Introduced at the end of the 1880s, the first contact lenses were large, rigid and complicated to make and insert. Many patients could only bear to wear them for a couple of hours before the irritation became too great. The drawn out fitting procedure and need to maintain proper hygiene was both expensive and inconvenient and disincentivised greater uptake. The first functional contact lenses were created using blown glass to cover the entire eye. Over time they reduced in size so as to cover just the cornea, until the invention of new materials negated the need to minimise the amount of contact.

Throughout the 20th century, contact lenses evolved dramatically, from the heavy, uncomfortable glass lenses to lighter plastic versions introduced in the 1930s and increasingly breathable polymers from the 1960s onwards. Although hailed as the death knell for spectacles, from at least the 1950s, contact lenses ('hidden' or 'invisible glasses') remained a minority choice and a specialist area of practice where optometry and ophthalmology overlapped. That was until the introduction of disposable contact lenses in the 1980s led to them becoming far more popular, among spectacle wearers and non-spectacle wearers alike.

The cornea is that part of the front surface of the eye through which the light passes. The way the light is bent (refracted) within the eyeball is affected by the corneal shape. A vision aid, such as a spectacle lens held or worn in front of the eye, may overcome, or neutralise, this effect, leading to clearer vision in patients whose corneas may not be an ideal shape. Some early scientific investigations developed the conceptual idea that this neutralisation could be achieved by placing a transparent substance, whether liquid or solid, in direct contact with the cornea.

There is a traditional claim that Leonardo da Vinci described and illustrated the theoretical principle of contact lenses in 1508. What Leonardo actually did was describe and illustrate a potential experiment in which a man immerses his face in a spherical glass bowl of water and is able to see his own shoulders. Retrospectively, this could be considered a description of a bioptic liquid lens in direct contact with the eye…but with the patient at risk of drowning!

It is further claimed that the scientist and philosopher Rene Descartes suggested the concept of corneal lenses. In his essay of 1637, La Dioptrique, Descartes described and illustrated an extending water-filled tube which would serve the purpose of lengthening the eye's axis. However, his text makes clear that the cover to this telescopic device was not a lens and that since there was no effective means of measuring the curvature of the cornea, it would be impractical to produce such a cover. The device, which appears never to have been made, would also have had to be held in place constantly, so that the open end kept its liquid contents in contact with the eye. No one had yet suggested a device to be worn underneath the eyelids.

In 1801 Thomas Young went so far as to fit a lens to a cornea although his aim was to demonstrate a scientific principle, not to assist the patient, who would have had to keep his face pointing towards the ground during the experiment. This lens had a brass rim and also featured a surrounding wax collar to retain fluid behind the lens, neutralising it and thus showing that the cornea was not involved in accommodation. Both a physician and a physicist, Young embodied the unique link between ophthalmologists and optometrists to be detected subsequently in this branch of optics.

In 1827, while studying astigmatism, John Herschel suggested using animal jelly as the neutralising substance. He even seems to have proposed a glass shell ground to a bespoke shape appropriate to the patient's eye. The main purpose of this glass however, was simply to retain the jelly in contact with the eye. No one knows if he actually tried this.

In 1887 Friedrich Anton Müller, an artificial eye maker, produced and fitted a blown glass contact shell as a protective cover for a patient's eye which had been ravaged by malignant disease. This was worn within the eyelids and it encased the cornea, but did not touch it. It had a white scleral portion overpainted with blood vessels, and the patient was still wearing it twenty one years later. Although rightly seen as a crucial development in the history of contact lenses, this device served a cosmetic function and was not a corrective lens. Only later was it discovered that if you ground away the central portion of the ‘shell’ you could give it the properties of a lens.

In 1888 Adolf Eugen Fick (in Zurich) and Eugene Kalt (in Paris) both independently fitted patients with optically corrective lenses, the latter using the cut-off ends of glass test tubes. A year later August Muller in Kiel went further in fitting a lens to himself, but the procedure wasn't easy. It required topical anaesthesia using cocaine, and he had to insert it with his head temporarily under water to prevent air bubbles. 

Early contact lenses in the 1890s were made by the practitioners fitting them, though sometimes in collaboration with optical manufacturers such as Carl Zeiss.  

Hard contact lenses made from ground glass were manufactured commercially by the early 1900s. As these covered the whole eye, including the white part, they are called scleral lenses. They required lubricating fluid to make them bearable and it was necessary to calculate the prescription of the surface of the lens to take into account the effect of the fluid that would lie behind it. By 1914 it was even possible, in some areas, to supply a contact lens from stock, although in London in the 1920s these still took six weeks to arrive from Germany.

By 1928 Adolf Müller-Welt of Stuttgart had applied for a patent for a fluidless lens, made from moulded glass. Rival products still required optical saline. Experiments with blown glass lenses were conducted in Japan. Meanwhile Josef Dallos, in Budapest, was concentrating on taking impressions direct from the patient's eye using dental materials. This enabled him to develop lenses that fitted the cornea closely but the sclera more loosely, which channelled natural tears to the cornea, so that in effect, patients were lubricating their own lenses.

The first British practitioner to make a contact lens was Kenneth Dunscombe in 1932. He had travelled to the Zeiss company in Germany to learn the technique.

In the USA Theodore Obrig developed plastics lenses made from acrylic resin in 1936. His compatriot William Feinbloom designed a lens in 1937 that combined a glass corneal portion with a plastic sclera. Plastics simply weren't clear enough to see through at this stage, but were materials for which it was easier to control the production process. They would ultimately win out because safer for patients to wear, with less risk of infection or breakage. 'Perspex' was trialled for this reason, but was found to be poor at transmitting enough oxygen to the eye beneath.

In 1944 Norman Bier patented the fenestrated glass lens. Small holes allowed an air bubble to relieve the cornea, at least doubling the time the lens could be worn. One patient claimed to have been able to wear a contact lens for an entire day.

The first text book on contact lens fitting, entitled simply Contact Lenses, was written by Obrig in 1942. The first British text book An Introduction to the Prescribing and Fitting of Contact Lenses by Frank Dickinson, was published in 1946.

The first UK optometry practice to specialise exclusively in contact lenses was opened by Keith Clifford Hall at 139 Park Lane, London, in 1945. In January 1947 the British Optical Association hosted the first meeting of a national specialist group for contact lens practitioners, The Contact Lens Society (CLS). By 1952 members had enough colleagues globally to join an International Society of Contact Lens Specialists (ISCLS). 

The world's first corneal lens was designed by accident in 1947, when the scleral portion of a haptic lens broke off. Kevin Tuohy patented the design in 1950. They were manufactured from PMMA and measured 11.5mm in diameter. Woehlk patented his own design at almost the same time, and the dimensions of that were closer to what corneal lenses on the market ultimately became.

In the 1970s cellulose acetate butyrate (CAB) was first used to make rigid gas permeable (RGP) lenses. The Menicon O2 lens from Japan was launched here in 1979. Some practitioners thought that this would usher in a new ‘Oxygen Era’ as such lenses caused less corneal trauma than the soft lenses available at that time, but they would mostly remain a type of lens for specialist cases.

Otto Wichterle, a material chemist working in Prague, developed the first hydrogel lenses, patenting the manufacturing process in 1959. Soft contact lenses came in during the 1960s though they did not suit every wearer. Indeed, in the very early days there were significant problems. Many of the early developments took place in Soviet-occupied Eastern Europe and new ideas were not necessarily transmitted quickly or accepted readily. Nevertheless, soft lenses were available to patients in the UK after 1962, and were even made here (briefly) by G. Nissel & Co., over a decade before the market-leading ‘Soflens’ was launched by Bausch & Lomb in 1973.

By the early 1970s the contact lens industry was in a state of transition. No longer confined to small producers, there was an element of 'big business' creeping in, with suppliers hoping to tap vast markets. Their primary commercial target was an increasingly affluent young generation, whom it was hoped would not only buy contact lenses for occasional use but for what was termed 'extended wear'. The Permalens, invented by the British optometrist John de Carle and commercially produced from 1974, was one of the first two soft lenses to be designed specifically for extended wear. It was still recommended that a patient remove them occasionally, for example at weekends. The same year Titmus Eurocon introduced cosmetic soft lenses with a printed or hand-painted iris.

In 1982 the world’s first disposable contact lens was introduced from Denmark, the MIA ('Danalens') lens. The eastern European pioneers of soft lenses were not far behind and quickly produced their own disposable version. Daily disposable lenses, for use just once before throwing away, were made available in 1995. The first was the Premier Award lens invented by Ron Hamilton in Scotland. The advantages of disposable lenses were better hygiene and the lack of time for the build-up of protein deposits. Due to concerns for the environment, some makers preferred to call them ‘daily replacement lenses’. Cosmetic coloured lenses, for social as opposed to medical use, emerged around 1988. In 1998 multifocal disposable soft lenses were made available by Bausch & Lomb. Silicone hydrogel lenses came onto the market in 1999.

Today, soft lenses remain the most popular type of contact lens due to their effectiveness at correcting most refractive eye conditions. There are even special soft lenses to correct problems caused by unsuccessful laser eye surgery. Manufacturers continue to vie with each other to claim greater levels of comfort, stability and lightness of weight.