How many degrees is 45 on the eyesight chart

I believe everyone should have had the experience of testing their eyesight. When testing you, the doctor will ask you to sit on a bench, usually about 3 to 5 meters away from the eye chart. The doctor will then point to each number on the eye chart with his fingers, and then say what he sees. The results of the eye test chart are usually not the degree of your own vision, but rather the degree of your vision. So how many degrees does 4.5 degrees of vision mean for the eyes?

How many degrees is 4.5 vision

Visual acuity of 4.5 is the number represented by the line that can be seen in the international standard visual acuity chart. 4.5 means that one can see the 6th line. This is just an examination standard.

The degree of myopia refers to the diopter, which is the reciprocal of the focal length F of the refractive system.

However, clinical practice has confirmed that visual acuity and refraction are not completely proportional, so there is no conversion formula between the two. For example, someone with 800 degrees of myopia can see 4.2 when looking at the eye chart, while another person with 300 degrees of myopia can only see 4.0 when looking at the eye chart.

Myopia needs to be checked by computer optometry. Parents can take their children to professional optometry institutions for examination to control the deepening of myopia in time and avoid the following eye complications:

Eye fatigue

Due to unclear vision, the eyes increase their accommodation, and the eye muscles are in a state of excessive tension for a long time, which can easily cause eye fatigue. Symptoms such as eye swelling, eye pain, orbital pain, dizziness, and nausea may occur.

Macular hemorrhage and degeneration

Degenerative myopia is caused by lesions in the fundus, which can cause macular hemorrhage, atrophy and degeneration of the retina and choroid, and seriously affect vision.

Causes strabismus

After myopia occurs, the eye uses less accommodation and more convergence when looking at close objects, which causes an imbalance between accommodation and convergence. The medial rectus muscle is in a state of excessive tension for a long time. Over time, this causes insufficient function of the medial rectus muscle and a corresponding weakening of the convergence function of both eyes, which can easily lead to exotropia or exotropia.

Retinal detachment

Due to the elongation of the eye axis and the liquefaction and degeneration of the vitreous body, the fibrous cords in the vitreous body can adhere to the retina and pull on the retina. When the eyeball is impacted or traumatized, it can cause retinal rupture and retinal detachment. Retinal detachment is the most serious complication of high myopia, and vision is extremely reduced. If not treated in time, it can lead to blindness.