Abstract: according to the degree of myopia, Ametropia with myopia greater than 600 degrees (more than 400 degrees in children) is called high myopia. Because this kind of myopia is often accompanied by pathological changes in the eyes, blood stations generally do not advocate blood donation.
Once a classmate was discouraged by the nurse who donated blood because of his myopia of 800 degrees. He was very depressed. But there is a scientific basis for high myopia not to allow blood donation. Why?
high myopia why can’t you donate blood?
are divided according to the degree of myopia, Ametropia with myopia greater than 600 degrees (more than 400 degrees in children) is called high myopia. Because this kind of myopia is often accompanied by pathological changes in the eyes, blood stations generally do not advocate blood donation. Generally speaking, there are few complications of mild myopia (less than 300 degrees), while high myopia (greater than 600 degrees) the anterior posterior diameter of the eyeball is significantly longer, but the retina and choroid cannot grow accordingly, resulting in the elongation and diffuse atrophy of the retina and choroid, and the corresponding blood vessels become thinner. In this way, the blood vessels are very sensitive to the change of blood pressure, and the vitreous body can change from colloidal to liquid.
There will be slight fluctuations in blood pressure during blood donation. For those with high myopia whose fundus blood vessels are pulled thin, slight blood pressure fluctuations may cause fundus vasospasm, resulting in a hole in the diseased retina. At this time, the liquefied vitreous body will take the opportunity to enter under the retina, resulting in retinal detachment and seriously affecting vision. Therefore, from the perspective of protecting blood donors, people with high myopia should not donate blood. Experts from
said that myopic blood donors are not uncommon in daily life. Because the degree of high myopia is not clearly specified in China’s blood donation standards, taking into account factors such as astigmatism, in general practice, it is usually based on about 500 degrees to patiently persuade myopic blood donors.
complications that may occur in patients with high myopia
patients with high myopia may have the following complications in addition to the above dangerous situations during blood donation.
people with this disease often have dark shadows floating in front of their eyes with the rotation of their eyes, just like mosquitoes and flies flying, which is due to the liquefaction of the normal colloidal structure of the vitreous.
2. Macular hemorrhage
for people with high myopia, due to the continuous traction of the eyeball wall caused by the enlargement of the eyeball, it will cause metabolic disorders in the normal relationship between the fundus retina and choroid tissue, especially when the small blood vessels in the macular area are broken due to traction and other factors, it will cause macular hemorrhage and greatly damage the central vision. At this time, the patient realized that there was a fixed shadow blocking his line of sight. Although the bleeding can be absorbed after treatment, it will always leave blood marks more or less, affecting vision.
3. Retinal detachment
is a serious complication with complex causes. From the internal cause, the retinal tissue of patients with high myopia becomes fragile due to degeneration and atrophy, which is very easy to make retinal detachment and blindness. The external cause is mainly the sudden impact of external force, which promotes retinal rupture through vitreous conduction, resulting in retinal detachment and blindness.
suggest that patients with high myopia should have an eye health examination every six months.