Shortsighted
Introduction
Introduction Myopia is a concept of vision. It refers to the range of gaze, the things that are clear and close, and the things that are far away. Including refractive myopia and axial myopia, the so-called myopia is generally referred to as refractive myopia, so myopia and myopia are two different concepts. Mild or moderate myopia, except for obscurity, there are no other symptoms. When working at close range, you can see the small target without adjusting or using less adjustment, but it is convenient, but at high myopia, work. When the target distance is very close, the two eyes are too inward to gather, which will cause the use of excessive rectus muscles and visual fatigue symptoms.
Cause
Cause
There are many reasons for refractive errors. Genetic factors are very important reasons. Of course, unreasonable use of the eye is also a reason that cannot be ignored. Children are in a period of growth and development, and they do not pay attention to eye hygiene. For example, reading and writing postures are incorrect. Or the light is not good, causing the distance between the eye and the book to be too close, or reading for too long, or walking, reading a book by car, etc. can cause excessive eye fatigue and promote refractive error.
Examine
an examination
Related inspection
Vision eye examination
Subjective inspection method:
1. Determine the refractive properties method based on preliminary analysis of visual acuity.
2. Insert optometry.
3. Cross-column and astigmatism optometry.
4. Cloud law.
5. Astigmatism optometry.
6. Pinhole sheet and slit sheet inspection method.
7. Laser speckle pattern method.
Objective inspection method:
1. Direct ophthalmoscopy.
2. Retinoscopy.
3. Strip photo retinoscopy.
4. Corneal meter.
5. Automatic refractometer and so on.
Vision diagnosis
That is, those with near vision 1.0 and far vision <1.0 are myopic (the visual acuity chart used is different, and there are different recording methods, such as the standard logarithmic visual acuity chart, the record of low far vision is <5.0). Age males <0 years old and females <45 years old, the near vision should be 1.5, and the difficulty test distance is 25cm.
Refractive diagnosis
That is, the retinal retinoscopy under ciliary muscle paralysis presents myopic refraction (-0.25D). The theoretical diagnostic criteria should be: far vision force <1.0, eye axis length>24mm, and adjust the retinal sacral shadow under paralysis as myopic refraction (minimum diopter is at least -0.125D). However, it is still difficult to be so accurate and clear about the conditions and levels already in place at the beginning of the 21st century.
Fundus diagnosis
Regardless of the type of myopia, the fundus should be examined to initially estimate the weight of myopia and true and false myopia. Generally, there is a myopic arc spot, and the leopard-like fundus changes, which can be diagnosed as true myopia, and its diopter is about -300 degrees or higher. Some are accompanied by macular degeneration and bleeding, etc., if the fundus is normal, it may be mild myopia or pseudo myopia. An experienced ophthalmologist can estimate the approximate refractive state based on the diopter on the ophthalmoscope.
Diagnosis
Differential diagnosis
1, high myopia:
The myopia of refractive myopia can reach more than 600 degrees. Symptoms of high myopia are basically axial myopia.
The anterior chamber of high myopia is deep, the pupil is large, and the eyeball is slightly protruding due to the length of the front and rear axles. White or gray-white crescent-shaped plaques on the temporal side of the optic disc, known as myopic meniscus, are due to the posterior scleral elongation, retinal pigment epithelium and choroidal dislocation from the lateral edge of the optic disc, exposing the sclera or part of the choroid and sclera. . The posterior sclera is continuously posteriorly dilated. In the macula, there are knee-like streaks and subretinal neovascularization, and plaque-like atrophy and degeneration in the nearby retina and choroid, leading to posterior scleral staphyloma. The macula often has pigmentation and even hemorrhage, forming a Forster-Fuchs spot, which seriously impairs vision. High-myopic macular degeneration has become one of the main causes of blindness. Such patients are often accompanied by vitreous liquefaction, turbidity, and a small number of retinal detachments and complicated cataracts.
2. Mild or moderate myopia:
Myopia is between 300 and 600 degrees. In addition to observing distant objects, there are no other symptoms. When working at close range, you can see the small targets without adjusting or using less adjustments. However, when working in high myopia, the target distance is very close, and the eyes are too inward to gather, which will cause excessive use of the medial rectus and symptoms of visual fatigue. Mild and moderate myopia, no special changes in the eye, but occasionally myopia half moon spot and leopard-like fundus changes. Myopia can lead to incomplete collection and exotropia.
