Contact lenses are small visual devices made with curved pieces of plastic shaped in a way to conform directly to the wearer’s eye. They provide an artificial refracting surface to the human eye and are used to correct vision problems like myopia and hypermetropia. Contact lenses aid in eye focusing in the same manner as spectacles do. Apart from these corrective measures, contact lenses can also be used for cosmetic and therapeutic reasons.
There have been many modifications and improvements to the original idea of contact lenses, conceptualized first by Leonardo Da Vinci, through centuries. About 35 million people in the U.S. wear contact lenses today.
Features of Contact Lenses:
The lenses are made from different types of materials – soft and rigid – and come in a variety of designs and colors. These include disposable, colored, astigmatic, aphakic, presbyopic and keratoconic lenses. The initial fitting and follow up care are important parts of contact lens usage to give maximum benefits of vision, appearance, comfort and tissue integrity.
Advantages of Contact Lenses:
Contact lenses are capable of correcting most of the problems that spectacles can as well as some additional ones that glasses cannot.
People not satisfied with their appearance using glasses can opt to use contact lenses for improved appearance. Contact lenses are not in the danger of slipping off, getting wet, or fogging up, which can easily happen with spectacles.
Extremely hypermetropiac people or those who have had cataracts removed, feel better wearing contact lenses as compared to spectacles, which in these cases produce uneven vision. Moreover, contact lenses give improved vision for people with damaged corneas due to disease or injury. Also for sportsmen, wearing contact lenses prove to be more practical as in the case of those where wearing spectacles pose a problem in their jobs. In addition to all these, contact lenses provide better side vision compared to glasses.
Uses of Contact Lens:
The primary use of contact lenses is to correct myopia (short sightedness). They can also be used to rectify hyperopia, astigmatism, presbyopia and aphakia. Rigid lenses are used to correct irregular corneal trauma. Soft lenses are used as bandages for conditions like bullous keratopathy, recurring corneal erosion as well as to increase comfort, vision and postoperative wound healing.
Main Types of Contact Lenses:
There are two principal types of contact lenses in use today. Soft contact lenses are those that are made of hydrophilic plastics and absorb liquid and must be kept moist for softness and easier moulding to the corneal surface. They are extremely comfortable and are used by majority of contact lens users. The other type in use is the gas permeable (RPG) or rigid contact lenses, which are composed of durable and flexible plastics, which permit oxygen to pass through to the cornea and are easier to maintain. The original hard lenses, or PMMAs, used earlier did not allow oxygen to pass to the eye and have been replaced by the RPGs.
If a person desires to use contact lenses, he or she should do so only after consultation with an ophthalmologist. He/she will advise whether contact lenses would be suitable for a person to use or which kind of lenses, soft or gas permeable, should be used in a particular case. It is imperative that a yearly examination be done after the initial use of contact lenses.