The Development and Future of Contact Lenses
Executive
Summary
The
development and proliferation of contact lenses has become increasingly evident
in the world today. Its capabilities has far exceeded what it once possessed.
This
paper will examine the history of contact lenses since the birth of its idea in
the 1500s, specifically why and how it was created. The paper then examines the
current state of contact lenses, the developments that have been made as well
as the effectiveness in achieving the purpose it was made for. In the process,
this paper will analyse the pervasive usage of contact lenses and the
divergence from its traditional purpose leading it to where it stands/is today.
Finally, this paper would seek to uncover the prospect of contact lenses. The
future considerations of where contact lenses is headed and how it would impact
the world would be explored. These considerations relate to the following
aspects: the functions of future contact lenses, socioeconomic effects and
economic effects.
1 Introduction
Since
time immemorial, mankind has begun developing technologies in all aspects
possible. The creation of fire, tools, weapons and machines were mostly geared
towards aiding humankind in what they did or do. Some did venture into the
applications of knowledge on the human body.
These were mainly medical aspects which served to overcome diseases or sickness
suffered by humans. Many of these technologies served in prolonging the human
lifespan, but there were a handful which aimed at enhancing the human condition
by correcting defects which developed overtime. One such case was the defect of
human vision.
Ametropia
or better known as refractive error or in layman terms, image formation defects
is a common eye disorder suffered by humans. Refractive error occurs when the
eye is unable to clearly focus on the images from the outside world. The result
is blurred vision, which is sometimes so severe that it causes visual
impairment. The four most common refractive errors are myopia, hyperopia,
astigmatism and presbyopia. Myopia (nearsightedness) is the difficulty in seeing
distant objects clearly. Hyperopia (farsightedness) is the difficulty in seeing
close objects clearly. Astigmatism is the distorted vision resulting from an
irregularly curved cornea, which is the clear covering of the eyeball. Lastly,
presbyopia leads to difficulty in reading or seeing at arm's length, it is
linked to ageing and occurs almost universally. Refractive errors cannot be
prevented, but they can be diagnosed and treated with corrective glasses,
contact lenses or refractive surgery. WHO estimates that there are still 153
million people worldwide living with visual impairment due to uncorrected
refractive errors. This figure does excludes the people living with uncorrected
presbyopia, which is expected to be of a significant amount as shown by earlier
evidence. (WHO, 2013) A global estimate of 2.3 billion people suffer from poor
vision due to refractive error (Thulasiraj, Aravind, Pradhan, 2003).
Eyeglasses
and contact lenses are used mainly to correct refractive errors. They have been
used to correct the human vision for a long time. Eyeglasses have been invented
since 1285AD (Letocha, Dreyfus, 2002). However, it was not until 1508AD that
the idea of contact lens was conceived (Efron, 2010). Although the idea of the
contact lens was believed to be conceived in 1508, it was 380 years later
before contact lenses were actually fabricated and worn by people.
A
contact lens is a thin lightweight device that is placed directly onto the
cornea of the eye. It is used in for corrective, cosmetic or therapeutic
purposes. Contact lenses have various benefits for wearers, such as appearance
and practicality. Many people choose to wear contact lenses as opposed to eyeglasses
as they do not steam up, they provide a wider field of vision, and they are
more suitable for a number of sporting activities (Bedinghaus, 2009). There are
generally two categories of contact lens, soft and rigid gas permeable (RGP)
contact lens (FDA, 2013). These two categories will be further explored in the
later stages. Basically, they differ according to their materials and purposes.
As suggested by their names, the soft lens has a softer texture while the RGP
contact lens has a harder, more rigid texture.
2 Historical Perspective
Many
contact lens historians credited Leonardo da Vinci with describing and
sketching the first ideas for contact lenses in 1508. They believed that his
book Codex of the Eye, Manual D, written in 1508, introduced the optical
principle underlying the contact lens. The underlying principle was the
alteration of corneal power. Indeed, Da Vinci did describe a method of directly
neutralising corneal power, by submerging the head in a bowl of water (figure
1). However, Da Vinci did not mention of any mechanism or device for correcting
vision, instead he was primarily interested in learning about the mechanisms of
accommodation of the eye (Heitz and Enoch, 1987, as cited in Efron, 2010).
Years
after, a number of others illustrated theories in relation to the underlying
principle of directly altering corneal power. In 1636, Rene Descartes described
a glass fluid-filled tube which was to be placed in direct contact with the
cornea. Though it was aimed at altering corneal power, the theory was
impractical as it made blinking impossible (Efron, 2010). Then in 1801, Thomas
Young ran a series of experiments, constructing a device similar to the one
described by Descartes. He constructed a device that was essentially a
fluid-filled eyecup that fitted snugly into the orbital rim (Young, 1801). The
device was somewhat more practical in that it could be held in place with a
headband and blinking was possible, but the device was created with regards to
the mechanisms of accommodation and not for the correction of refractive
errors. Later in 1845, Sir John Herschel suggested two possible methods of
correcting critical cases of irregular cornea in the 1845 edition of
Encyclopedia Metropolitana. The first method was the application of a spherical
capsule of glass, filled with animal jelly, to the cornea, while the second
method consisted of impressing a mould of the cornea on some transparent medium
(Herschel, 1845, as cited in Efron, 2010). Although Herschel did not conduct
such experiments, his theories were adopted some 40 years later by inventors
unbeknown to each other and who were all apparently unaware of Herschel’s writings
(Efron, 2010).
During
the late 1880s, there was extensive research on contact lens which led to the
debate as to who first successfully fitted the contact lens. It was believed
that Adolf Eugene Fick, a German ophthalmologist working in Zurich, was the
first to illustrate the process of frabricating and fitting of the contact
lens. In 1888, he illustrated the fitting of a focal scleral contacts shells
first on rabbits, then on himself and finally on a small group of volunteer patients
(Efron and Pearson, 1988). On the other hand, in 1889, August Muller who was a
student at Kiel University in Germany, was credited for the fitting of the
first powered contact lens. He managed to correct his own high myopia with a
powered scleral contact lens (Efron, 2010).
From
1936 to 1974, further developments were made on contact lenses. These
developments involved the introduction of new materials of transparent plastic
(polymethyl methacrylate: PMMA), and silicone elastomer. Then after lenses were
separated into rigid or hard lens and soft lens. At that point of time, PMMA
was used to make rigid lens, while silicone elastomer was used for soft lens. Changes
in materials were due to limitations of each material, such as impermeability
to gases in PMMA and the hydrophobic surface of silicone elastomer. These
limitations have to be treated to allow effective and comfortable wear.
Eventually, they were solved with the introduction of new materials.
Advancement in technologies allowed incorporation of materials and for lenses
to be made from new materials. This allowed the previously impermeable to gas
nature of PMMA to transform into a permeable to gas nature. Substances such as
silicone, styrene and fluorine were incorporated into the rigid material of
PMMA for the transformation to occur. For the soft lens, hydrophilic gels,
specifically hydroxyethyl methacrylate (HEMA) was introduced as a new substance
used to manufacture lens. Its enhanced biocompatibility and comfort, as
compared to silicone elastomer, made it a success. During this period,scleral
lenses, which rest on parts of the sclera, were also modified into relatively smaller
corneal lenses, which covers only the cornea (Efron, 2010).
Nonetheless
after the developments made in soft, patients still suffered from severe eye
reactions after prolong usage of the same pair of lenses. Lens deterioration
over time was a major impediment to successful long term lens wear. Moreover,
the high unit cost of lenses made regular lens replacements unfeasible.
Subsequently, a group of Danish clinicians and engineers, led by
ophthalmologist Michael Bay, developed a moulding process so that low-cost,
multiple individual lens packs could be produced (Mertz, 1997, as cited in
Efron, 2010). This product was known as Danalens. In 1988, Danalens’s packaging
system and moulding technology was further refined and the result was the
Acuvue lens. Acuvue lens is an inexpensive replacement extended-wear lens. Still,
the concept of contact lenses suffered from hypoxic lens-related problems,
which severely limited the clinical utility of contact lenses, especially for
extended wear (Efron, 2010).
A
decade later, silicone hydrogel lenses were introduced into the market. This
was a significant advancement in contact lens material technology, solving the long
frustrating problems related to hypoxic lens. Within a decade, all major
contact lens manufacturers have adopted the silicone hydrogel material and introduced
silicone hydrogel lenses (Efron, 2010).
It
can be seen that the developments of contact lens in the past were focused on
getting the right material for the manufacture of contact lenses. The materials
had to allow high oxygen permeability and be biocompatible with our eyes,
providing us comfort and safety. In addition, the main purpose of contact lens
was to correct the vision of our eyes by altering corneal power.
3 Current Situation
In
the year 2012, the number of people wearing contact lenses worldwide was an
estimated 125million. Contact lens wearers had an average age of 31 years old and
67% of wearers were female (NEI, 2012). Interestingly enough the current
purposes of contact lens are reflected in these statistics. In the present
world today, contact lenses are used for various purposes, not just for the
correcting of vision through altering corneal power anymore. This section will
explore the other forms of usage of contact lens, its therapeutic purposes and its
aesthetic purposes respectively.
3.1 Other Medical Purposes
Besides
correcting vision through the alteration of corneal power, currently contact
lenses are also used to meet other medical objectives, such as prevention or
delay of diseases and providing aid to people suffering from colour blindness. In
recent years, researchers have developed UV-blocking contact lens in a bid to
reduce UV radiation entering our eyes. One benefit of minimising UV radiation
to the eyes is reducing the risk of age-related macular degeneration.
Age-related macular degeneration is a major cause of severe vision loss for
people over the age of 55. Past research have suggested that maintaining a
higher level of macular pigment appears to have a protective effect
against age-related macular degeneration. According to a study presented
at the 2012 British Contact Lens Association Clinical Conference, UV-blocking
contact lens has the ability to maintain the eye’s macular pigment density (Johnson
& Johnson Vision Care, Inc., 2012). Hence UV-blocking contact lens could be
used to delay age-related macular degeneration. UV radiation could cause many
other diseases in eyes as well, the more common ones are photokeratitis –
sunburn of the eye, cataracts and cancer in the eyeball (Woerner, 2013). The
use of sunglasses have been able to protect the eyes from UV radiation, but
UV-blocking contact lens provides additional protection from this radiation.
UV-blocking contact lens is able to absorb UV radiation from coming from all
angles, including angles not covered by sunglasses. Moreover, these lens would provide
all day UV protection, as people would normally wear their contact lens
throughout the day as compared to sunglasses which are taken off when they are
not needed. Furthermore, scientist from the Institute for Bioengineering
and Nanotechnology (IBN) in Singapore have developed contact lenses that darken
in response to ultraviolet light. These lenses contain photochromic dyes
comprising of particles that change shape under UV light, hence becoming darker
which protects the eyes from UV rays (Scott, 2009). With the introduction of
UV-blocking contact lenses these eye diseases would be further prevented and
delayed in human beings.
Another
objective of contact lenses is to aid the colour blind. The X-Chrom lens, a
monocular corneal contact lens have been developed to do so. It significantly
enhances colour perception for those who suffer from the colour deficiency. For
instance, a colour blind person would wear a deep red tinted X-Chrom contact
lens in the nondominant eye in order to intensify the colour of red and green
(Art Optical Contact Lens, Inc., n.d.). One shortcoming, is that it does not
cure the vision problem of colour deficiency, but only facilitates better
colour differentiation.
3.2 Therapeutic Purpose
Therapeutic
purposes can also be linked to medical usage of contact lenses. Therapeutic
usage of contact lens include bandage contact lens and contact lens that
deliver drugs to the eye. When people suffer from corneal damage due to eye
disease or injury bandage contact lenses are used to promote healing and reduce
discomfort. They protect the eye from external assault and also isolate the
corneal surface from friction during blinking. Bandage contact lenses are also
used after eye surgery, as they allow for easy installation of medication as
compared to other protective barriers. Additionally, they act as a reservoir
for medications, increasing the amount of time the medication stays in contact with
the eye (Trattler, n.d.). Eye drops account for 90 percent of all eye
medication, but they are inefficient. Doctors estimate that only up to 7
percent of the eye drop medication is actually absorbed into the eye. The other
93 percent flows out of the eye and drips down the cheeks. More often than not,
patients tend to forget or avoid taking their eye drop medications as it is a
hassle. Drug-dispensing contact lenses serve to solve these problems. Recently,
researchers have created a contact lens that is able to deliver a high concentration
of antibiotic at a constant rate for more than 30 days. The drug-dispensing
contact lens would not affect the wearer’s vision, because the drug containing
portion of the lens is shaped like a doughnut (Figure 2) (Leggett, 2009). With
this invention, many eye related medication can be replaced or complemented
with it.
3.3 Cosmetic Lenses
The
rise of cosmetic contact lenses is becoming increasingly prominent. Nowadays,
contact lens wearers tend to purchase tinted contact lenses to beautify
themselves. Even people who need not wear contact lens do purchase zero-powered
cosmetic contact lenses for aesthetic purposes. Cosmetic lenses can be
customised to individualise look or enhance performance. Cosmetic contact
lenses are effective in changing eye colour and appearance. They may be used in
several therapeutic applications such as masking disfigured eyes (The British
Contact Lens Association, n.d.). Other applications involve personal grooming,
the movie making industry and professional athletes. In the sports sector,
colour tinted lenses are used to increase visual performance. These lenses reduce
glare, enhance contrast sensitivity and heighten depth perception. For example,
a green tint lens can enable a tennis player to see the ball more clearly on
the court (Surtenich, 2013). On another note, an Indian optometrist has went a
step further in making contact lens as an accessory. Chandrashekhar Chawan
created the world’s first contact lenses embedded with diamonds and gold
(Figure 3). The lens is designed in such a way that it would not stop oxygen
from getting to the eye and can be customised to correct any visual
impairment. It is also said to be comfortable to wear, with the lens being able
to hold water in front of the cornea to soothe the eye (Scott, 2011).
3.4 Limitations
Generally,
contact lens pose a serious threat to the eyes without proper use and
supervision. Contact lenses can cause eye irritations or infections, if not
treated in time it could lead to blindness. For example, fungal eye infection
is possible with the usage of contact lenses. This condition can lead to
blindness and include symptoms like blurry vision, pain or redness, increased
sensitivity to light and excessive discharge from the eye (NBC News, 2006). Swimming
with contact lens is also a danger. In fact, the United States Food and Drug
Administration recommends that contact lenses should not be exposed to any kind
of water, including water in swimming pools, showers and tap water (Surtenich,
2012). This is because water could be home to countless of viruses and
dangerous microbes, which could potentially infect the eye and cause blindness.
In order to minimize chances of such conditions contact lens users should maintain
high hygiene standards, follow medical advises and seek regular medical
checkups from their eye doctor.
Contact
lenses are also not made readily available globally. As the usage of contact
lens requires supervision by professionals and certain technologies to do so,
less developed countries often have little or minimal availability of contact
lenses. Some contact lenses can also be quite costly itself. Even if more
affordable contact lenses such as cosmetic lens are made available to less
developed countries, professionals and proper eye care material would be needed
to educate and facilitate the usage of lenses. Hence, the current distribution
of contact lenses is limited to the more affluent societies and less developed
societies are unable to utilise this technology.
4 Future Considerations
Projecting
into the future, the acceleration in the development of contact lenses could
herald an age of revolutionary change. There are immense amount of
possibilities with research and innovation being done on an equipment the size
of a fingertip. Contact lenses could literally change the vision of the whole
world. This section examines the considerations which the author believes might
arise in the future if contact lenses were to be further developed and adopted
on a massive scale.
4.1 Lenses of the Future
The
possibility of having bionic eyes with the ability to zoom in on a distant
object and project virtual displays seem surreal. Yet, for the first time a
group of engineers at University of Washington have created a biologically safe
contact lens with an imprinted electronic circuit and lights. A completed lens
was said to have the display superimposed on the outside world. The engineers
tested the lenses on rabbits and no adverse effects were shown by the animals (Moskowitz,
2008).
The
lens served as a step towards the development of bionic lens in the future,
showing that the idea is feasible. If bionic lenses are indeed created in the
future, it would yield a plethora of possibilities. The author believes that
the successful innovation of this technology in the future would simplify
processes by incorporating various purposes into it. People no longer have to
carry around communication devices or even a laptop, the functions would be
projected on a midair virtual display screen that only the user would be able
to view. Of course this would require the combination of several technologies,
maybe even some which are not in the market yet. The army could utilise the
lenses to simulate training, in turn reducing the resources needed for
trainings. Perhaps, drivers could even see their route plotted on the
windshield. At that point of time the use of Google Glasses would be irrelevant
being superseded by the advantages of lenses. The future could be a time where
contact lenses exerts its dominance globally, where owning a pair of lenses
becomes a necessity.
Contact
lenses of the future might also eliminate or at least significantly reduce the
occurrences of many eye diseases. Presently, contact lenses already do so much
in the medical field as elaborated earlier in the previous sections. All the
more in the future, advance developments would be made and contact lenses could
aid those visually impaired, possibly helping them gain some sight. In
addition, it could help detect eye diseases early on without the need to visit
the doctor. For example, the lenses could be designed to observe eye conditions
and identify irregularities, so eye disease like glaucoma which symptoms do not
normally appear early on can be detected earlier on and treated before the dire
effects takes its toll on the person.
4.2 Socioeconomic Effects
The
author believes that another future consideration on the development of contact
lens would be the socioeconomic impact on the world. The prices of contact
lenses of the future might bring about significant inequality worldwide.
Currently,
not all types of lenses are at affordable prices. For example, orthokeratology
lens which corrects refractive errors of the eye costs a few hundred dollars per
piece. Furthermore, the price of purchasing a technology similar to bionic
lenses, the Google Glasses, presently costs US$1,500 per pair. With the use of
advanced technologies and intricate manufacturing process, the price of bionic
lenses in the future would be considered astronomical by the less affluent. The
author submits a scenario that future contact lenses, such as the bionic
contact lens, could be made a product which marks or exemplifies the social
status of the more affluent. Now, products like apparels and accessories are
already being used to symbolise the status of the rich. In the future, contact lens
companies could control the price or distribution of bionic lens making it
exclusively available only to those who can afford or deserve it. Hence, only
the rich and powerful could utilise this particular technology, while the rest
would be at a disadvantaged lacking the technology and possibilities it could
bring.
On
the other hand, overtime with the advancement of technologies, the
manufacturing process might be made more efficient and simplified, leading to a
reduction in cost. Governments can also implement policies to promote competition
in the contact lens industry, which encourages technology advancement and
reducing cost at the same time. Therefore, there might come a time when future
lenses are made affordable even to the less affluent. This would allow people
of all financial status to utilise the available technology.
4.3 Economical Effects
The
author believes that with the imminent rise of the functions of the contact
lens, the contact lens industry could be expanded and evolved. As of 2012, an
estimated of only 125 million out of 7 billion people in the world wear contact
lenses (NEI, 2012). If every person in the world wore contact lens the market
would be expanded by 56 times. In the future, the market of contact lens is
bound to be even large, as the population of the world continues to grow.
In
the future, with a substantial increase in functions of contact lenses its use
would be made more relevant to the world. The author depicts that if contact
lenses do one day replace communication devices, maybe even some electronic
devices, the use of contact lens would be necessary for all. The market of
contact lenses would be collaborated with all other communication devices and
electronic devices, possibly making it one of the biggest industries in the
world. In addition, the product could have so many variations that it could
evolve into an industry similar to the phone industry. Contact lenses could be
classified into different types and models, with companies competing to produce
better models into the market. The expansion of the contact lens industry, would
create countless of jobs and increase trade globally. With a considerable
amount of economic activities originating from contact lenses, it could be one
of the drivers of economic progress in countries.
5 Conclusion
This paper has examined the transformation of contact lens overtime. The original concept and purpose of contact lens served as a foundation for this finger-tip sized technology.
The
advancement in technology has amplified its capabilities and made contact
lenses safer to wear. Though there are limitations to the uses of contact lens,
many still utilise it and future developments could possibly solve them. The
author believes that humankind has only scrapped the surface of potential of
contact lenses. With the advancement in technologies and growing concepts,
contact lens could one day be a dominant technology of the world.
