What is hyperopia?

When the distant parallel light enters the refractive system of the human eye, it forms a focus behind the retina, which is called hyperopia. Use a convex lens to increase the concentration of light, so that the focus falls on the retina, can get a clear image.

Many people confuse presbyopia with hyperopia, perhaps because they use convex lenses. In fact, the two concepts are completely different.

The optometry principle of hyperopia is the maximum positive diopter in the clearest state, that is, the diopter should be given as clear and as high as possible+ 3.25 See 1.0,+3.00 see 1.2,+2.75 see 1.2,+2.50 see 1.0, we take+3.00 to match the lens.

If hyperopia is undercorrected (for example,+2.75 is selected), the focus will be behind the retina, and the lens will also bulge, so the human eye will be easily tired, and more adjustment is required to look closer, so it will be easy to be tired.

For people with hyperopia, most of them are caused by poor eye development in childhood. For people with poor living conditions in childhood, their nutrition has not kept up with them, which hinders the development of their eyes. All newborn babies have hyperopia, about+3.00. With the growth of age, the eye axis slowly grows, and then the focus can fall on the retina to form a clear vision. This process is called emmetropia. He became hyperopia when he was not well developed. Low hyperopia often does not appear blurred when young, because the lens plays a regulatory role. You can pull the focus to the retina. When you get older, the elasticity of the lens decreases, which shows that your vision is blurred. The hypermetropic person will have a higher degree of nearsightedness due to the addition of an orthoscopic lens.

Precautions for glasses:

It is recommended to select a full frame type, because the convex lens is thick in the middle and too thin at the edge. If a half frame is selected, the lens at the Nie side is too thin and needs to be grooved and wiredrawn, which is easy to collapse and damage.

The size of the high hyperopia frame is also very particular. The size of the mirror ring cannot be too small, because the middle is thick and the edge is thin. If the ring is too small, the thin part on the edge will be worn off, leaving the thickest part. If it is too thick, the beauty and stability of the assembly will be reduced. The lens ring should not be too large. Too large lens ring size will affect the amount of center shift. The normal 65 diameter may not be able to achieve the actual pupil distance.

For the same hyperopia degree, the smaller the diameter of hyperopia lens blank, the thinner the lens will be.

Therefore, the frame size selected for high hyperopia should not be too large. It is better not to center shift or center shift of 1-2 mm. The higher the degree, the higher the requirement.

We need to do two things well:
1) The appropriate frame shall be stable and comfortable to wear, and the displacement shall be as small as possible.
2) Then calculate the minimum lens blank diameter to make the farsighting lens diameter as small as possible.