Abstract
Purpose::
Ocular ischemic syndrome is characterized by decreased blood pressure of the retina and the choroid due to severe stenosis of ophthalmic artery or occlusion of internal carotid artery. We evaluated the blood flow of the retina, choroid and the optic disc using laser speckle flowgraphy (LSFG).
Methods::
LSFG obtains the relative blood flow velocity, so called square blur rate (SBR) by speckle phenomenon of the moving erythrocytes. Latest model of LSFG or LSFG-wide illustrates the animated blood flow map involving the posterior fundus. We obtained the blood flow map of the posterior fundus in 12 cases with internal carotid artery occlusion and 18 normal volunteers. We measured SBR at the retinal arteries, retinal veins, optic nerve head, the macula and the choroid. We evaluated the disparity of blood flow in bilateral eyes in ICAO and normal volunteers.
Results::
LSFG-wide showed animated blood flow map synchronized with cartiac rhythm. SBR had no significant difference at each measured areas in both eyes of 18 normal volunteers. The disparity of SBR in both eyes was limited within 80-124% at retinal arteries, 77-129% at retinal veins, 85-119% at the optic nerve head, 78-128% at the macula and 79-129% at the choroid. In 12 patients with ICAO, four had decreased vision ranged 0.06 to 0.08 (average0.07) (group VL), four had transient blindness (group TB), and the remaining 4 had no subjective symptoms (group N). In group VL, SBR was lower in the affected eyes at each measured areas. The rate of SBR in the affected eye to the fellow eyes were 28% at retinal arteries, 30% at retinal veins, 65% at optic nerve head, 56% at the macular region, 51% at choroidal region. There was no significant difference of SBR between the affected and fellow eyes in group TB. The rate of SBR in the affected eyes to the fellow eyes were 113% at retinal arteries, 102% at retinal veins, 105% at optic nerve head, 101% at the macular region, 99% at choroidal region. The group N also had no significant difference in both eyes, the rate of SBR were 97% at retinal arteries, 91% at retinal veins, 91% at optic nerve head, 109% at the macular region, 95% at choroidal region.
Conclusions::
LSFG revealed decreased ocular blood flow in the affected eyes with decreased vision in OIS. This noninvasive technique can apply ocular vascular diseases.
Keywords: laser • ischemia • blood supply