How to Get Thinner Lenses: 4 Options to Consider
Most patients with higher prescriptions want their lenses not only to look thinner, but to also be lighter weight. Depending on your particular prescription and individual optical needs, we generally recommend one of three lens materials:
Polycarbonate is your “basic” thin, lightweight lens. Composed of a dense, plastic-like material, polycarbonate is very impact resistant. This make it great for safety eyewear, eyewear for very active individuals, and children. It is also a great option for people that may have limited or no vision out of one eye, and need to take extra precautions to protect their remaining “good” eye.
Polycarbonate, in and of itself, is not very scratch resistant. Therefore, all polycarbonate lenses are hard-coated in the lab. All of our polycarbonate lenses come with a one year scratch warranty from our lab.
It is not the best option for tinted sunglasses, because it does not tint very well (it is hard to get the tint very dark). Polarized lenses are a better option for polycarbonate sunglasses. A great feature of polycarbonate (even in their clear state) is that they are 100% UV protectant.
A final thing to think about in regards to polycarbonate is that it does not have the best optical qualities. Many people find that the slight chromatic aberrations found in the lenses is not even noticeable, but some individuals, especially those with great peripheral vision or very high prescriptions, find that their vision is better through a different lens option, such as trivex and high-index.
Trivex is one of the newest optical materials on the market. It combines the best features of polycarbonate (scratch and impact resistance, UV protection, thin, and light-weight) with the great optical qualities of CR-39 plastic and glass. What this means is that patients with higher prescriptions should experience much better optics through their lenses- especially through the peripheral portions of their lenses.
Trivex is also the best choice for drill-mounted/rimless glasses, since the lens does not exhibit the cracking or chipping around the drill holes that patients with plastic or polycarbonate may experience if their glasses are exposed to a lot of stress.
Trivex is easy to tint, and is an excellent choice for sunglasses.
One of the only downsides to trivex, because of it’s relative newness, is that there are still a few lens combinations that are unavailable (such as some styles of lined bifocals with Transitions, etc.).
Depending on the prescription, high-index lenses are one of the thinnest options available. This is an excellent option for patients with very high prescriptions.
There are a few things to be aware of with this lens option. First of all, because of how dense it is, high-index tends to create a higher level of chromatic aberrations than a plastic or trivex lens option. Also, it tends to reflect a lot more light than most other lens materials, making it almost a necessity to include an anti-reflective coating. If this coating is not selected, patients might notice a lot of distracting reflections from oncoming headlights when driving at night, fluorescent lights, TV’s, and computer monitors.
For patients with extremely high prescriptions, the slight sacrifice of optical quality may be an excellent compromise to achieve a thinner lens. Technically, high-index is a heavier material than polycarbonate or trivex lenses, but the actual weight difference between a high-index lens and a polycarbonate or trivex lens should be fairly imperceptible.
High-index is also quite impact and shatter-resistant, although they are not quite as safe as polycarbonate and trivex. This makes them an acceptable option for semi-rimless and drill-mount/rimless glasses.
A further option to consider as an upgrade to any of the above discussed lenses would be to have them made as an “aspheric lens.” There are two ways to make an eyeglass lens- either “spherical,” which is the standard method of manufacturing lenses, or “aspheric” which is a type of curvature that is not a part of a sphere or cylinder. Put in a different way, if you looked down on the front surface of an aspheric lens, it would have a minute “bullseye” pattern across the lens. Because of the unique way in which this lens is formed, it allows the lenses to be made flatter and thinner.
An additional benefit is that it reduces the distorted appearance of the patient’s eyes, as seen by a person looking at the patient through the lenses. So, for instance, a standard spherical lens in a high plus prescription would make a patient’s eyes appear much larger than they really are (just like a high minus prescription would make a patient’s eyes look much smaller than they are in actuality). An aspheric lens in this same prescription would make the patient’s eyes appear much closer to their actual size.
We hope that this article has been helpful. If you have any questions about eyeglass lenses (or any other optical topics!), just ask one of our friendly opticians! We are always happy to show you demo lenses so you can actually see what we are describing in this article.