Abstract: high myopia, also known as pathological myopia, has a diopter of more than 600 degrees and a maximum of 4000 degrees. Generally, the disease occurs earlier, the axial diameter of the eyeball is continuously lengthened, and a series of pathological changes can occur in many tissues of the eyeball. , myopia, from different angles, can be classified in a variety of ways:, (1) According to clinical pathology, simple myopia: that is, general myopia, medium and low myopia with a diopter of less than 600 degrees, and the progressive development of myopia is slow. The eyeball tissue is normal without pathological changes. High myopia, also known as pathological myopia, has a diopter of more than 600 degrees, up to 4000 degrees. Generally, it occurs early, the axis diameter of the eyeball is constantly lengthened, and the eye is hard to see A series of pathological changes can occur in many tissues of the ball., (2) according to the degree of myopia, low myopia: myopia with diopter less than or equal to – 300 degrees, moderate myopia: myopia with diopter between – 300 and – 600 degrees, high myopia: myopia with diopter higher than – 600 degrees.
myopia can be classified in many ways from different angles:
(1) according to clinicopathological
and
Simple myopia: that is, general myopia. Medium and low myopia with diopter below 600 degrees, and the progressive development of myopia is slow. The eyeball tissue was normal without pathological changes.
and
are high myopia, also known as pathological myopia. Their diopter exceeds 600 degrees, up to 4000 degrees. Generally, the disease occurs earlier, the axial diameter of the eyeball is continuously lengthened, and a series of pathological changes can occur in many tissues of the eyeball.
(2) according to the degree of myopia,
low myopia: those whose diopter is less than or equal to – 300 degrees.
medium myopia: those whose diopter is between – 300 and – 600 degrees.
high myopia: those whose diopter is higher than – 600 degrees.
(3) according to the diopter component,
A. axial myopia is caused by the excessive development of the anterior and posterior axis of the eye.
B. curvature myopia is caused by excessive bending of the cornea or lens surface.
C. refractive myopia is caused by high refractive index of refractive stroma.
D. according to the effect of eye regulation. Such myopia as
and
generally belongs to the category of simple myopia.
and
pseudomyopia: also known as accommodative myopia. The axial diameter of the eyeball is normal, but the refractive power of the refractive stroma exceeds the norm. Generally, the lens is over regulated. Therefore, distant light enters the eye and is imaged in front of the retina. After mydriasis, the diopter of myopia completely disappeared, manifested as emmetropia or hyperopia.
and
true myopia: also known as axial myopia, the refractive power of the refractive stroma is normal, the anterior and posterior diameter of the ocular axis is prolonged, and the distant light is imaged in front of the retina after entering the eye.
mixed myopia: the state of true and false myopia at the same time. After mydriasis, the diopter of myopia decreased more, but it was still myopia. Juvenile myopic students are in this state of myopia in the process of heavy learning tasks and physical development.
myopia is an eye disease characterized by clear near vision and blurred far vision, Its symptoms and clinical manifestations mainly include:
(1) visual function: the most prominent symptoms are the reduction of far vision, the higher the degree of myopia, the worse the far vision, the lower the photosensitivity of myopia, the expansion of physiological blind spots of pathological myopia, the abnormality of peripheral visual field in the early stage, and the reduction of contrast sensitivity.
(2) Visual fatigue: myopic people who often use their eyes may have photophobia, dry eyes, foreign body sensation, heavy eyelids, eye pain, headache and other phenomena, especially in astigmatism, anisometropia, excessive eye use or poor general condition. Low myopia leads to fatigue due to uncoordinated adjustment and collection.
(3) Eye position deviation: due to the uncoordinated adjustment and collection during myopia, visual fatigue is easy to occur in order to maintain a short-term balance due to the inherent uncoordinated. If the balance is out of balance, the eye position will change, manifested as exophoria or exotropia.
(4) Eyeball changes: the anterior posterior diameter of eyeball becomes longer, the eyeball protrudes forward, and the high myopia is obvious. The change of eye axis length is only after the equator.