Lenses mounted on the anterior surface of the cornea, produced as an alternative to glasses to correct the refractive errors of the eye, are called contact lenses. Although contact lenses are used for optical purposes, they are a kind of prosthesis used for cosmetic and treatment purposes. Contact lenses are lenses that are placed on the corneal surface and used for correction of defects in the eye or for the treatment of some diseases.
How Should Contact Lens Application Be?
A complete eye exam is required before contact lenses are prescribed. The most suitable contact lens for the eye is decided after the consultation between the patient and the doctor. With these evaluations, it is determined whether the eye is suitable for contact lens use. It is also decided what kind of contact lens to wear.
The duration of wearing contact lenses is increased a little more every day and adaptation is achieved. This adaptation period can be 3–4 days for soft lenses and 2–4 weeks for hard lenses. During the adaptation period, there may be complaints such as watering, blinking, light sensitivity, and redness. These symptoms are usually temporary, otherwise the doctor should be informed.
What are Contact Lens Types?
Contact lenses are generally divided into two categories as soft and gas permeable hard lenses. These are gas permeable hard lenses and soft lenses. Soft lenses are mostly used, except in a few cases where the use of gas-permeable hard lenses is required.
Soft (hydrogel) Lenses
Newly developed soft contact lenses can correct all kinds of visual disorders such as hyperopia, myopia, astigmatism, presbyopia (difficulty reading near). Soft Contact lenses made of hydrophilic material that can hold water are very thin and pliable. It completely covers the cornea and protrudes into the sclera layer, which is white. There are different types. 1-day-lasting lenses used daily, 1-month-lasting lenses used daily, 3-month-lasting lenses used daily, 1-year-lasting lenses used daily, 1-week-lasting lenses used 1 week, 1-month-lasting lenses used for 1 month, used for the treatment of some eye diseases such as therapeutic lenses, bifocal lenses and colored lenses.
Hard contact lenses
It is used in all kinds of eye disorders where soft lenses are used. Especially in people with high and irregular astigmatism, it is used in people whose vision is not good with glasses due to the irregular corneal structure called keratoconus. They take this name because they allow oxygen passage to the eye, and because of these properties, they disrupt the corneal epithelial metabolism less. Since they do not take the shape of the cornea, they are especially preferred in cases such as high astigmatism and keratoconus.
A very popular lens group today is colored lenses. These lenses, which are used by those who want to change their eye color, are also available that correct visual impairment.