Transient visual symptoms such as blurry vision, and field defects including homonymous hemianopsia have also been reported in patients with MMD. Ocular manifestations in MMD are uncommon, but several case reports have described varying ocular manifestations including amaurosis fugax, central retinal artery occlusion, morning glory disc anomaly, and ocular ischemic syndrome. In adults, intracerebral, intraventricular, or subarachnoid hemorrhages occur more frequently than ischemic symptoms. Headaches, involuntary motor disturbances, and seizures can also occur. The main symptoms in children are transient ischemic attacks (TIA), which can occur repeatedly and on alternating sides because the occlusions are bilateral. The two main types of symptoms in MMD are cerebral ischemia and hemorrhage. The estimated prevalence of MMD in Japan almost doubled between 1994 to 2003, probably due to advances in neuroradiological diagnostic techniques, which helped identify new cases. It is likely that multiple factors are linked that underlie the pathophysiology of MMD. These cytokines are associated with causing vessel narrowing and occlusion by promoting smooth muscle proliferation into the tunica intima, but it is still unknown if they are the cause of MMD. Additionally, many cytokines such as VEGF, bFGF, and TGF-β1 have been found in MMD patients. Some genetic studies of familial MMD propose that responsible genetic loci are located on chromosomes 3, 6, and 17. The etiology of MMD is largely unknown, but due to the higher incidence of this disease in Japanese populations and the presence of familial cases, it is thought that MMD could be a multifactor disease. While other case reports in North America were found to be isolated and ~ 4% familial Familial cases of MMD were reported to be 12.1%. The male to female ratio was 1:1.8, and the peak of prevalence was in the second decade in males age in the third decade for females. In 2003, the incidence of MMD was reported to be 0.54 per 100,000 in Japanese populations, which is ten times the incidence in North America and Europe. The incidence of MMD is highest among Japanese and Koreans, and much lower in Caucasians. The term “moyamoya” is a Japanese word which means a hazy puff of smoke, used to describe the abnormal appearance of the vascular network seen in angiograms of patients with MMD. The progressive ischemia results in the formation of a collateral vascular network in the base of the brain. Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disorder affecting the terminal portions of the bilateral internal carotid arteries or proximal portions of the anterior and middle cerebral arteries.
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