Differences among normal eyes, myopia and hyperopia
Normal eye: under the condition of accommodating relaxation, the focus of parallel light passing through the refractive system of the eye falls on the retina. It’s what people call normal vision.
Myopia: when the eye is in a state of relaxation, the focus of the refraction of the parallel light through the refractive system of the eye falls in front of the retina. The patient’s subjective feeling is that the near object is clear while the far object is fuzzy.
Hyperopia: when the eye is in a relaxed state, the parallel light enters the eye and forms the focus after the retina, and the external objects cannot form a clear image in the retina. The patient’s subjective feeling is far from clear, but near is more fuzzy. Many people think that farsightedness is to see clearly in the distance, which is wrong.
Concave lens for myopia and convex lens for hyperopia
There are four main differences between myopia and hyperopia
First, the causes are different. Myopia is usually caused by congenital genetic factors or acquired bad habit of using the eyes. Hyperopia is usually caused by the late development of the eyes or the short axis of the eyes.
Second, the age of onset is different. Myopia is commonly seen in teenagers, while hyperopia is commonly seen in children and infants. The younger the age is, the more likely it will appear.
Third, the prognosis of the disease is different. With the growth of age, the degree of myopia will become larger , while the degree of hyperopia will generally become smaller . If the degree is not large, it may even return to normal.
Fourth, the refractive state is different. Myopia is generally manifested as an increase in the refractive power of the eye, while hyperopia is caused by a decrease in the refractive power of the eye.