Transition Lenses

Transition lenses are a type of photochromic lenses that automatically darken when they are exposed to the sun's harmful ultraviolet rays, and come back to their original clear state once a person is away from sunlight. How do these lenses work and are there any problems involved with these eyeglasses? That is what we will be finding out in this article.

How Do Transition Lenses Work?

These lenses work because they have photochromic properties. The photochromic properties are brought about because of their ability to change tints in UVB and UV rays. These tints are made possible due to a particular patented dye that helps to activate the lens. This dye is embedded in the form of micro-crystalline silver halides or molecules in a glass substrate. These silver halides are usually taken in the form of silver chloride and work for pieces that are made from a glass material. Similarly, for glasses that are made from a plastic material, organic photochromic molecules are used so that the reversible effect can be achieved. These molecules are usually taken in the form of oxazines or naphthopyrans.

These lenses (or rather the properties in the lenses) react to the UV rays and begin to turn darker as a reaction to the rays. These will begin to darken in less than a minute when they come in contact with the UV rays and will continue to darken very slightly over a period until they finally adjust to allow only a stipulated amount of light to enter the eye. They do not darken to the point of turning into sunglasses. The minute a person gets away from the UV rays, the lens start to fade and come back to their normal color.

Transition lenses are said to work for all forms of glasses, including bifocals, progressives, shatter-resistant, trifocals, standard lenses, and hi-index materials as well.

Pros

Protection for Eyes
The main advantage of these lenses is that it provides for eye care by providing protection from the harmful UV and UVB rays of the sun. These rays have shown to cause varied eye diseases like cataracts, cancers and the like.

Convenient and Economical
When a person opts for transition lenses, he does not need to spend the extra money to invest in a pair of prescription sunglasses, because the function of the sunglasses is done by these lenses itself. So there is no need to spend extra cash as well.

Multipurpose
As said before, these glasses can be worn by all types of numbers-bifocals, numbered, progressive etc. thus they are of a multipurpose usage. Similarly, they can be used by all age groups, even children who have a number. In fact, this might be a very convenient option for parents to have these made for their kids and ensure protection against the sun.

Cons

Limited Protection
Yes, these lenses do provide protection against the harmful sun's rays, but they do not provide any protection at night, especially, from the high beams of spot lights of other vehicles. At such a time, many drivers prefer to use blue lenses because they provide for equal protection during the day and night.

Immediate Effect
It takes about 2 minutes for the lens to change tints and become dark, so till it reaches that stage a person has to still bear the sun's rays. So also, after it becomes dark, it takes a long time to come back to the normal shade. So if a person does not want the sun-glass effect, he will have to bear with it.

Limited Usage
Transition lenses don't work in places which are already UV protected like cars and certain places, in which case, in spite of having these specialty lenses, it provides no relief.

Transition lenses are very convenient and cost-effective, but they do come with their own set of problems. So it really is up to you to decide what outweighs what and whether you want to go in for them or not.