The difference between hyperopia and myopia

Abstract: the abnormal nutritional metabolism in myopia changes the capsular permeability of the lens, and the lens is gradually turbid due to nutritional and metabolic disorders. The visual acuity is gradually reduced, resulting in complicated cataract. This kind of cataract develops slowly, mainly core opacity and posterior capsule opacity.

hyperopia and myopia are both kinds of ametropia, but they are different.

definition of hyperopia myopia difference

hyperopia is a refractive state in which the focus falls behind the retina after the parallel light is bent through the refractive system of the eye when the eye looks at a distant target in an unregulated state. Myopia is a refractive state in which the focus falls in front of the retina in the above case. Hyperopia is characterized by a clear view of the distance and a blurred view of the near, while myopia is characterized by a clear view of the near and a blurred view of the far. The causes of hyperopia in

and

myopia are different: the common cause is the short anterior and posterior axis of the eye (called axial hyperopia), followed by the weak refractive power of the eye (called refractive hyperopia). Hyperopia can also be considered as ocular hypoplasia. It is usually hyperopia in children, and the degree decreases with age. Hyperopia is prone to visual fatigue because it is in a state of tension for a long time.

and

hyperopia eyes need to increase their refractive power to see long-range targets, and need more adjustment to see short-range targets. Hyperopia can be corrected by convex lens. Myopia needs to increase refractive power to see distant targets, and a concave lens correction is used for myopia.

hyperopia and myopia have different hazards from

hyperopia. The hazards of

hyperopia not only affect the near and far vision, but also cause muscle fatigue, eye soreness, orbital pain and dizziness due to the long-term excessive contraction of internal rectus muscle, one of the regulating muscles. Children will have inattention in class, poor memory, hate reading and writing, so their academic performance will decline.

and

hyperopia will increase the excitability of internal rectus muscle after the strengthening of its regulation. If the hyperopia degree of one eye is serious, in order to make the eye see the scenery clearly, it must increase regulation. The excitability of internal rectus muscle must be increased than that of normal eyes. Therefore, some hyperopia eyes form esotropia, which is one of the more important factors in the harm of hyperopia.

myopia leads to many complications, which do great harm.

1. Retinal detachment: 70% of retinal detachment is myopia, which is the most common complication of myopia. Due to axial elongation and intraocular dystrophy in myopia, cystic degeneration and lattice degeneration often occur around the retina. The retina in the degenerative area is very thin and prone to perforation. Some have been perforated and formed in the hole. In addition, vitreous liquefaction and increased mobility lead to detachment of the traction retina.

2. Cataract: the nutritional metabolism in myopia is abnormal, which changes the capsular permeability of the lens, gradually produces turbidity due to lens nutritional disorder and metabolic disorder, and gradually reduces vision, resulting in concurrent cataract. This kind of cataract develops slowly, mainly core opacity and posterior capsule opacity.

3. Macular hemorrhage and macular degeneration: myopia has poor blood supply and retinal ischemia. The retina produces a kind of neovascular growth factor. These factors make the subretinal neovascularization grow. These neovascularization tube walls are very thin and easy to rupture and bleed. Macular hemorrhage is formed after bleeding. After the bleeding is absorbed, the new blood vessels can rupture and bleed again. After multiple bleeding, local scars will form and cause macular degeneration, which will permanently damage vision.

4. Vitreous liquefaction and degeneration: the vitreous is colorless and transparent jelly. When the eyeball of myopia increases, the vitreous body will not increase again, so the vitreous body can not fill all the space in the eye, resulting in liquefaction, increased mobility and turbidity, causing dark shadow in front of the eyes and inducing retinal detachment.

5. Glaucoma: the filter curtain structure at the anterior chamber angle of myopia is abnormal, so the outflow resistance of aqueous humor in the eye is large, which is easy to cause the increase of intraocular pressure. According to statistics, 30% of high myopia have glaucoma, which will cause the gradual loss of vision.

6. Strabismus and amblyopia: myopia can cause exotropia or exotropia. If the difference between the degrees of myopia in both eyes is greater than 300 degrees, it is easy to cause deep exotropia and amblyopia.