Farsightedness and myopia are both types of refractive errors, but they are different. The difference between farsightedness and myopia Farsightedness is a state of refraction in which the eye looks at a distant target without adjustment and the parallel light rays are refracted through the refractive system of the eye and the focal point falls behind the retina. Myopia, on the other hand, is a refractive state in which the focal point falls in front of the retina in the above situation. Farsightedness is clear in the distance and blurred in the near, while myopia is clear in the near and blurred in the far. The causes of myopic hyperopia are different: the common cause is a short anterior-posterior axis of the eye (called axial hyperopia), followed by a weak refractive power of the eye (called refractive hyperopia). Farsightedness can also be thought of as ocular hypermetropia, which is generally often hyperopic in children and decreases in degree with age. Farsighted eyes are prone to visual fatigue symptoms due to long-term regulatory tension. Farsightedness requires increased refractive power to see long-distance targets, and more accommodation to see near-distance targets. Farsightedness can be corrected with a convex lens. Whereas myopic eyes need increased refractive power to see distant targets, myopic eyes a concave lens corrective treatment. The dangers of farsightedness and myopia are different. The dangers of farsightedness, in addition to affecting near and far vision, are due to the long-term over-contraction of the internal rectus muscle, one of the regulating muscles, resulting in muscle fatigue symptoms, soreness of the eye, orbital pain, along with dizziness and brain swelling. The child may have difficulty concentrating in class, have poor memory, and hate to read and write, resulting in a decline in academic performance. In farsighted eyes, the strengthening of their regulation will definitely increase the excitability of the internal rectus muscle. If the hyperopia in one eye is serious, in order to make the eye see clearly, the adjustment must be increased, and the excitability of the internal rectus muscle must be increased compared with the normal eye, so some farsighted eyes form internal strabismus, which is one of the more important factors of farsightedness. Myopia leads to many complications that are harmful 1. Retinal detachment: In retinal detachment, 70% are myopic eyes, which is the most common complication of myopia. Due to myopic eye axis elongation and intraocular nutritional disorders, cystic degeneration and lattice-like degeneration often occur in the peripheral part of the retina, and the retina in the degeneration area is very thin and easily perforated, and some of them are already perforated in the fissure, plus vitreous liquefaction and increased mobility, pulling the retina to detachment. 2. Cataract: The nutritional metabolism in myopic eyes is not normal, so that the lens capsule membrane permeability changes, the lens nutritional disorders and metabolic disorders gradually become cloudy, and the vision gradually decreases to produce concurrent cataract. This kind of cataract develops slowly, and core clouding and posterior capsule clouding are the main causes. Macular hemorrhage and macular degeneration: Myopic eyes have poor blood supply and retinal ischemia, and the retina produces a kind of neovascular growth factor, which causes the growth of neovascularization under the retina, and the wall of these neovascularization is extremely thin, so it is easy to rupture and bleed, and macular hemorrhage is formed after bleeding. After the hemorrhage is absorbed, the new blood vessel can rupture and hemorrhage again, and after many times of hemorrhage, local scar will be formed, resulting in macular degeneration, and macular degeneration will permanently damage vision. 4.Vitreous liquefaction degeneration: vitreous body is colorless and transparent jelly-like. When the myopic eye enlarges, the vitreous does not increase again, so the vitreous cannot fill all the space in the eye, appearing liquefaction, increased mobility, clouding, causing black shadows in front of the eyes, inducing retinal detachment. 5, glaucoma: Myopic eyes have abnormal filter curtain structure at the anterior chamber angle, so the atrial water flow resistance in the eye is greater, easily causing an increase in intraocular pressure. According to statistics, 30% of highly myopic eyes have glaucoma, and this glaucoma will cause gradual loss of vision. 6, strabismus, amblyopia: myopia can cause exotropia or exotropia, such as the difference between the myopia of both eyes is greater than 300 degrees, easy to cause the degree of deep eye exotropia and amblyopia.