Nepedia
Back to Discover
Advanced Reader
💻

Contact lens

technology Maturity 7-9 Next article →

Contact lenses are thin ocular prosthetic devices placed directly on the surface of the eye.

Contactlenzen Confortissimo
Contactlenzen Confortissimo

They are used by over 150 million people across the globe. People wear these lenses for several distinct reasons. Some use them for functional or optical purposes to correct vision. Others choose them for aesthetic or cosmetic reasons to change their eye color. They are also used for therapeutic reasons to treat specific eye conditions. For example, they can correct conditions like keratoconus or aniseikonia more effectively than glasses.

Eye with contact lens
Eye with contact lens

To correct vision, contact lenses work by focusing light. The lens bends light so it enters the eye with the proper power. This allows for clear vision by adjusting how light hits the retina. A spherical contact lens is a type that bends light evenly in every direction. This specific shape is used to correct myopia and hypermetropia. For patients with astigmatism, specialized toric soft lenses can be used. These lenses provide better peripheral vision than traditional eyeglasses. They also do not collect moisture from rain, snow, or perspiration.

Lens Basecurve
Lens Basecurve

There are several different types of contact lenses categorized by material and design. Scleral lenses are large shells that rest on the less sensitive rim of tissue surrounding the cornea. They float on a dextrose solution. Corneal lenses are much smaller and sit only on the cornea itself. These were developed in 1949 and could be worn for up to 16 hours a day. Rigid gas permeable, or RGP, lenses are a type of hard lens. They were developed to allow oxygen to reach the conjunctiva and cornea. Soft lenses are often made from hydrogel materials.

The history of contact lenses began with early, impractical ideas. In 1508, Leonardo da Vinci described a method to alter corneal power. He suggested submerging the head in a bowl of water. He also suggested wearing a water-filled glass hemisphere over the eye.

Da Vinci's method of corneal neutralization
Da Vinci's method of corneal neutralization

In 1801, Thomas Young created basic lenses using wax to hold water-filled lenses in place. Later, Joseph Dallos perfected a method of making molds from living eyes. This allowed lenses to conform to the actual shape of the eye. In 1888, Adolf Gaston Eugen Fick fabricated the first successful afocal scleral contact lens.

Adolf Fick-adjust
Adolf Fick-adjust

These early glass lenses were heavy and could only be worn for a few hours.

Material science changed how lenses were manufactured and worn. The development of polymethyl methacrylate, or PMMA, in the 1930s allowed for plastic scleral lenses. In 1939, Dr. István Györffy produced the first fully plastic contact lens. A major breakthrough occurred in 1959 when Czech chemists Otto Wichterle and Drahoslav Lím introduced soft hydrogel lenses.

Prof. Ing. RTDr. Otto Wichterle
Prof. Ing. RTDr. Otto Wichterle

These were much more comfortable than rigid lenses. In 1972, Rishi Agarwal suggested the idea of disposable soft contact lenses.

ColorContactLens
ColorContactLens

Later, in 1998, Ciba Vision released the first silicone hydrogel lenses in Mexico. These materials combine the comfort of hydrogels with the high oxygen permeability of silicone.

Modern lens technology continues to evolve through advanced chemistry. Second-generation silicone hydrogels use the Tanaka monomer, which was patented in 1979. This monomer helps improve the performance of lenses like Acuvue Advance. Some third-generation polymers, such as Comfilcon A, use siloxy macromers of different sizes. This combination produces very high oxygen permeability even with high water content. Other materials, like Enfilcon A, are designed to be naturally wet with a water content of 46 percent. These advancements allow for more comfortable and safer extended wear.

The contact lens industry is a massive global market. In 2023, the worldwide market was estimated at $18.6 billion. This market is expected to reach $33.8 billion by the year 2030. North America holds the largest share of this market at over 38.18 percent. The average age of a contact lens wearer is 31 years old. Additionally, two-thirds of all wearers are female. While contact lenses can cost between US$200 and US$1,000 annually, they offer unique advantages. They allow users to wear sunglasses or goggles without needing special prescription fittings.

667 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (15)
File:Contactlenzen Confortissimo.JPG
Contactlenzen Confortissimo.JPG
File:ColorContactLens.JPG
ColorContactLens.JPG
File:Da Vinci's method of corneal neutralization.jpg
Da Vinci's method of corneal neutralization.jpg
File:Adolf Fick-adjust.png
Adolf Fick-adjust.png
File:Prof. Ing. RTDr. Otto Wichterle.jpg
Prof. Ing. RTDr. Otto Wichterle.jpg
File:Contact Grain.jpg
Contact Grain.jpg
File:Scleral lens worn on an eye.jpg
Scleral lens worn on an eye.jpg
File:Eye with contact lens.jpg
Eye with contact lens.jpg
File:Lens Basecurve.jpg
Lens Basecurve.jpg
Contact Lens Wiki 2 3.webm
File:Lens-cover.jpg
Lens-cover.jpg
File:Contact lens case for Hydrogen Peroxide solution showing bubbles.jpg
Contact lens case for Hydrogen Peroxide...

+ 3 more

More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.