Contact lenses, or contacts, are made of soft gel and are commonly used as an alternative to eyeglasses. Contact lenses usually function as corrective lenses, similar to how eyeglasses are used. Later developments, however, have allowed consumers to wear contact lenses not only for therapeutic and cosmetic purposes. There are many types of contact lenses, but the commonly used classification is according to function: corrective, therapeutic, and cosmetic.
As the name implies, corrective contact lenses are used to correct and improve the wearer's vision. Most people who wear contact lenses do so to repair refraction error, or the mismatch between the eye's length and its refractive power. Contacts lenses repair this error by neutralizing the mismatch and correct the light focusing of the retina. Among the conditions reparable by corrective contact lenses are astigmatism, hypermetropia (far-sightedness), myopia (near-sightedness), and presbyopia (diminished ability to focus on nearby objects caused by aging).
Depending on the brand and makeup of the contact lenses, users usually take out their contact lenses every night or every other day. Those with colorblindness or other color vision deficiencies may also use red-tinted contact lenses called X-Chrom. While these contact lenses cannot restore and permanently repair color deficiencies, it is effective in helping colorblind individuals distinguish colors.
Therapeutic Contact Lenses
Therapeutic contact lenses are soft lenses used in managing and treating non-refractive eye disorders. Those who have recently undergone eye surgery and have increased corneal sensitivity can use bandage contact lenses to protect the cornea from the friction caused by blinking eyelids. Therapeutic contact lenses are also used in treating keratitis, dry eyes, corneal edema, bullous keratopathy, etc. Studies have also shown that contact lenses may be used to deliver and administer drugs directly to the eyes.
Cosmetic Contact Lenses
Cosmetic contact lenses are those worn and used for the sole purpose of enhancing or changing the appearance of the eyes. Some cosmetic contact lenses may also be used to correct vision, but they're not as effective because the design or color can blur or obstruct the wearer's vision. Among the different types of cosmetic contact lenses are theatrical and scleral.
Theatrical lenses are used in film and TV industry as part of character portrayal and costume. They are often used in horror movies to make the eyes look lifeless or demonic. Scleral lenses are used in theatrical lenses and are used to cover the white areas of the eyes. Scleral lenses are much smaller and are thus difficult to insert.
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