The difference between astigmatism and myopia, the symptoms are different

Many people have vision problems of one kind or another, the most common ones are astigmatism and myopia. You should know that there is a difference between astigmatism and myopia. With astigmatism, you cannot see clearly no matter how near or far the objects are, while with myopia, you can only see clearly nearby objects.

1. Symptoms of astigmatism

⑴ Simple myopic astigmatism among the symptoms of astigmatism: parallel light rays on a principal meridian form an image on the retina, and parallel light rays on another meridian perpendicular to it focus in front of the retina to form an image.

⑵ Simple hyperopic astigmatism: Parallel light rays on a principal meridian form an image on the retina, and parallel light rays on another meridian perpendicular to it form an image focused behind the retina.

⑶ Symptoms of astigmatism: compound myopic astigmatism: On two mutually perpendicular main meridians, parallel light rays are imaged in front of the retina, but their refractive powers are not equal.

⑷ Compound hyperopic astigmatism, a symptom of astigmatism: On two mutually perpendicular principal meridians, parallel light rays are imaged behind the retina, but their refractive powers are not equal.

⑸Mixed astigmatism among the symptoms of astigmatism: On two mutually perpendicular principal meridians, one parallel light ray forms an image in front of the retina, while the other parallel light ray on the meridian focuses and forms an image behind the retina.

2. Symptoms and signs of myopia

When the eyeball is in a static state of accommodation, equal light rays coming from 5 meters away will focus exactly on the retina after refraction by the eye, forming a clear image. An eye with this refractive state is called an emmetropia. The focus falls in front of the retina and cannot accurately form a clear image on the retina, which is called axial myopia. However, it is highly adaptable to scattered light from nearby targets, and clear vision can be achieved as long as the target moves to a certain distance in front of the eyes. Therefore, myopia can see close objects clearly but far objects are blurred, which can be corrected by concave spherical lenses.

1. Distant vision decreased, near vision normal;

2. Visual fatigue;

3. Exotropia or co-rotational exotropia may occur, and the strabismic eye is usually the one with the higher degree of myopia;

4. People with high myopia often experience vitreous liquefaction and turbidity, complicated by cataracts, and feel that black shadows are floating in front of their eyes or vision is reduced;

5. For low and moderate myopia, the fundus is generally unchanged or has a leopard-like fundus, solitary macules for myopia, and annular choroidal atrophy around the temporal or peripheral optic disc for high myopia, macular degeneration, hemorrhage, Fuchs spots, posterior scleral staphyloma, and retinal holes and retinal detachment are prone to occur;

6. People with high myopia have slightly protruding eye axes due to their long eye axes, and their anterior chambers are deeper and their pupils are larger, and they are slightly slow in responding to light. 7. Using concave spherical lenses can improve vision.