How Do High Index Eyeglasses Work?
Like many other medical sciences, the field of optometry has made vast improvements in the last few decades. In terms of comfort, durability, and versatility, the eyeglass industry has grown in leaps and bounds – and one of the great achievements of modern optometry has been the invention and use of high index eyeglasses.
For those who aren’t familiar with the term, high index lenses are a type of lens developed to provide a high level of vision correction while still being lightweight and thin. In the past, people in need of strong vision correction had to resort to bulky, cumbersome lenses. Not so any more: now with high index lenses, even people with extremely strong prescriptions and vision problems can choose from a wide variety of lightweight and convenient lens styles.
But how can such thin lenses provide the same type of correction as the thick, heavy lenses of the past?
The main reason is the way that the lenses bend light. The reason any pair of glasses corrects your vision is because they refract light in a way that will allow your brain to interpret the messages your eyes are sending. This is what the refractive ‘index’ of a lens means – how efficiently a certain lens bends light. Therefore the meaning of ‘high index’ lenses is easy to decipher; lenses with a high index are simply more efficient at bending light than ordinary lenses.
These high index lenses are the result of many new developments in lens materials. Improvements in existing materials, blending of materials, and relatively new lens materials such as polycarbonate are all used in the creation of high index lenses. High index lenses are steadily gaining in popularity and for good reason, as there are many advantages to wearing them:
One of the main complaints of people who have to wear thick glasses is the way that they feel. Thick lenses are heavy and uncomfortable, and it’s easy for a person to get tired of wearing them. With lightweight high index lenses, you can wear your glasses all day comfortably. High index lenses are perfect for people with active lifestyles or those with hobbies – like jogging or biking – in which heavier glasses would get in the way.
Another reason many people dislike their high prescription glasses is because of the way they look. High prescription lenses have historically been noticeably more bulky and obvious than lenses with a lower prescription. Extremely thick lenses can even cause a distortion of the eye, making the eyes appear larger or smaller than they really are. High index lenses eliminate both the bulk of thick lenses, and the ‘bug-eyed’ appearance caused by them.
A couple of decades ago, those with high prescription lenses had very few choices when it came to styles and types of glasses. Today, people with any type of prescription can choose from a wide range of frame styles and colors, as well as having the option of different types of lens coatings.
With high index lenses, it’s a good idea to request an anti-reflective coating, as high index lenses tend to reflect more light than ordinary lenses. An anti-reflective (AR) coating will virtually eliminate reflected light, making your lenses crystal clear. This will also cut down on any glare you might experience when driving at night, which is definitely a plus.
High index lenses are a great choice for many people who are seeking a sleeker, more comfortable option for their strong prescription glasses. If you’re interested in high index lenses, talk to your optometrist and find out what the best options are for you.