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 Zheng Xin
Ophthalmology
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Does nearsightedness surgery require hospitalization?

Myopia surgery does not require hospitalization; it is completed on an outpatient basis. Before the surgery, routine blood tests, screenings for infectious diseases, and specialized eye examinations are conducted. If the pre-operative examinations are thorough and there are no contraindications for surgery, the procedure can be performed on an outpatient basis. After the surgery, patients can go home and must return to the surgical hospital the next day for a follow-up examination. Post-operative medication should be used as prescribed by the surgeon, and regular follow-up appointments should be scheduled.

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Written by Hu Shu Fang
Ophthalmology
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What department should you visit for nearsightedness?

People with nearsightedness should visit the ophthalmology department, as it is a major type of refractive error in outpatient services. Nearsightedness means clarity when looking at close objects, but blurriness when viewing objects at a distance. Currently, nearsightedness in adolescents is a significant health issue in China. Patients with nearsightedness should see an ophthalmologist at a qualified hospital for eye examinations to rule out any eye diseases, and then wear prescription glasses with the correct diopters to prevent the progression of nearsightedness. Additionally, those with nearsightedness must regularly visit the doctor to check their eyes.

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Written by Li Zhen Dong
Ophthalmology
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Is 1000-degree acquired myopia hereditary?

High myopia of 1000 degrees can also be inherited. The inheritance of myopia is mainly significant in cases of high myopia. If both parents have high myopia, the heritability is almost above 90%. If one parent has high myopia, the heritability is 45%. If neither parent is myopic, the heritability is nearly 5%. Myopia is primarily formed due to improper use of eyes rather than hereditary factors, which are relatively rare and generally only account for about 10% of myopia cases. Therefore, correct use of eyes is very important.

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Written by Peng Xi Feng
Ophthalmology
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The main cause of myopia formation

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
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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.