What are contact lenses?
Contact lenses can be used to correct vision disorders, change eye color or treat corneal diseases.
Contact lenses have evolved in the 1800s from blown glass lenses that completely cover the front of the pupil to thin plastic corneal lenses. Today, lens types and materials are varied with the usage options it provides.
An eye examination is performed by an ophthalmologist for the selection of contact lenses suitable for the patient’s eye structure. The lens type, diopter, base curve, and diameter to be used are determined in the examination. The same lens or a lens with the closest diopter possible is used to determine the fit. The movement, balance, and center of the lens are examined.
How to choose an appropriate contact lens?
Contact lenses are designed to be placed on the cornea. They are held in place mainly by sticking to the tear film that covers the front of the eye and a little by the pressure of the eyelids.
As the eye blinks, the eyelid slides over the surface of the contact lens, causing its front to move slightly. This action allows the tears to provide the necessary lubrication and helps to wash away the deposits.
The too tight lens will not move at all. It may cause eye sensitivity. At first, the user may be comfortable, but visual acuity is poor. It can cause complications in the long term.
The too loose lens moves excessively. The lower eyelid feels the lens a lot. After blinking, the image is blurred. The lens is off-center. Lens edges can be bent.
What should be considered when using contact lenses?
Features of contact lenses
The larger bace curve is flat and is called FLAT. The smaller bace curve is curved and is called STEEP.
Diameter: It is the mm measurement taken from the outermost edge to the other edge in the center of the lens. Diameter affects the fit of the lens to the eye. For soft lenses, these values are between 13.5 / 14.5 mm, for hard lenses is 7 mm.
We use cookies so that you can make the most of our services. By logging into www.dunyagoz.com, you are deemed to have accepted the use of cookies.
Learn More