To measure your lenses, you can go to your local optician or hospital's optometry center and use a special instrument called an anemometer to measure your lenses.
There is also a very simple "proximity" test for lens prescription. Stretch out your finger in front of your eyes 18 centimeters test, if the eyes look very natural, and then look at the distance, if it is also very natural, it shows that the glasses optometry is accurate. On the contrary, it is not accurate.
The 18 centimeters is for people under 25 years old, and the distance varies by age. 20 to 22 centimeters for those in their 30s, 22 to 25 centimeters for those in their 35s, 25 to 28 centimeters for those in their 40s, and 28 to 30 centimeters for those over 45.
Extended information:
Visual Abnormalities
1. Myopia
Myopia is a condition in which you can see near objects clearly and far objects blurrily, and is professionally defined as "a condition in which a distant object is refracted by the eye and focused in front of the retina, rather than forming a clear image on the retina". Myopia is the most common eye disease among Chinese children, and the rate of high myopia in mainland China is much higher than that of children in other countries and regions. Many eye diseases derived from high myopia are threatening the vision and eye health of many children.
2. Hyperopia
Focusing on the retina after refracting the light from the eye, a blurred image is formed on the retina. Therefore, people with hyperopia can't see clearly both near and far. Myopia is rare in infants and young children, and more than 90% of preschoolers are farsighted, the vast majority of which is physiologic and a manifestation of normal eye development. 20% to 25% of hyperopia is pathologic, and it is the main cause of children's low vision and poor eye development.
3, amblyopia
An amblyopia is a disease that seriously affects visual function, referring to those who have no obvious organic lesions of the eyeballs, but the distance and near visual acuity is less than 0.8, and can't be sedan chair. According to statistics, amblyopia patients have more than 15 million people, becoming a social problem that we need to pay urgent attention to.
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