan-Mar;16(1):53-63. doi: 10.1016/j.optom.2022.04.002. Epub 2022 May 17.
The intrinsically photosensitive retinal ganglion cells (ipRGCs) regulate pupil size and circadian rhythms. Stimulation of the ipRGCs using short-wavelength blue light causes a sustained pupil constriction known as the post-illumination pupil response (PIPR). Here we examined the effects of ipRGC stimulation on axial length changes to imposed optical defocus in young adults.
Nearly emmetropic young participants were given either myopic (+3 D, n = 16) or hyperopic (-3 D, n = 17) defocus in their right eye for 2 h. Before and after defocus, a series of axial length measurements for up to 180 s were performed in the right eye using the IOL Master following exposure to 5 s red (625 nm, 3.74 × 10 photons/cm/s) and blue (470 nm, 3.29 × 10 photons/cm/s) stimuli. The pupil measurements were collected from the left eye to track the ipRGC activity. The 6 s and 30 s PIPR, early and late area under the curve (AUC), and time to return to baseline were calculated.
The PIPR with blue light was significantly stronger after 2 h of hyperopic defocus as indicated by a lower 6 and 30 s PIPR and a larger early and late AUC (all p<0.05). Short-wavelength ipRGC stimulation also significantly exaggerated the ocular response to hyperopic defocus, causing a significantly greater increase in axial length than that resulting from the hyperopic defocus alone (p = 0.017). Neither wavelength had any effect on axial length with myopic defocus.
These findings suggest an interaction between myopiagenic hyperopic defocus and ipRGC signaling.
光感受器神经节细胞（ipRGCs）可调节瞳孔大小和昼夜节律。短波长蓝光刺激 ipRGCs 会引起持续的瞳孔收缩，即光刺激后的瞳孔反应（PIPR）。本研究旨在探讨 ipRGC 刺激对年轻人受光学离焦影响的眼轴变化的影响。
将基本正视的年轻参与者右眼给予近视（+3 D，n = 16）或远视（-3 D，n = 17）离焦 2 小时。在离焦前后，右眼使用 IOL Master 进行了长达 180 秒的一系列眼轴测量，在暴露于 5 秒红光（625nm，3.74×10 光子/cm/s）和蓝光（470nm，3.29×10 光子/cm/s）刺激后进行。从左眼收集瞳孔测量值以跟踪 ipRGC 活动。计算 6 秒和 30 秒 PIPR、早期和晚期曲线下面积（AUC）以及恢复到基线的时间。
与远视离焦 2 小时后相比，蓝光刺激后的 PIPR 明显更强，表现为 6 秒和 30 秒 PIPR 更低，早期和晚期 AUC 更大（均 p<0.05）。短波长 ipRGC 刺激也显著夸大了远视离焦的眼部反应，导致眼轴增长明显大于单纯远视离焦（p=0.017）。两种波长对近视离焦均无影响。
这些发现表明，远视性近视离焦与 ipRGC 信号之间存在相互作用。
