How many degrees of myopia disqualify someone from donating blood?

Jun 23, 2025 Source: Cainiu Health

Dr. Liu Feng

Introduction

Myopia exceeding 600 degrees is classified as high myopia. At this stage, the anteroposterior diameter of the eyeball is significantly elongated, causing the retina and choroid to become thinner due to prolonged stretching, and the blood vessels can also be affected. During blood donation, the body's blood volume temporarily decreases, causing blood pressure fluctuations that may alter the intraocular vascular pressure, increasing the risk of retinal detachment, macular hemorrhage, and other fundus lesions, thus threatening eye health.

Generally, individuals with myopia exceeding 600 degrees are usually advised not to donate blood. The detailed explanation is as follows:

Myopia exceeding 600 degrees is considered high myopia. In such cases, the anteroposterior diameter of the eyeball is significantly elongated, causing the retina and choroid to become thinner due to prolonged stretching, and the blood vessels are also affected. During blood donation, the body's blood volume temporarily decreases, causing blood pressure fluctuations that may alter the pressure on ocular blood vessels, increasing the risk of retinal detachment, macular hemorrhage, and other retinal diseases, thereby threatening eye health.

For common myopia, where the refractive error is 600 degrees or less, the structural changes in the eye are relatively minor, and the impact on the retina and choroid is slight. Provided other health conditions meet the blood donation criteria, moderate blood donation will not cause significant adverse effects on the eyes or increase the likelihood of developing eye diseases.

Prior to donating blood, individuals should truthfully inform medical staff about their myopia status and ocular medical history, cooperate with all required examinations, and follow professional recommendations to ensure safe blood donation.

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What Should You Eat After Blood Donation?

Generally speaking, there is no specific "best" food to eat after donating blood. However, certain foods can help replenish nutrients and promote recovery, while medications should be used as needed and according to symptoms. Foods typically include lean meat, spinach, red dates, eggs, and pork liver; medications commonly include ferrous fumarate tablets, vitamin C tablets, compound ejiao syrup, iron dextran oral solution, and folic acid tablets. Lean meat is rich in high-quality protein and iron.

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How long after taking cold medicine can I donate blood?

After stopping medication for a full week following a cold, organs such as the liver and kidneys will have mostly metabolized the drugs. Once cold symptoms have subsided and hematopoietic function has recovered, donating blood at this time will neither affect the recipient's health nor cause personal discomfort. However, if less than a week has passed since discontinuing medication, residual drugs may alter blood composition, and the body might not have fully recovered; donating blood under such circumstances could increase risks for the recipient and delay one's own recovery.

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Post-Donation Precautions and Dietary Restrictions

In general, after donating blood, it is important to rest appropriately, replenish nutrition, protect the puncture site, avoid donating blood again in a short period, and monitor your physical condition. It is not recommended to consume spicy food, fried peanuts, white liquor, ice cream, salted fish, etc. Maintaining healthy lifestyle habits after blood donation, such as getting sufficient sleep and engaging in moderate exercise, can help the body recover more quickly.

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Is blood donation beneficial for people with high blood pressure?

Under normal circumstances, if a person with high blood pressure has their blood pressure well-controlled in daily life, donating blood appropriately may provide certain benefits. However, if their blood pressure is not well-managed, donating blood at such times would not be beneficial. If any discomfort symptoms arise, it is recommended to seek timely medical consultation and treatment at a正规 hospital. Before donating blood, it is essential to consult with a qualified physician to confirm whether your health condition is suitable for blood donation.