[Physiological mechanism for the regulation of ocular circulation].
Ocular circulation is regulated to maintain the homeostasis of retinal function in response to physiological stimulus. It is important to understand the mechanism of the regulation of ocular circulation under physiological conditions because the impairment of ocular circulation should cause severe retinal disorders. We previously investigated the physiological mechanism of ocular circulation in response to hypoxia, hypercapnia, and acute increased systemic blood pressure. In addition, it was reported that transpupillary thermotherapy might change ocular blood flow in patients with age-related macular degeneration. However, it still remains unclear whether the increased ocular tissue temperature may be associated with alteration of the ocular blood flow. Therefore, we examined the effect of ocular warming on retinal blood flow (RBF) and subfoveal choroidal blood flow (CBF) in humans. Ocular warming was induced in 10 healthy volunteers using an ocular warming lamp for 10 minutes. The RBF in the retinal artery and vein and the CBF in the foveal region were examined with a retinal laser Doppler velocimetry system and a laser Doppler flowmeter, respectively. Ocular warming increased RBF in the retinal artery and vein but decreased CBF in the foveal region. The CBF in the foveal region may contribute to maintaining a constant retinal temperature in response to ocular warming.
Nagaoka
Taiji
T
Department of Ophthalmology, Asahikawa Medical College, Japan. nagaoka@asahikawa-med.ac.jp
D001775:Blood Circulation / Q000502:physiology*; D002829:Choroid / Q000098:blood supply*; D005584:Fovea Centralis / Q000098:blood supply*; D006706:Homeostasis; D006358:Hot Temperature; D006801:Humans; D017078:Laser-Doppler Flowmetry; D009799:Ocular Physiological Phenomena; D012161:Retinal Artery / Q000502:physiology*; D012164:Retinal Diseases / Q000209:etiology; D012169:Retinal Vein / Q000502:physiology*; D013696:Temperature