When you’re on the search for affordable glasses near me from places like Dr. Tavel, you might have become curious about how they were made. If you’ve ever thought about the process of making eyeglass lenses, read on!
A Brief History of Prescription Glasses
Where and when eyeglasses originated is a bit hazy, though Greek texts have described reading optics way back in the 9th and 10th centuries.
Throughout the next hundreds of years, eyeglasses were exported across Europe, with technology improving over time. Technologies like bifocals astigmatism lenses, contact lenses, among other innovations were introduced.
Today, glasses are a fashion statement and necessity to many, coming in various colors, shapes, and sizes.
How are Modern Lenses Made?
Obviously, your eye doctor in Bloomington IN (or wherever you live) won’t prescribe you stone or crystal lenses as people wore back in the day!
Now, modern prescription glasses are durable, lightweight, and even more accessible to the general public compared to before. The process of creating prescription lenses begins in the optometrist’s office. The patient will have to undergo an eye exam for the optometrist to determine their grade ad prescription.
Depending on the prescription, the lenses would be ground, beveled, then edged into the size and shape needed to improve vision.
Optical prescriptions would have values like the following:
- Axis: Orientation of astigmatism
- Spherical base strength: Positive or negative value that measure whether a person is nearsighted or farsighted
- Cylinder base strength: Positive or negative value that measures one’s degree of astigmatism
Lens Blank Crafting
Finished lenses would start off as a lens blank, which is a piece of glass or polycarbonate plastic as big as a circular coaster.
One of the lens blank’s sides would have a curvature while the other side is flat. Technicians would choose a lens blank that have the proper amount of curvature to correspond with the patient’s particular prescription.
With a lensometer, the lens blanks will be marked at their optical center, meaning the exact point that’s over the patient’s pupil. Afterward, the lenses are affixed using adhesive tape, which prevents the lenses from scratches throughout the blocking and grinding process.
The lens will be placed in a generator, also known as a grinding machine, so the lens’ flat side will be ground into proper shape. Once the lens is curved correctly, it will go through various beveling, polishing, and sterilizing treatments, using a fining machine and other tools. The block and tape would also be removed by hand while the treatments are done.
The last step is edging, which is done through an edge grinder. The machine will grind lenses into its final and correct shape, placing a bevel around the edges for them to fit into the chosen frame. After dipping the lenses in a coat of tint and UV treatment, if needed, they will then be placed in a frame and given to the patient.
Wrapping It Up
Hopefully, you learned a lot about how eyeglasses are made and that it satisfied your curiosity!