CR-39 is the most common form of plastic and most widely used material in prescription eyeglasses. CR-39 is a lighter option than glass and has the added benefit of not breaking as easily as a glass lens.

Glass is the oldest existing form of lenses in the eyewear industry. It's main benefit over other materials is it's resistance against scratching, however, glass lenses are more prone to shattering and are extremely heavy compared to newer aged materials.

Polycarbonate lenses are the safest option of lens materials available. Polycarbonate, a form of plastic, is far superior to any other plastic in its durability and resistance to shattering. On average Polycarbonate is 30% thinner and lighter than CR-39. This extremely strong material is used to make bullet proof windows because of its impact resistance and shatter-proof characteristics.

On average, 1.56 mid-index plastic lenses are 30% thinner and lighter when compared to CR-39 plastic lenses.

This option is for a glass lens with the added benefit of Photo Gray Xtra. Photo Gray Xtra is a feature that darkens the lenses with a gray tint when exposed to sunlight. At its darkest a Photo Gray lens will darken to 85%, and will always have a minimum 15% gray tinting even indoors.

Transition Plastic CR-39 lenses are standard CR-39 lenses with the added benefit of auto adapting tint. The degree of tint reacts based on the amount of exposure to sunlight and UV rays. Transition lenses are 100% clear while indoors and also during night time conditions. Transition lenses quickly turn into sunglasses when exposed to sunlight and block 100% of UVA and UVB rays. Indoors these lenses are perfectly clear and they will darken up to an 85% tint in direct sunlight. Available in Gray or Brown.

This option is for a glass lens with the added benefit of Photo Brown Xtra. Photo Brown Xtra is a feature that darkens the lenses with a Brown tint when exposed to sunlight. At it's darkest, a Photo Brown lens will darken to 85%, and will always have a minimum 15% brown tinting even indoors.

This option is the ultimate form of protection and comfort when lenses will be used as sunglass lenses only. This lens is a CR-39 plastic lens with polarization. Polarized lenses never fade and block horizontal light, resulting in the reduction of glare. Polarized lenses block 100% of the sun's harmful UVA and UVB rays. The clarity, comfort, and protection that Polarized lenses provide is far better than any other option available for sunglass lenses. This option is highly recommended to anyone with sensitivity to sunlight and/or glare. Polarized lenses are available in Gray or Brown.

On average 1.67 high-index plastic lenses are 50% thinner and lighter when compared to CR-39 plastic lenses.

This option gives you the benefit of both Polycarbonate light weight, shatter-proof lenses with the added convenience of a the auto-adapting tint offered by Transitions. Available in Gray or Brown.

This option gives you the benefit of both comfort and protection that polarized lenses provide from the sun's strong glare and harmful UV rays as well as the unsurpassed strength and safety provided by lightweight Polycarbonate lenses.

This option is for standard CR-39 plastic lenses with the Drivewear feature. Drivewear is a unique combination of Transitions photochromic technology and NuPolar polarization. These lenses are ideal for conditions such as overcast weather, normal driving conditions, and bright outdoor light. The added benefit of this lens over standard Transitions lenses is that they remain dark while driving inside the car. These lenses will have a constant 50% tint indoors.

This option gives you the benefit of a thinner, 1.56 mid-index light weight lenses as well as the added convenience of a the auto-adapting tint offered by Transitions. Available in Gray or Brown.

This option gives you the benefit of super thin 1.67 high-index, light weight lenses as well as the added convenience of a the auto-adapting tint offered by Transitions. Available in Gray or Brown.

This option gives you the benefit of maximum strength and safety provided by polycarbonate lenses as well as the convenience and versatility of Drivewear technology.

This option gives you the benefit of both comfort and protection that polarized lenses provide from the sun's strong glare and harmful UV rays as well as the benefits of super thin, high-index 1.67 light weight lenses.

Used for all-purpose, everyday wear such as driving, watching TV, etc...

Used for reading, sewing, and other close-up activities not including computer work. Single Vision Computer lens also available, please specify "For Computer Use" under comment section at the end of checkout.

Used for both distance and near vision. The top of the lens is used for distance while the bottom of the lens is used for reading. A 28 millimeter visible line is used to separate the distance and near vision sections.

Used for both distance and near vision. The top of the lens is used for distance while the wider bifocal portion at the bottom of the lens is used for reading. A 35 millimeter visible line is used to separate the distance and near vision sections.

Used for all ranges of vision including far distance, intermediate (computer), and reading distances. Two visible 28 millimeter lines separate all three fields of vision, with the intermediate segment 7 millimeters tall.

Used for vision at all distances. This is also referred to as a no-line bifocal. This lens does NOT have visible lines separating the different fields of vision.

By choosing this option, you will receive the frame complete with the manufacturer's non-prescription demo lenses.

By choosing this option, you would like to have high-quality, non-corrective lenses put into the frame to be used for fashion use only.

The first number refers to the width of the lenses individually at the widest points. The middle number refers to the width of the bridge connecting both lenses, while the last number refers to the length of the arms from the hinge to the end of the temple. All three numbers are  always represented in millimeters.