Bifocals are some of the most popular multifocal lenses that some specific wearers tend to select. They can to the greatest extent help wearers see objects clearly. Also, they can help prevent the emergence of some problems. However, sometimes, they are not perfect as people have thought of. As for sufferers of age-related eye problems, as presbyopia, they usually choose bifocals.

In fact, among the family of multifocal lenses, trifocals are very special and outstanding. As their names indicate, there are three prescriptions in each of these lenses. Wearers can use these lenses as they need, no matter where or what to see. As for sufferers of presbyopia, trifocals are very practical and effective. As it has mentioned that there are three prescriptions in each pair of trifocals, there are different diopters that are responsible for long, intermediate and short distance vision.

The structure of trifocals is also very special. The bottom parts are composed of two areas, each of which is responsible for short and intermediate distance vision. Such design is the result of considering of people’s daily habits, such as reading etc.

In the middle part of the lenses is the area that is repossible for intermediate distance vision. It can not correct the vision, but the pictures of the objects can be expanded by the lens. Such lenses are nice for computer users.

Lastly, the top part is responsible for the vision of long distance. Myopia and farsightedness can also be corrected in this part if some prescriptions are made.

Presbyopia, a Latin word, which is related to aging, means sight loss with aging process. Especially for those who are over40 such problem is a very common problem. Some methods, as surgery, are used to deal with it. In the meantime, trifocals are also good alternatives.

Trifocals are combination of three lenses with three prescriptions. Sometimes, wearers can also choose some progressive glasses which include PALs, varifocal lenses, etc.

You may be interested in these eyeglasses：#SD2267 #SD2305 #YLT0518 #SDSB2033 #VOV5105 #YGJR2817 #SD2241

Most of us have heard of bifocals, but seldom of trifocals. In fact, trifocals are much nicer than bifocals in terms of vision correction.

The history tells us that presbyopia is so hard-dying that it can not be solved by ordinary eyeglasses. Luckily, trifocals are glasses that are mainly for sufferers of presbyopia. There are three lenses in trifocals; each of them is used to cope with the matter of near distance, intermediate distance and long distance respectively.

The aforesaid information can clearly explain the working mechanism of trifocals. Thus, the disadvantage of bifocals in solving this problem can also be detected from it.

In fact, there are two parts in the bottom of trifocals, each of which is responsible for the correction of near and intermediate near vision

From what have been expounded above, we can easily know that the bottom part of the glasses is for short sightedness correction.

Just above the short sightedness-correcting part is the part for intermediate vision. It is responsible for the correction of intermediate distance, which is relatively narrower than other parts.

It is, doubtless, the upper part that is responsible for distant vision-correction. Other eye problems can also be solved in this part.

Different from other eye problems, as nearsightedness and farsightedness, presbyopia is an age-related problem. People over 40 are prone to this eye disease. The cause of presbyopia is that the eye muscles are losing their elasticity. The commonest methods, except LASIK surgery, can not fundamentally solve this problem.

Aimed at the mechanism and symptoms of presbyopia, some designers have devised trifocals which are proved to be one of the most effective methods. However, trifocals are not suitable for all people who have different eye structures. These people can choose varifocals that are designed almost under the same mechanism as trifocals. Anyway, suffers of presbyopia can gain the greatest comfort by wearing trifocals or related glasses.

related article

·Presbyopia causes and treatments

·Brief introduction of presbyopia

·Presbyopic people benefit from new contact lens—-bifocal lens