The main cause of myopia formation

Written by Peng Xi Feng

Ophthalmology

Updated on September 08, 2024

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Myopia is primarily caused by the focusing system of the eyeball focusing parallel light rays in front of the retina when our eyes are in a relaxed adjustment state. The far point of a myopic eye is at a certain point in front of the eye. The occurrence of myopia is influenced by a combination of factors including genetics and environment, and the incidence is still being explored. Based on the refractive components, myopia can be classified into refractive myopia and axial myopia. According to the degree of myopia, it can be classified into mild myopia (below 300 degrees), moderate myopia (300 to 600 degrees), and high myopia (above 600 degrees). The clinical manifestations of myopia include blurry distance vision but good near vision, often with fluctuating distance vision where squinting is needed to see clearly at a distance.

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Written by Lian Wen Xi

Pediatrics

51sec

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Is a child's vision of 4.7 considered nearsighted?

Children's vision at 4.7 does require a comprehensive analysis to determine if they are nearsighted. Generally, a child with a vision of 4.7 is likely to be nearsighted, but this single parameter should not be used to diagnose myopia. It's necessary to differentiate whether the child has true myopia or false myopia. Additionally, the issue could be amblyopia, astigmatism, or farsightedness. Moreover, the child's age also plays a significant role in assessing vision. For instance, a vision of 4.7 might indicate nearsightedness in a child aged seven or eight, but for a child around three years old, a vision of 4.7 is considered normal. Parents are advised to take their child to the hospital for a dilated refraction test to ascertain the specific condition.

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Written by Zheng Xin

Ophthalmology

49sec

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The difference between amblyopia and myopia.

Amblyopia refers to a condition where, through examination, the eyeball has no organic lesions, but the vision is poor. Even after correction, the vision remains significantly lower than normal, generally less than or equal to 0.8, without any organic lesions in the eyeball. In such cases, amblyopia can be considered. Myopia, on the other hand, refers to poor vision that can reach normal or better levels after correction. The difference between the two is that amblyopia cannot be fully corrected through adjustment, whereas myopia can be completely corrected. In terms of treatment, myopia can be corrected by wearing glasses or undergoing surgery, while amblyopia can only be managed by wearing glasses or undergoing specific amblyopia treatments.

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Written by Li Zhen Dong

Ophthalmology

51sec

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The difference between nearsightedness and farsightedness.

Myopia is characterized by clear vision up close and blurred vision at a distance; hyperopia is characterized by clear vision at a distance and blurred vision up close. The main difference between myopia and hyperopia is the issue with the eye’s axial length. In an unaccommodated state, when parallel light rays enter the eye and focus in front of the retina, it is called myopia; when they focus behind the retina, it is called hyperopia. Myopic glasses are concave lenses, while hyperopic glasses are convex lenses. When myopia or hyperopia occurs, it is important to rest, reduce close-up activities, avoid eye fatigue, use eyes properly, eat a light diet, adjust your attitude, have regular check-ups, and pay attention to vision health.

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Written by Deng Jiang Tao

Ophthalmology

1min

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Does myopia correction rebound?

Will there be a rebound after myopia correction surgery? Generally, it relates to two aspects. The first is associated with your pre-surgery degree of myopia; the second relates to your habits in using your eyes after the surgery. Generally speaking, the higher the degree of myopia before the surgery, the more likely a rebound will occur. Roughly speaking, if your degree of myopia was above 700 degrees before the surgery, there's about a 20% to 30% chance of rebounding. However, a rebound does not mean it will return to the previous degree of over 700; typically, it might rebound by around 100 to 200 degrees. The second aspect is significantly related to your post-surgery visual habits. If, after the surgery, you frequently use computers, read documents, or use your phone, there’s a higher chance of experiencing some degree of rebound. Conversely, if your screen time is less, the proportion of myopia rebound tends to be smaller.

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Written by Zheng Xin

Ophthalmology

51sec

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What lenses should be used for nearsightedness?

Myopia, or nearsightedness, refers to a refractive condition where, in a relaxed state of accommodation, parallel light rays are focused in front of the retina after passing through the eye's refractive system. Myopia is categorized by degree into mild myopia, which is less than or equal to 300 degrees, moderate myopia ranging from 325 to 600 degrees, and high myopia, which is over 600 degrees. Generally, the degree of myopia is within 600 degrees, and most patients do not exhibit any pathological changes in the fundus. They require the use of suitable concave lenses for correction. If the degree of myopia exceeds 600 degrees, a fundus examination is necessary. If there are no special changes in the fundus, correction can also be made using appropriate concave lenses.