Glasses Lenses are Not One Size Fits All: Understanding Your Options

MICHAEL COLE, OD Child and Family Eye Care Center

Glasses come in all different shapes and sizes. Frame trends come and go, colors range from bold to conservative, and they are often the first thing noticed when meeting someone. While frames vary widely, they are but placeholders for the most important part: the lenses! While the lenses in glasses frames may all seem the same, all lenses are not created equal. In fact, most cases of glasses troubleshooting we see in our clinic are due to poor-quality lenses purchased elsewhere. Our local shops certainly provide quality products, but not all vendors do, particularly online shops not concerned with quality control.

The first glasses were made in the 13th century with blown glass lenses. These likely would only be able to be used for reading due to the curvatures of the lenses created when the glass was blown. It must have been frustrating to use those lenses with irregular and uneven curvatures (think of the visual quality when looking through a blown glass window!). By the 1700s, Benjamin Franklin was credited with the first bifocal lens design. Since then, glasses have improved an incredible amount. Believe it or not, there exists abundant technology and research that guides modern lenses.

While early lenses were made using glass, modern materials have replaced glass in almost every case. There are many different types of plastics and polymers that are better suited for newer lens designs. Different materials have strengths and weaknesses. Some have clearer image quality, others are thinner, and others are impact resistant. Depending on patient needs, glasses prescription, and frame choice, some materials may be more appropriate than others. Well-trained technicians can help you decide which option will work best for your specific situation.

Older, basic lens designs are ground with a lathe and have the same curvatures across the entirety of the lens. While these lenses can now be made accurately with up-to-date equipment, there are inherent drawbacks to this method of manually grinding plastics. For example, the image quality created using this method decreases significantly when viewing away from the center of the lens. One may see clearly while looking straight ahead, but excessive head motion may be necessary to use the central portions due to poor vision through the periphery of these lenses.

Another downside of outdated designs is the image size differences created by these lenses. Depending on the prescription of the lens, eyes may appear very large or very small. Often this is noticeable enough to spot from across the room and you know that person definitely needs their glasses to see well. While this appearance is not cosmetically pleasing, this is also how these folks see the world around them — either a ballooned "coke bottle" view, or a tiny, shrunken world to navigate.

Newer, digital lens designs are customized to reduce all of these problems. Computer-aided creation of lenses allows for variable curvatures in different areas across the lens. This process allows for a much-improved visual experience. Digital lenses can be made thinner and lighter with greatly reduced minification/magnification while providing superior peripheral vision. Simply put, your lenses look better when others look at you, and you see the world much better looking through the lenses the other way as well.

Perhaps the largest leap forward in lens technology has been the addition of digital progressive lenses. Progressive lenses are often known as “no-line bifocals,” but are actually much more helpful at all viewing distances, not limited to only two like a bifocal lens. Early progressive lenses were plagued with poor peripheral vision and distortion toward the edges of lenses. Cutting-edge digital progressives provide a much more pleasing visual experience and much wider viewing areas in the near portions through the bottom of the lens.

While it may be difficult to navigate the options and customization of contemporary glasses, we would love to help ensure your needs are met in every way. If you have any questions, we invite you to please visit our clinic.