About Contact Lenses

Definition

Contact Lens
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The primary function of all contact lenses is to correct our vision. There are three broad types of contact lenses available:

  1. Corrective:
    2. Technological development has created new methods to correct refraction error. An example would be the development of orthokeratology, which enables correction of myopia using contact lens by deliberate overnight flattening of the cornea. The temporary corrected cornea allows the wearer to have corrected vision for the day. Also there are contact lenses such as the red-tinted "X-Chrom" that aid people with color deficiencies.


    Contact Lens
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  2. Cosmetic:
    3. Apart from correcting vision, cosmetic lenses are designed to change the appearance of the iris color and size.

  3. Therapeutic:
    4. Therapeutic lenses are used to treat non-refractive disorders of the eye such as corneal ulcer and keratitis.

History

Leonardo da Vinci's early sketch
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Invention of contact lenses starts from 1508 where Leonardo Da Vinci came up with drawings and descriptions of contact lens in his study of mechanisms of accommodating the eye. Over the years, the material of contact lenses changed from glass to plastic and now, the most common type of contact lens is the soft contact lenses.

For more information about the history of contact lenses, you can visit

Advantages & Disadvantages


Advantages

Contact lenses move with the eyeball, allowing a natural field of view and better peripheral vision. There are also no obstructions or reflections in view unlike spectacles. These characteristics are especially important in sports and driving whereby one needs to maximize his view and minimize distractions. Hence making contact lenses an essential invention for athletes with vision errors to improve their performance and to cater to different needs. Features like disposability and extended wear have also been added to contact lenses.

Disadvantages


Fungal Infection
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Apart from the various benefits there are also disadvantages of contact lenses. For example, contact lenses require special care. The user must spend time and effort to keep the contact lenses clean. There are several complications that may arise due to improper care and wearing of contact lenses. One significant complication would be fungal infection, which will lead to blindness.
Quoted from "Prevention better than care"

Comparison of Lenses

Different Lenses Cost Fragility & risk of contamination Comfort & adaptation Oxygen transmission to cornea Disposable Extended-wear
Rigid Gas Permeable Lens Affordable Low Comfortable and require a long adaptation period Very adequate Daily, Weekly, Monthly Up to 30 days
Disposable Soft Contact Lens Cheap High Comfortable and only require a short adaptation period Adequate Daily, Weekly, Monthly Up to 30 days
Hard Contact Lens Cheap Corneal irritation and abrasion Low comfort and require a long adaptation period Inadequate No No

Quoted from "Contact Lenses Club"

Future for Contact Lenses


Future
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A future contact lens idea that seems promising originated at the University of Florida, where researchers have developed "drug-laden" lenses to deliver medication at precise intervals. These soft contact lenses were developed for people suffering from glaucoma or other eye disorders. They use tiny drug-filled "nanoparticles" capable of releasing medication slowly and steadily into the eye. These lenses would be a lot more efficient than regular eye drops, which tend to release most of their medication into the bloodstream and not the actual eye where it is most needed.
Quoted from "Contact Lenses of the Future"

For more information about the impact and future of contact lenses, you can visit