Since their invention almost 800 years ago, corrective lenses have been improving vision in many ways. Deteriorating eyesight affects a large part of the population and with the invention of eyeglasses, suddenly people could make out distant objects and read books clearly. The idea is simple enough and functions exactly how the lenses in our eyes do.
The Way the Human Eyes Work
The lens in the human eye is found between the optical nerves that receives the images at the retina, and the narrow opening where the light enters the eye called the iris in the cornea. The lens in the eye has a special shape that allows the cornea to focus the images, so they can be clearly defined. The clear images are then transmitted via the optic nerve to the brain where they can be interpreted.
Eye conditions begin when the lens in the eye is not focusing images properly. The problem is usually with the curve of the lens, if not properly shaped, produces fuzzy images. The problems can also be in the cornea and results in unfocused lenses. If the eye is not able to focus in distant objects, the condition is called nearsightedness. When it is difficult to focus on objects that are close up, like reading a book, the problem is known as farsightedness. Astigmatism causes distorted images to be seen.
Creating the Eyeglasses
The lenses must be created to a specific prescription in a laboratory. The glasses begin as a plastic, or glass, that is blank. These are about four inches wide by an inch thick and must be ground to the proper shape. Different sizes of blanks lens are made for the various prescriptions. The lab technician will select the blank lens for the desired prescription and place it in a machine that will grind it into its perfect form. These lenses will be thicker for improving very poor eyesight and some materials will require thicker lenses to function properly.
This process must be done perfectly, or the images seen through the lens will be distorted. Modern technology allows for this process to be done with sophisticated machinery that ensures optimal results each time. Still it is essential that the patient try the spectacles out to ensure the provide proper correction before applying to daily use.
Once the lenses have been shaped to the proper prescription, they must be shaped to fit snugly inside the frames the patient has selected. This is a process we put plenty of care into when preparing patients’ eyeglasses in Sarasota. If so desired, the lenses can be treated with photosensitive film or UV protective solution. Then a thin groove is cut along the side of the lens to allow them to sit comfortably within the frame.
Finally, the lens is placed inside the frame and fastened securely. This is sometimes accomplished by heating the frames slightly and allowing them to cool with the frames inside. The glasses will then be inspected to ensure there are no imperfections in the design. The strength and quality of the prescription will also be double checked before the glasses are polished packaged and sent to the offices of the eye doctor for delivery to the patient.
