The examination of the optic fundus constitutes an essential part of the mass health screening course. However, the significance and the use of its findings are yet to be clarified fully. So, we have recently conducted two research studies.
One is concerned with quantitation of information made available about the changes in the blood vessels in the retina of the eye. Following a basic investigation in which the diameter of retinal vessles was measured, we examined changes in the diameter of retinal arteries after administration of vasodilators in search of the relationship between vasodilation and arteriosclerosis.
The other is concerned with a comparative study of abnormal retinal findings and the occurrence of cerebral apoplexy. We closely examined the appearance ratios of retinal abnormalities and compared them with the data obtained in our previous study of the incidence of cerebral apoplexy over the period of five years.
The subjects are rural inhabitants of the Yuri district, Akita Prefecture, which is noted for its high incidence of cerebral apoplexy in this country. Particularly in the Yuri district, not only the aged but people under 60 years of age are frequently attacked with cerebral apoplexy.
Our current survey findings showed that the average diameter of retinal vessels-both arterial and venous-was slightly small compared with those reported by other researchers. The dilation of retinal arteries after intravenous injection of 20mg of nicotinic acid was large in the moderate arteriosclerosis group and small in the advanced arteriosclerosis group.
The appearance of retinal abnormalities increased as the age of the subjects advanced.
Hypertensive retinopathy was predominant among those aged between 30 and 49, while among those aged 50 or above arteriosclerotic changes were observed as frequently as any abnormality. Irrespective of age, the subjects who showed retinal abnormalities developed symptoms of cerebral apoplexy at a significantly higher rate than those who did not show any abnormality in the eyeground. Particularly, the narrowing of the retinal arterioles was observed at a notably high rate.
Thus, it has been proved that the eyeground examination is effective in predicting cerebral apoplexy and useful in mass health screening.
