The most common form of myopia is axial myopia, in which the anterior and posterior axes of the eye are too long and parallel light rays enter the eye and focus in front of the retina. But does all myopia require glasses? At least the following types of myopia do not require glasses. 1. Pseudomyopia. Patients with symptoms of myopia, which can be confirmed by contrast optometry, will disappear or be significantly reduced after dilating the pupil with a ciliary muscle paralyzing agent. These patients can be cured by using a lower concentration of ciliary muscle paralyzing agent in drops. 2. Refractive index myopia. Myopia caused by an increase in the refractive index of the refractive medium. For example, in anterior uveitis, the protein content of the atrial fluid increases, and the refractive index of the atrial fluid increases, causing myopia symptoms. However, there are also factors such as ciliary muscle contraction and pupillary constriction that can aggravate myopia symptoms. These patients can be treated correctly and promptly and the myopia symptoms can disappear. 3. Drug myopia. This is a myopic condition caused by the use of certain types of medications, most commonly the use of ophthalmic medications such as mucopolysaccharide and toxic lentil, which narrow the pupil and stimulate the ciliary muscle spasm, causing tension in the regulation and resulting in myopic symptoms. If the IOP is successfully controlled by surgery, the use of these drugs is stopped or the dosage is reduced, the myopia symptoms will gradually decrease and finally disappear, restoring the original refractive state. 4. Diabetic myopia. When the blood glucose content increases to a certain level, the sugar content in the eye should also increase. The lens may be in a relatively “hypertonic state” due to the increased glucose content, and water may penetrate through the lens capsule membrane and into the lens cortex, resulting in edema of the lens, resulting in increased refractive power and myopia symptoms. The degree of diabetic myopia is often unstable, but when diabetes is effectively treated and blood sugar is controlled at a normal level for a period of time, myopia symptoms will gradually decrease to disappear. 5, aviation myopia and night myopia. When the pilot is flying at high altitude, the field of vision outside the cabin is a void, because there is no target attraction, but will stimulate the adjustment, causing myopia symptoms. Once back on the ground, myopia disappears naturally. Night myopia and aviation myopia is very similar, people are surrounded by a blanket of night, will also stimulate the regulation, causing myopia symptoms, once back to a brighter place, myopia symptoms will disappear. 6, hyperbaric myopia. Some people suffer from some other diseases, need for hyperbaric oxygen therapy. After a total of one hour of continuous hyperbaric oxygen therapy, most of them can have myopia symptoms. The reason may be due to the dilatation of the blood vessels in the eye, resulting in impaired circulation, swelling of the lens, increased refractive power and myopia symptoms. This kind of myopia is also temporary, and as the hyperbaric oxygen treatment ends, the myopia will gradually decrease until the original refractive state is restored. All of these myopia symptoms are temporary and functional, and basically do not require glasses to correct the vision. Therefore, it is sometimes necessary to ask the patient about his or her condition during optometry to avoid misprescription of glasses.