Types of Lenses for Prescription Safety Glasses

Your lens material can have a major impact on your other lens options, and vice versa.

Prescription and Safety Glasses and Lens Material Options

Prescription Safety LensesWhen ordering a pair of prescription safety glasses, your lens material has a large impact on both your other lens option choices and some of the traits of your lenses. If you are shopping for prescription glasses online, it’s important to familiarize yourself with the different lens materials offered, their strengths and weaknesses, and their availability in different colors and prescriptions. Doing so will make shopping easier and more productive.

Plastic, polycarbonate, high index plastic, and trivex lens materials can all be considered types of plastic. The other materials typically available are glass and, to a much lesser extent, high index glass. Knowing which materials are best for what types of glasses will make it easier to narrow down your choices based on the kind of prescription glasses you’re hoping to get. Even if you are still faced with deciding between two or three lens materials, it will be easier than deciding between six of them.

Here is some useful information about lens materials for prescription glasses:

  • The index of a lens relates to its ability to efficiently bend light. The higher the index, the thinner your lens can be to accommodate the same prescription. Also, higher indexes are generally more scratch resistant but less optically clear. You sacrifice some optical clarity to get your lenses thinner and lighter, generally speaking.
  • Standard plastic is a low-index plastic material that is fairly scratch resistant and easy to make in prescription. It is generally the cheapest lens material and is available in any lens color including Transitions, polarized, tinted, and clear. This is a good choice for low-power prescriptions (between -2.00 and +2.00), especially if you’re looking to get a lot of upgrades. These lenses are fairly optically sound.
  • High index plastic is typically more scratch resistant than standard plastic, and it is definitely thinner. It offers the thinness, light weight, and lack of eye distortion (where your eye look bigger or smaller to others looking at you). Its downsides are its high cost, relatively high optical distortion, and low availability in several lens colors and prescription types. High index is harder to find as a lined bifocal and in a polarized lens color, though it can be tinted.
  • Polycarbonate is a medium-index material between standard and high index plastic. It is very easily scratched, but it is also very impact resistant. Polycarbonate is available in almost every combination of prescription and lens color that standard plastic is, with a few very specific exceptions which are not worth noting. Polycarbonate has more optical distortion than standard plastic, but less or as much as high index plastic. It is typically used for medium- to low-power prescriptions (between -5.00 and +4.00) and it is almost always used when making prescription safety glasses. We recommend this above all other for safety due to its impact resistance.
  • Trivex is a less common synthetic polymer that shares characteristics of polycarbonate and standard plastic. It is almost as impact resistant as polycarbonate, but it has higher optical clarity and better scratch resistance. This material has become more popular in recent years and, while it is not available in many lens colors and prescription combinations, it is working its way to being as customizable as poly or plastic.
  • Glass is the most scratch resistant lens material, but it is obviously more brittle than plastic and easier to break. It has a medium index and high optical clarity. This is not a good choice for safety, generally, but it is good when you are looking for glasses that will never need to be impact resistant but should be very scratch resistant. In general, we do not recommend glass for safety because most safety situations involve some amount of impact hazards. Glass is hard to find in polarized colors and it is not tintable.
  • High index glass shares all the characteristics of standard glass, but high index is more thinner and lighter. It is also more brittle, has the worst optical clarity, and is much easier to break. We do not recommend or offer high index glass as it is only a good choice for a very few people, and never a good choice for safety.

When shopping for prescription safety glasses online, it is most important to consider the types of hazards you need to protect yourself from. If you need impact resistance, nothing will protect you as well as polycarbonate. That being said, if scratch resistance is very important to you, you may want to choose plastic instead. Most of our customers choose polycarbonate and, when cared for correctly, find that poly lasts until they need a new pair of glasses.

If you are curious about what lens materials are best for your application, the best thing you can do is call. Our customer service representatives have knowledge of the best choices for most applications, along with helpful tips for how to extend the life of your glasses.

One of the most important things you can do is to clean your glasses well. You can overcome the relatively low scratch resistance of polycarbonate simply by using tap water to rinse the debris off of the glasses before cleaning them. You should also never use cleaning solutions with ammonia in them on polycarbonate as it can ruin the lenses. Lens coatings have their own set of rules as well.

For more information about lens materials, drop us a comment below or give us a call. We’d love to know what lenses you chose and why!

Written by Kieran Hunt

Kieran Hunt is the staff writer and product research engineer at RxSafety. Kieran writes a majority of the company's written content while also working with the company's owners to develop new prescription safety glasses.Website: http://rx-safety.com

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