The difference between nearsightedness and farsightedness.

Written by Li Zhen Dong
Ophthalmology
Updated on September 26, 2024
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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 Li Zhen Dong
Ophthalmology
42sec home-news-image

Can eye fatigue lead to nearsightedness?

Myopia is characterized by clear vision up close but blurry vision at a distance, primarily caused by changes in the eye's axial length. Several factors contribute to the development of myopia: first, hereditary factors; second, inappropriate use of eyes, such as prolonged usage leading to eye fatigue, which can worsen the degree of myopia. Typically, the development of myopia occurs under the age of 20. After 20, there shouldn't be further development; if there is, it is referred to as pathological myopia. Therefore, it is important for patients with myopia or eye fatigue to use their eyes correctly, reduce close-up activities to avoid eye strain, and have regular check-ups to monitor their vision.

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Written by Zheng Xin
Ophthalmology
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Can glaucoma patients undergo myopia surgery?

Glaucoma is a group of eye diseases characterized by atrophy of the optic nerve and defects in the visual field. Common symptoms include reduced vision, eye pain, and loss of visual field. In terms of treatment, it primarily involves the use of medications to control eye pressure or anti-glaucoma surgery to manage eye pressure, which helps delay the atrophy of the optic nerve and the loss of vision. However, since glaucoma has already caused damage to the optic nerve, it is generally not recommended to undergo myopia surgery, as it cannot improve vision.

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Written by Lian Wen Xi
Pediatrics
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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
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At what degree of myopia do you need to wear glasses?

Myopia is a refractive state in which, when the eye's accommodation is relaxed, parallel light rays from the outside, after passing through the eye's refractive system, focus in front of the retina, this condition is called myopia. The occurrence of myopia is influenced by a combination of various factors including genetics and environment. Common clinical symptoms of myopia include decreased vision, which also affects normal daily life. It is recommended to wear glasses regardless of the degree of myopia if it impacts daily activities.

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Written by Deng Jiang Tao
Ophthalmology
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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.