As people grow older, their eyes can change causing them to need glasses or different prescriptions to see better. There are several different types of prescription lenses that are used to sharpen focus and allow objects to be seen at further distances. Here are the types prescription lenses used to help improve eyesight.
These lenses are the most commonly prescribed lenses by opticians. They have one strength from edge to edge and are usually the first type of lenses prescribed to people who have trouble seeing objects close up, which is farsightedness, to further off, known as nearsightedness or myopia. Children and adults diagnosed with astigmatism may also be prescribed single vision lenses.
As the eyes age, they may have problems seeing objects both up close and far away. By prescribing bifocal lenses, Perth opticians can help older patients look down to read books or focus on objects farther away while driving. The powers may be separated by a line or there may be a smaller section for reading through.
These lenses allow people to focus on objects at most distances by glancing through different sections of the lens. They usually don’t have lines separating the lenses’ powers because the lines could obstruct a person’s vision. People who work with computers for most of the day often use trifocals because they allow them to focus on the screen without needing to tilt the head up or down continuously, which can result in stiff necks.
These may be used in place of bifocals or trifocals and allow vision to progress easily from strength to strength to see better. They improve near, intermediate and distance vision without interference and the need to move the head. The user just needs to glance through each different part of the lens in order to focus their vision where it is needed.
While eyeglasses were once made only from glass, they were heavy, especially if the lenses were thicker to provide better vision for the user. Aside from being heavy, glass lenses could be easily broken, which was dangerous for the wearer.
Plastic lenses were developed to correct vision with a much lighter lens. Plastic or plastic polymer lens called CR-39 are still popular today because of they are light and inexpensive. To prevent scratches, a coating was developed to help make them scratch resistant.
Polycarbonate lenses are another popular choice for children’s eyeglasses, safety and sports glasses. This material was originally used for military helmet visors and “bulletproof glass,” which was made for both security and safety applications. Along with being impact resistant, these lenses can block 100% of the ultraviolet rays from the sun.
After an eye examination, your optician will prescribe the type of lenses that you need in order to correct your vision to as close to 20/20 as possible. He or she can also recommend a material for your eyeglasses so that they are lightweight and provide the protection you need when wearing every day. They can also be tinted to provide UV protection, as well.