Danyang Factory 1.56 photochromic round top bifocal HMC AR prescription lenses optical for glasses

1. Round Top Bifocal Lens

As people age, they may find that their eyes are not adjusting to distances as they used to. When people inch closer to forty, the lens of the eyes begin to lose flexibility. It becomes difficult to focus on close objects. This condition is called presbyopia. It can be managed to a large extent with the use of bifocals.

Bifocal (also can be called Multifocal) eyeglass lenses contain two or more lens powers to help you see objects at all distances after you lose the ability to naturally change the focus of your eyes due to age.

Bifocal means that there are two different diopters on the same lens. The two diopter are distributed in different areas of the lens. The area for viewing far is called the far field, which is located in the upper part of the lens. The near zone is located in the lower half of the lens. The object in the far distance can be seen through the far-field of a pair of lenses, and the close-range objects can be seen through the near-field of the same pair of lenses. You don't need to carry two pairs of glasses with you, you don't need to switch between distant and near-eye glasses frequently.

2. Photochromic Lens

What are the photochromic lens?

Photochromic lenses are made of many lens materials including plastic, glass or polycarbonate. They are typically used as sunglasses that conveniently switch from a clear lens indoors, to a sunglasses depth tint when outdoors, and vice versa.

They typically take around 30 seconds to fully darken and approx 2 - 5 minutes to return to a clear state.

The advantages of the photochromic lens?

1. Reduced costs – buying a single pair of dual purpose photochromic glasses that can provide vision for both indoors when clear and providing sunglasses protection outside is more cost effective than buying two separate pairs. 2. UV protection - Photochromic lenses provide full protection against the harmful UV rays of the sun and direct exposure to sunlight can cause serious eye problems and in some cases blindness.

3. Convenience - You only need to own 1 pair of glasses for both indoors and outdoors in the sun as opposed to needing to switch between 2 pairs of regular glasses to sunglasses. You only need to remember to take one dual purpose pair of glasses with you as no doubt at some point we have all forgotten to take our sunglasses out with us only to be caught out by the glare of the sun or even left them behind never to be seen again.

4. Eye Health – Reducing your exposure to the suns harmful UV rays can lower the risk of cataracts or other eye/age related problems.