It is estimated that about 75 per cent of the population needs some kind of vision correction and therefore wears glasses. Eye problems can start very early in life and people of all age groups can have the need to wear spectacles. Some wear glasses to read, others wear them to drive, while still others need glasses only as they grow older. Advancement in technology has led to spectacles being made of better, lighter and more durable materials. However, glasses were and are still considered a fashion hindrance as they cover a part of the face. They are also seen to be a nuisance and an inconvenience. Corrective surgery was and is one alternative to wearing glasses. However, not everyone chooses that option. Vanity and comfort played a major role in scientists working on alternatives to wearing glasses.
Tracing Back History of Contact Lenses
Scientists had begun working on the most basic contact lenses as far back as the 1800s. However it was only in 1949 that the first ‘corneal’ lenses were developed. These were much smaller than the original scleral lenses developed in the 1800s and could be placed on the cornea of the eye rather than the entire visible ocular surface. They also had a longer shelf life and could be worn up to 16 hours a day. These corneal lenses became hugely popular with people who wore glasses and started to gain popularity in the 1960s. This was coupled further with better lens designs and became more sophisticated, comfortable and wearable with improving manufacturing technology.
Early corneal lenses in the 1950s and 1960s were relatively expensive and fragile and continued to be refined through the decades. One of the biggest disadvantages of these lenses was that no oxygen was transmitted through the lens to the conjunctiva and cornea, which caused a number of adverse clinical effects. This also made prolonged use uncomfortable and led to dryness and discomfort in the eyes. By the end of the 1970s, and through the 1980s and 1990s, a range of oxygen-permeable but rigid materials were developed to overcome this problem. Chemist Norman Gaylord played a prominent role in the development of these newer, permeable contact lenses. All modern contact lenses that allow oxygen to permeate through are based on these lenses.
So popular were contact lenses that work continued on them to make them even more comfortable and convenient. A major breakthrough in this regard was made by Czech chemists Otto Wichterle and Drahoslav Lim. Their paper on contact lenses and their use called ‘Hydrophilic Gels for Biological Use’ was first published in the journal Nature in 1959. They worked on creating the world’s first soft contact lens. These lenses were soon prescribed more often than rigid lenses, primarily due to the immediate, comparative comfort of soft lenses. In contrast, rigid lenses needed some time to be set comfortably on the cornea. Soft lenses fitted better to the contours of the eye, making them much more comfortable. Most importantly, the polymers from which soft lenses are manufactured improved over the next 25 years, largely in terms of increasing oxygen permeability. In 1972, British optometrist Rishi Agarwal came up with the practical idea of disposable soft contact lenses. This idea caught on fast and scientists began work on lenses that would have different time frames and shelf lives. Spherical contact lenses that bend light uniformly in every direction were also developed. They are primarily used to correct myopia and hyperopia.
One of the most convenient and important breakthroughs in contact lens manufacturing was the daily wear contact lens. Unlike the regular ‘extended wear’ (EW) contact lens which was designed for continuous wear, the daily contact lens can be worn and disposed off every day. Better technology made it easy for people to choose the kind of lens they wanted to wear – daily wear lenses that last up to a week, a month or even a year.
Pros of Contact Lenses
Corrective contact lenses, an alternative to glasses, were designed to improve vision, most commonly by correcting the refractive error in the eyes. They can be classified by function, type of material, time frame and shelf-life. Contact lenses also help in correcting certain colour deficiencies. For this purpose a red-tinted ‘X-Chrom’ contact lens is used. These do not completely repair problems associated with seeing a lack of colour, but they help people in distinguishing colours more easily.
Soft contact lenses are also used in the treatment and management of non-refractive disorders of the eye. An injured or diseased cornea can be protected from germs and constant rubbing of blinking eyelids, which makes healing faster and safer. They are also used in the treatment of eye conditions like bullous keratopathy, dry eyes, corneal abrasions and erosion, keratitis, corneal edema, descemetocele, corneal ectasis, Mooren's ulcer, anterior corneal dystrophy, and neurotrophic keratoconjunctivitis.
The Case Against The Use of Contact Lenses
There are also some common problems associated with contact lenses since they are used on the eyes, one of the most delicate parts of the body. Extended and continuous use of contact lenses, not following the proper cleaning or use schedule and improper use like sleeping while wearing them have led to some complications. In some cases this has led to various eye-related problems like conjunctivitis, formation of fungi and bacteria and even permanent damage to the eyes. Long-term wearing of rigid contact lenses has led to other problems like decreased corneal keratocyte density and increased the number of epithelial Langerhans cells. In recent years coloured contact lenses have also served as a fashion accessory, especially amongst the youth.
The Final Word about Contact Lenses
In conclusion, it can be said that over the last century contact lenses have been one of the most important inventions for vision correction. They have also taken care of very basic human needs like convenience and the desire to look good and feel comfortable.