Highly myopic woman groping for glasses

Myopia means that when the pressure is adjusted and relaxed, the parallel light source is focused in front of the macula after passing through the eye's refractive system, and a clear image cannot be displayed on the macula. Myopia with a diopter of -6D (D refers to diopter) or above is considered severe myopia.

1. Genetic factors

It has been recognized that myopia has a certain genetic tendency, especially for severe myopia. People with genetic factors tend to get sick at an earlier age and their myopia degree is often over 600 degrees. But there are also people with high myopia and no family history. High myopia is an autosomal recessive trait.

2. Growth and development factors

In the neonatal period, the eyes are small and therefore farsighted, but as they grow older, the eye axis gradually lengthens and does not develop normally until after the age of 6. If the growth is too rapid, myopia will occur. This type of myopia is called simple myopia, which usually begins in the preschool period and is generally less than 600 degrees. At around 20 years old, the growth stops. If the myopia progresses rapidly in childhood and even faster at the age of 15 to 20, and then slows down, this type of myopia is often higher than 600 degrees, and can reach 2000-2500 or 3000 degrees. This type of myopia is called deep myopia, idiopathic myopia or pathological myopia. This type of myopia may cause degenerative macular choroidal degeneration in old age, so vision may gradually deteriorate and cannot be corrected by wearing glasses.

3. Environmental factors

People who are engaged in clerical work or other close work are more likely to be myopic. There is also a high incidence of myopia among adolescent students, and the incidence rate increases significantly starting from the fifth and sixth grades of primary and secondary school. This phenomenon shows that the occurrence and development of myopia is closely related to close work. Especially for the eyes of adolescents, which are in the stage of growth and development, their adjustment ability is very strong, and the flexion and extension of the eye wall is relatively large. The adjustment and combination function during close work such as reading makes the medial rectus muscle release a certain amount of pressure on the eyes, and the intraocular pressure may also increase.

Clinical symptoms of severe myopia

1. The vision of the distant eye is reduced, while the vision of the near eye is normal. The combination becomes weak, there will be exotropia or exotropia, and eyestrain will often occur.

2. High myopia is mostly axial myopia, with the front-to-back and left-to-right axis of vision extending, and its extension is basically limited to the posterior pole. Therefore, the main manifestations are prominent eyes, deep anterior chamber, large pupils and slow reflection surface. . In very severe myopia, the lens can no longer support the retina, thus causing slight retinal tremors.

3. Dark adaptation effect is reduced.

4. Severe myopia, due to excessive extension of the eye axis, can cause degenerative changes in the eyes: blood pressure leopard-like fundus; choroid shrinkage around the optic disc; irregular, independent or combined white atrophic spots may form in the macula, sometimes with visible bleeding. In addition, there are some small circular bleeding around the macula, called Foster-Fuchs spots; scleral redness and swelling after weight-bearing; and cystic degeneration of the serrated edge at full term.