Soft contact lenses
How the Czechs went soft on us...
How the Czechs went soft on us...
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. Some of the early developments took place in Soviet-occupied Eastern Europe and new ideas were not necessarily transmitted quickly or accepted readily.
Otto Wichterle (1913-1998) a material chemist, claimed his inspiration to develop hydrogel materials came during a train journey in 1952 when he saw a fellow passenger reading an advert in an ophthalmological journal for a (metal) prosthetic eye. He had in mind a material for various medical uses including prosthetic implants. By 1955 he was already predicting that this theoretical new material could also be applied for use in soft contact lenses because it had the prospect of being both biocompatible and transparent. The challenge would lie in manufacturing precise shapes and ensuring that the edges were non-irritating, but the advantages were obvious: hydrogels would retain their strength and flexibility and not irritate surrounding human tissues. Furthermore, when dry they are hard and can be made as a block and lathed, for subsequent hydration.
Wichterle was becoming known across the world, a factor that perhaps simultaenously served to protect him and yet also raise suspicion from the Communist authorities. Already, by the late 1950s, he hosted an International Symposium in the Czech capital (1957) and became known as the ‘Wizard of Prague’. In 1959 he became the founding head of the Institute of Macromolecular Chemistry (IMC), which was a subsection of the Czechoslovak Academy of Sciences (CSAS, itself founded in 1952). At the IMC he experimented with soft lenses, working together with Drahoslav Lim from 1960.
Wichterle patented his hydrogel manufacturing process in 1959. The following year he co-authored an article in Nature with Lim. In this article they predicted the invention of an intraocular version and the eventual use of hydrogel to replace the eye's vitreous humour.
In 1961 Wichterle produced the first wearable soft lens at the IMC. He filed a patent on a new spin casting process and built his first spin-casting machine over the Christmas holiday. This was built at home because he did not believe the CSAS was the proper place for applied research. He used a toy Merkur building kit, a bicycle dynamo and part of an oxygen breathing apparatus (a 2L pressure bottle) left behind by the Luftwaffe, which he filled with argon.
In 1963 he patented an alternative lathe-turning method, and later that same year developed a coloured lens.
The first country outside of Czechoslovakia to obtain a supply of these hydrophilic lenses was New Zealand, to which some examples were apparently smuggled out in 1964. In October of that year some samples and a set of instructions were also sent, legitimately, to the optometrist Harry Green in London. Keen to seek ways of developing mass production Wichterle granted a licence to National Patent Development Corporation (NPDC) of the USA in March 1965.
The world’s first soft lens conference was held in Prague in 1965. Many of the early problems with the material were sorted out.
The illustrations show examples of 'Geltakt' and 'Spofa', two very early hydrophilic contact lenses in fluid-filled tubes from Czechoslovakia. The glass tube had to be broken to access the lens, with consequent risk from broken shards. This also meant that only unused lenses have survived to the present day. Our museum's example is therefore quite rare. Dominic Ruscio at Bausch & Lomb was the first to develop a non-glass phial/serum bottle to serve the storage purpose. He used 'Pyrex', as found in kitchens across in the world, sealed with a stopper and a foil cap.
British practitioners could obtain Czechoslovakian gel-lenses in the mid-late 1960s via the Merkuria Foreign Trade Corporation.
In 1967 F. A. Burnett-Hodd FBOA told the Contact Lens Society that there were an estimated 5.7 million lens wearers in the UK (nearly 10% of the population).
Rival product began to emerge at the very end of the 1960s. The ‘Bionite’ soft lens, developed by Allen Isen, was made available in 1969.
The Frank Dickinson Collection includes a 'Bionite NATURALENS' case in the form of a transparent plastic cylinder with a tight plastic pull-off lid and a removable white plastic base. This was designed for upright storage of the lens overnight and the minimum amount of storage fluid required was marked by a blue line. Note the instructions emphasising the importance of rinsing the case and replacing the solution daily. Unfamiliar to most UK contact lens opticians who have seen it, it is possible that Dickinson picked it up on his travels abroad and that this type of case was never made available in England.
Still working on soft lens manufacturing techniques, Otto WIchterle filed a patent for a vertical-column moulding technique in 1970.
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'. Contact lenses were available for all sorts of complicated conditions, but they were generally no longer required for correcting aphakia due to the availability of surgically implanted intra-ocular lenses (IOLs). It was envisaged that in future the majority of contact lenses would be prescribed for relatively low myopia corrections.
The salesmen and the practitioners did not necessarily share the same vision just yet, however:
The Association of Contact Lens Practitioners held a major soft lenses symposium in 1972. Our museum archive contains a handout from that conference. It is from a lecture concerning the Hydrolite Soft Plastic material. All the cases mentioned had previously been failures when conventional (i.e. hard) contact lenses were prescribed. The conclusion of the speaker, Robert Turner, was that hydrophilic lenses now constituted a 'second line of defence', but for use only when conventional lenses have failed.
HEMA - 2-hydroxyethyl metacrylate - a transparent hydrophilic plastic lens material. Wichterle's original material polyHEMA PHEMA was 40% water. Modern hydrogels can be up to 90% water.
Hydrophilic - a quality of a soft lens which transmits a certain amount of oxygen and may have varying water content. Lenses with a very high water content are for extended wear ('EW').
Soft contact lenses can be:
Lathe-cutting, also known as lathe-turning, can be used for mass manufacture, but is perhaps more normally employed for short production runs. It uses Xerogel (blocks of dry solid gel).
Spin-casting is a lot cheaper and can be done on a carousel (small-scale production) or a column-type machine (large-scale production). Wet gel is dripped into the mould. Only the outer curve of the lens is moulded; the inner curve (which is not spherical) varies depending upon the speed of spin and to an extent also on the quantity of monomers introduced, so the same mould can be used to produce lenses of different powers.
Soft lenses can also be cast-moulded (in which both surfaces are moulded) but WIchterle didn’t invent that process. Nevertheless, it has gone on to become the most common method of making disposable lenses.
In 1970 John de Carle and Galley started work on the ‘Permalens’, the first extended wear lens.
These are second generation Permalens lenses, still being produced at the time by the original maker, Global Vision. The blue labels denote negative power lenses and there were red labels for positive lenses. Later on 'Permalens' lenses were produced in their turn by Barnes-Hind / Cooper / CIBA. The changes in ownership of certain brand names can be one of the most complicated parts of tracing their history.The Soflens by Bausch & Lomb was the first soft contact lens to be FDA-approved for supply in the United States, in 1971 and was supplied from 1972. (Beware: Many American websites state this as the year soft lenses were first introduced; they mean only with regard to their own country. We, and other countries, had them sooner!) The development did, however enable a global market to open up.
In 1974 Titmus Eurocon introduced the first cosmetic soft contact lens with either a printed or a hand-painted iris. The same year their Weicon Soft Toric lens introduced the concept of dynamic stabilisation.
The Czechs endured extended disputes concerning the foreign manufacturing licences during 1975. In May 1977
the CSAS sold all Wichterle’s patents and cancelled all licences. 1981 saw the start of a second round of licence contracts for spin-casting machines. Disputes over these were settled by 1982.
To the left is the original Hydrocurve design of soft lens. Notably the label says that they were for 'extended wear'. The Hydrocurve bifocal introduced by Barnes-Hind in 1977 was the first aspheric soft bifocal lens.
Toric contact lenses were made available in 1978.
The Duragell (right) was a type of 1970s lens with extended wear capability.
To the far right is the second generation Hydron lens (the originals had metal caps). The screw-lid jar is a typical Smith & Nephew container and may be compared with, for example, their 'Snoflex' range.
In 1978 Syntex produced the first non-HEMA material soft lens, known as the CSI.
Tinted daily wear soft lenses were made available in 1980.
Extended wear soft lenses were made available in 1981. There were dangerous problems which would arise with these such as a risk of ulcerative corneal complications from improperly sterilised lenses, though these problems went largely unnoticed at first until large-scale clinical studies revealed the worrying pattern.
Bifocal daily wear soft lenses made available in 1982.
The Aoflex soft lens was developed by Pierre Rocher in France. Rocher spent many years in the contact lens industry manufacturing PMMA, soft and RGP lenses until 1984, when he chose to develop an optometry practice mainly devoted to presbyopic patients fitted with progressive ophthalmic lenses.
Also, in 1984, Otto Wichterle (still going strong) finally developed the intraocular hydrogel lens he had predicted a quarter of a century before.
Cosmetic coloured lenses were made available in 1988.
1993 was ther final fling of the Czechs. That year withnessed a third licensing contract concerning the technology and equipment for spincasting. Partners in South Korea were supplied with a combination carousel.
Hydron T lenses
This is a contact lens fitting set from the early 1990s consisting of 7 polymacon B hydrophilic soft toric lenses (43% water) in sealed fluid-filled jars arranged in a grey foam rack, removable from its white plastic 'video tape'-type case. This product represents a brief liaison between a solutions company (Allergan) and a lens manufacturer (Hydron) to produce a moulded soft toric lens. Polymacon was an improvement upon HEMA.
This pack of 'Choice A.B.' soft lenses (pictured left) contains a customer information card to the effect that the box contains easier to open blister packs, introduced by customer demand. In fact blister packs were a natural progression, saving considerable weight as disposability led to a significant increase in the numbers of lenses supplied in one go. 'Choice' was a hydrophilic disposable soft lens (45% methafilcon) with a light blue tint. Like many of the samples in the BOA Museum, this is a diagnostic pack, designed to help the practitioner fit the correct lens before dispensing them to the patient.
New generation extended wear soft lenses were introduced in 1999.
'Soflens 66' was a popular spherical prescription lens, manufactured by Bausch & Lomb in Waterford, Ireland. This set of three sterile blister packs dates from circa 2000. This monthly disposable lens was still available, though differently packaged, at the time of writing (2008).
Extreme H20 Lenses came from America (c.2000) and were promoted as 'The contact lens that will not dry on the eye'. Note their presence within a retail display box which would originally have contained 12 lenses. The museum also collects this in-practice promotional material.
Today soft lenses remain the normal type of contact lens that optometrists will prescribe. Pretty well most refractive conditions can be corrected with soft contact lenses. There are even special soft lenses to correct problems caused by unsuccessful laser eye surgery. Manufacturers vie with each other to claim greater levels of comfort, stability and lightness of weight.
Marco Stella, Jiri Michalek, Ivana Lorencova and Antonin Kostlan, Otto Wichterle, Scientist and Inventor (Prague: Czech Centres, 2013) - This is the catalogue for the exhibition Otto Wichterle – The Story of the Contact Lens, marking the centenary of his birth.
The BOA Museum Guide to a modern soft contact lens
Here is a brand new soft toric contact lens in its sterile saline-filled blister pack. This pack is a relatively plain shape; others come with rounded edges or even in the shape of tear-drops. Note the list of ingredients including the water content of the lens material (57%), the European CE mark of approval, the dimensions (dia = diameter, BC = back curve) in millimetres and the optical power in dioptres (-2.50 D with a small amount of cylindrical power too to combat astigmatism). 'Rx only' means that the lens is only to be supplied on prescription. There is also a written warning that the lens is for single patient use and should not be shared because of the risk of cross-infection. See another webpage in this section to learn more on contact lens hygiene.
The Lot Number is clearly marked in case of a product recall and the Expiry Date is plainly stated in the form of a month and a year. This particular lens has a blue tint. The tint is not cosmetic in any way, for example to alter the colour of the patient's eyes, but to assist with handling. This can be a particular boon if the lens is dropped.