Healthy eyes are black and white, bright and clear. The eyeball is flexible and does not protrude, sink or deviate. The eyeballs are moderately soft and hard, and the tear ducts and tear glands are open. The eyelids should be bright yellow and open and close freely. The inner and outer corners of the eyes are light red, and the whites of the eyes are lustrous and transparent with a tough white color. The black eyes are greenish black or brown. The two pupils are equally sized and round, and they adjust in size with the intensity of the light, spreading and shrinking freely. In life, what we call the white of the eye is known as the sclera in medical terms. A normal sclera is white, and a normal eye is clear and transparent, and evenly colored, without spots or bumps. However, if there is a color change in the sclera, such as cloudy, red, blue, etc., it is important to be alert. So, what does the abnormal color of the sclera really say? People often say that the eyes are the windows to the soul, but in fact, the eyes are also a window to the health of the whole body. You can see the health status of your body through the change of eye color, which is also a part of Chinese medicine diagnosis. The eye can be divided into five parts: the eyelid, the corner of the eye, the white of the eye, the black eye, and the pupil. Traditional Chinese medicine has always said that the five chakras, the eyelids belong to the spleen, the corners of the eyes belong to the heart, the whites of the eyes belong to the lungs, the black eyes belong to the liver, and the pupils belong to the kidneys, are like five wheels, one over the other. There are two corners of the eye, the inner and outer corners, which contain tiny blood vessels that reflect the function of the heart. For example, when the heart fire is strong, the inner and outer corners of the eyes will be red, and then it is time to clear the heart fire. The white color of the eyes is blood deficiency, and the yellow color indicates that the disease will be healed. A red needle-like spot in the inner corner of the eye is called a “stroke spot” and may be a precursor to a stroke due to high blood pressure. There are many causes of eye redness, but most of them are due to bacterial and viral infections. We know that “pink eye” is a bacterial infection, and there is also conjunctivitis that occurs due to bacterial infection from wearing contact lenses without paying attention to cleaning, which is also characterized by redness of the whites of the eyes. In addition, the white of the eyes will be red before the occurrence of cerebral hemorrhage in patients with hypertension, cardiac insufficiency in patients with severe insomnia, and before the onset of crohn’s disease. Then again, people who have had poor sleep for a long time will have red blood in the whites of their eyes. Finally, if the sclera has a red dot distribution, it is often the result of end capillary dilation, which is mostly found in diabetic patients. It should be said that redness of the sclera is the most common and most suggestive of disease. If the whites of the eyes are red unilaterally, one should be aware of the possibility of an STD infection. In order to keep the whites of our eyes from becoming abnormal, we should be careful to get enough sleep and not use our eyes for long periods of time. In case of dryness, redness, burning, or foreign body sensation, we should go to the hospital promptly.