1. The sudden appearance of “redness, swelling, heat, and pain” in the eyelid is a typical sign of acute inflammation caused by bacterial infection of the eyelid glands, called blepharitis. This is commonly referred to as “needle’s eye”. 2. Itching and burning sensations in the eyes and redness of the skin on the lid margins are mostly blepharitis, also known as “rotten eyes” or “red eyes”. 3. When waking up in the morning, the upper and lower eyelids are often stuck with large amounts of sticky or purulent secretions, and there is a sensation of foreign bodies or burning in the eyes, as well as slight tearing or pain, mostly due to acute infectious conjunctivitis, commonly known as “red eye” or “violent fire eye. 4, the eyes have significant irritation symptoms, fear of light, tearing, pain, vision loss, gray or yellow-white ulcers on the corneal surface, mostly keratitis. 5. Difficulty in seeing at night or in dark places, dry bulbar conjunctiva, loss of moist luster, mostly night blindness. Night blindness often occurs in malnourished children, often accompanied by systemic malnutrition manifestations, such as wasting, low and hoarse cry, mental depression, etc. 6, self-perceived visual deformation, a dark area in the visual field, there are often flashes of light or sparks in front of the eyes, flash hallucinations, or often feel a black shadow floating back and forth in front of the eyes, then may suffer from chorioretinitis. If you often feel that your vision is distorted, straight lines are seen as curves, sometimes objects are slightly larger, sometimes they appear smaller, and sometimes white objects are seen as yellow, you may have central chorioretinopathy. 7.Self-perceived flies in front of the eyes, black dots or black blocks floating in front of the eyes, vision loss and other symptoms should be considered as the possibility of vitreous liquefaction, cloudiness or degeneration. 8. If there is no change in eye shape, sudden overnight blindness, or even no light perception, it may be central retinal arteriosclerosis or venous thrombosis. If you feel a floating black dot in front of your eyes, loss of vision, or sudden vision loss, or only remaining light perception, you should consider retinal perivenous inflammation. 9. There is pain around the eye or slight pain when the eye moves, the visual field is narrowed or even partially defective, the red-green field is involved, hemianopia or dark spot occurs, often one eye develops and the other eye has a sharp loss of vision or even complete blindness in a short period of time, often with headache and intraorbital pain. Intraorbital pain is aggravated by eye rotation or pressure on the eyeball and may be due to optic neuritis.