Views:123 Author:Site Editor Publish Time: 2020-08-27 Origin:Site
Reading optical glasses, also known as presbyopic glasses, are a kind of optical products. They are utilized by people with presbyopic eyes and belong to a convex lens. Reading optical glasses are mainly to meet the needs of people with presbyopia.
Reading optical glasses are to supplement the eyesight of the middle-aged and old people. They have many national standard optical indexes as well as some special rules of utilizaton. The usage of reading glasses plays an indispensable role in improving people's quality of life.
Presbyopia is a normal physiological phenomenon, not an eye disease, nor unique to the elderly. After 40 years old, with the gradual hardening of the lens and the gradual paralysis of the ciliary muscle, the human eye can not effectively adjust the shape of the eye (axial change). Only by adjusting the distance between the eye and the object people are looking at, when they look at the near object, they must move far to see clearly. At this time, the eye state is called presbyopia.
In order to use vision at the original distance, it is necessary to wear magnet reading glasses to supplement the vision, so as to make the vision near and clear again. The degree of presbyopic is related to age. For example, at the age of 45, presbyopia is + 1.50D (i.e., 150 degrees), and at 50, whether glasses are worn or not, presbyopia will increase to + 2.00D (i.e., 200 degrees). If there is already presbyopia and reading glasses are not worn, then the exhaustion of ciliary muscle can not be adjusted. It will definitely aggravate the reading difficulty, produce many symptoms such as dizziness and eye swelling, and affect life and work, which is very unwise. Therefore, reading optical glasses should be matched immediately without delay.
A good smart reading glasses is to meet the optical requirements, have a price tag, and wear comfortable. It mainly embodies the following aspects.
Due to the aggregate effect of sight at close range of presbyopia and the habit of reading and writing, the monocular axis should move downward and inward by 2.5mm when looking far (looking horizontally) on the lens. The pupil is generally above and below the midline of the lens when looking horizontally, so to make the presbyopia have enough field of vision. The lens should meet the requirement that the upper and lower height is greater than 30mm, not that the smaller the lens are, the better they will be. The upper and lower narrow lens types within 25 mm are generally portable for temporary vision supplement.
Because the users of reading optical glasses are all over middle age, with plump face, and although the horizontal size of reading glasses is generally 10 mm larger than that of optical frames, the distance between the near pupil and the far pupil is less than 5mm, so the OCD value should be 58-61 mm for women and 61-64 mm for men. In order to meet these two requirements at the same time, it is necessary to use a large diameter lens and have a large amount of light center displacement in the production.
Reading optical glasses is a kind of proximity glasses. The rule of reading optical glasses is from 40 years old (+ 1.00D, i.e. 100 degrees) in reading distance, and it needs to be supplemented with + 0.50D (i.e. 50 degrees) every five years. In addition, the frequency of removing and wearing glasses in the use process is dozens of times that of myopia glasses, so the parts of reading glasses must be solid or high elastic materials. The anti-corrosion and anti scratch performance of electroplating must be outstanding, and the hardening process of lens should be better. On the whole, it is necessary to ensure that no serious deformation, rust and rubbing will occur within 2 years. In fact, on these points, for a good adjustable reading glasses, the requirements are higher than those of the same grade glasses frame.
For the sake of eye health, the safest way is to wear appropriate progressive reading glasses for correction.