From
Bottles to Blisters - a history of disposable lenses in the UK
(From
Optician 30 May 2008)
In the last 20 years there have arguably been more
developments in the field of contact lenses than in the whole of the preceding
century. In 1988, almost exactly 100 years after the first scleral contact lens
was recorded in the late 1880s, the first disposable lens was introduced into
the UK.
A look back at the history of
contact lenses shows that a number of key events followed the introduction of
the original glass shells: the application of PMMA in 1937 the corneal lens in
1947 the soft lens by Wichterle in 1961 the fully-fledged, mass-produced,
disposable lens by Johnson & Johnson Vision Care in 1988 and the first
silicone hydrogels in 1999. Of these events, the arrival of disposable lenses
has almost certainly had the greatest effect on practitioners, the public and
contact lens manufacturing.
With remarkable prescience, the
concept of disposability was predicted by Wichterle himself during the 1960s1
and in a 1980s interview when, speaking of lens deposits, he said: 'Discard the
coated lenses and replace them with new ones. What we need is an inexpensive,
absolutely reproducible lens so the [replacement lens] will not require another
fitting.'2
The original concept of
disposability, developed by Johnson & Johnson and endorsed by the Food and
Drug Administration (FDA) in the US, was that no lens should ever be reused. It
should either be for single use and thrown away daily or worn for a prescribed
period of extended wear and similarly discarded on removal. This, of course,
only became possible in 1988 with the arrival in the UK of the original Acuvue
lens (Figure 1), which introduced several ideas new to contact lens practice.
Practitioners had to familiarise
themselves with single-use blister packs instead of glass vials which required
crimp sealing and autoclaving. There were now diagnostic lenses to replace
reusable trial lenses - if a lens was unsuitable on the eye, it was immediately
discarded. Practitioners were initially required to purchase a comprehensive
fitting stock from which to dispense lenses immediately to patients and suddenly
they had to come to terms with stock control and a system of packaging to
accommodate three or six months' supply of lenses. Johnson & Johnson also
led the way in encouraging the use of standing orders and direct debits.
The introduction of the Acuvue
lens more or less reinvented extended wear, which had fallen out of favour.
There was a two-tier pricing structure to correlate with weekly use for extended
wear and fortnightly replacement for daily wear. There was also comprehensive
support from a UK professional services team with advice on fitting and any
clinical problems. In fact Johnson & Johnson has always employed key
professional personnel to assist practitioners, maintain their ongoing
educational programmes, and promote research and development. This culminated in
2006 with the opening of its first Vision Care Institute in Europe.
New frontiers
The continuing success of Acuvue
lenses has been based in part on the ground-breaking material, etafilcon A, a
group IV polymer. This had originally been developed in Jacksonville, Florida,
by Seymour Marco of Frontier Contact Lenses, a relatively small US manufacturer.
The material had received FDA approval in the US during 1978 and the company was
bought by Johnson & Johnson in 1981, subsequently to be renamed Vistakon. In
1984 it acquired the rights to the 'stabilised soft moulding' process developed
by Michael Bay of Copenhagen for the rudimentary disposable Danalens. That,
however, is where the similarity ended. The expertise of a major pharmaceutical
company prepared to make the large financial investment necessary brought
disposable lenses to the next stage. Vistakon spent several years developing the
final product, employed the more stable and reproducible etafilcon A material,
refined the previously labour-intensive manufacturing process and originated
truly airtight and sterile packaging in the form of the now-ubiquitous blister
packs. The disposable lens as we know it today had arrived.
The contact lens world was
already becoming accustomed to the notion of frequent replacement on a
three-monthly basis,3 for example with the Freshlens system from
Bausch & Lomb. But it fell to Johnson & Johnson to set the scene for the
explosion in disposable lenses to come. These included monthly lenses such as
SeeQuence by Bausch & Lomb, soon to be followed by Precision UV from
Pilkington and Surevue by Johnson & Johnson as a less expensive alternative
to Acuvue with easier handling properties (Figure 2). The disposable route has
subsequently been followed by all major contact lens manufacturers to the almost
complete exclusion of conventional lenses.
Most practitioners, however, not
overly enthusiastic about extended wear, subverted the single-use concept and
changed daily-wear frequent replacement - three monthly - into daily-wear 'very
frequent replacement' - fortnightly or monthly. Disposable lenses became the
accepted term for lenses replaced at intervals of one month or less.
The many advantages of
disposability were soon recognised. There were, understandably, some potential
disadvantages, many of which have since been overcome. Table 1 summarises the
advantages and disadvantages of the original disposable lenses, along with the
additional advantages 20 years on and how the potential drawbacks with these
lenses have changed during that time.
Over the years, there have been
significant developments since the first disposable lens was introduced. In 1997
Johnson & Johnson responded to concerns about ocular damage from ultraviolet
(UV) radiation4 and, although not the first to do so, began to
include such protection as a standard feature in all subsequent lenses. The
following year, it relaunched the original lens as the Acuvue 2 with a new edge
design, easier handling and improved comfort. Johnson & Johnson also
acknowledged environmental issues and by this time the original plastics
containers had been replaced by much smaller and recyclable cardboard boxes. The
Acuvue 2 range was later supplemented by Acuvue 2 Colours opaque and enhancer
lenses.
Specialist lenses
By the late 1990s disposables had
frequently become the lenses of first choice.5 Practitioners were impatient for
specialist lenses such as bifocals and torics on which various laboratories were
known to be working. 1995 saw the introduction of the first monthly disposable
lenses for astigmatism, Focus Toric by CIBA Vision and FreshLook Toric by
Wesley-Jessen, the former company absorbing the latter in 2000. The new century
saw Johnson & Johnson bring its own toric to the market. The company
followed its established policy of developing a new lens for the purpose rather
than adapting an existing design. In this case dual thin zones were employed to
give both good comfort and stability.
In 1996, Bausch & Lomb
introduced a monthly disposable multifocal in the form of the Occasions lens,
based on its earlier conventional PA1 design. Johnson & Johnson launched
during 1998 its Acuvue Bifocal, an innovative design described as 'pupil
intelligent' - a four-zone bifocal with a full range of reading additions. Once
again there was a complete system of storage, display and practitioner support.
These were followed by other multifocals, such as Rythmic 1 from Essilor,
Progressives from CIBA Vision and Frequency from CooperVision.
Daily disposables
Having been shown the advantages
of disposability, practitioners were eager for the next major development, daily
disposable lenses. By 1995, these had duly appeared in the UK.
With 1-Day Acuvue (Figure 3),
Johnson & Johnson was able to return to the original concept of
disposability that no lens should be reused. Once again the company waited until
it had evolved a complete system for the practitioner, utilising the proven
etafilcon A material, a comprehensive range of powers and newly designed lens
storage and packaging. It was followed in early 1996 by Bausch & Lomb, which
had acquired the Award lens manufactured in Scotland, and by CIBA Vision with
its Focus Dailies in 1997.
Daily disposables have provided
almost as much of a revolution in contact lens practice as disposables in
general. They are the ideal lenses for patients who want an irregular wearing
schedule for sports or social events. They eliminate altogether the need for
cleaning and solutions - ideal for the atopic and indolent patient alike.
Emergency visits are less common and they are also an excellent way to
rehabilitate patients following contact lens-associated papillary
conjunctivitis, infection or other interruption to their wearing schedule. These
advantages had immediate appeal to both the UK profession and public and by 2007
daily disposables accounted for 40 per cent of new contact lens fittings in the
UK,6 a higher proportion than in the US, the home of disposability.
Since 2001, new designs have
emerged including the first multifocal and toric daily disposables, Focus
Dailies Progressives and Focus Dailies Toric, and the first daily disposable
coloured lens, 1-Day Acuvue Colours. More recently, a second generation of daily
disposables has been introduced in which various additives are incorporated
within the lens or packaging solution to enhance wearer comfort. Launched in the
UK in 2006, 1-Day Acuvue Moist with Lacreon Technology was a recent addition to
the Acuvue daily disposable range.
Silicone hydrogels
The next major contact lens
development occurred in 1999 with the launch of silicone hydrogels for extended
wear,7 by Bausch & Lomb (PureVision) and CIBA Vision (Focus Night
& Day). Disposables had in a way come full circle. The original Acuvue was
thought to be a safer route for extended wear than conventional, non-disposable
lenses due to their more frequent replacement and fewer nights of consecutive
wear. While extended wear with disposable lenses reduced many inflammatory
events associated with overnight wear, disappointingly it did not result in a
major reduction in the incidence of microbial keratitis. Silicone hydrogels
offer significantly greater oxygen supply to the cornea compared to hydrogel
materials, easily fulfilling the Holden-Mertz oxygen criterion for closed-eye
conditions.8 It was therefore considered that the lenses launched in
1999 would be safer for extended wear. With the benefit of hindsight, we now
know that with overnight wear the incidence of corneal infection with silicone
hydrogel lenses is similar to that for traditional hydrogels but the severity is
less.9
Disposable lenses had returned to
the original concept of single use. They now offered what might be termed the
two poles of convenience: daily disposables with nothing for the patient to do
but insert, remove and discard or extended wear in which lenses were inserted
with no action required by the patient until replacement up to 30 days later.
Silicone hydrogel was the first material to be introduced solely in disposable
form - the opposite of hydrogel lens development - and it is ironic that in the
past year or so, non-disposable lenses such as CIBA Vision's custom-made lens,
Air Optix Individual, have appeared in this material.
Silicone hydrogels were
immediately welcomed by practitioners for their excellent physiological
properties but, partly because of the higher price and recommendation for 30
nights' extended wear, their uptake began fairly slowly and had only achieved 1
per cent of new fittings by 2001.10 Not all practitioners were
comfortable with extended wear and indeed many were very soon requesting lenses
in the new material for purely daily use without the premium attached for
overnight wear.
Johnson & Johnson was able to
satisfy this demand with the launch in the UK during 2004 of Acuvue Advance with
Hydraclear. This was the first of what has been described as the second
generation of silicone hydrogels. The key difference was a much lower modulus of
elasticity. This created a more flexible material (galyfilcon A) which, for many
patients, gave better initial comfort and a lower incidence of arcuate staining.
In addition, the galyfilcon A material includes within the polymer a wetting
agent (PVP) which helps make the lens wettable throughout. The galyfilcon A
material also eliminates the need for surface treatment and produces a lens with
better wettability and improved comfort at the end of the day. Acuvue Advance
was immediately available with two fittings and a full range of powers. Its
ready acceptance allowed Johnson & Johnson to use it as the basis for the
toric version, Acuvue Advance for Astigmatism, introduced the following year.
This employed the new Accelerated Stabilisation Design, which has subsequently
been used in its daily disposable hydrogel toric.
In 2005, Acuvue Advance was
complemented by Acuvue Oasys (senofilcon A) using related technology called
Hydraclear Plus. The improved Dk and wettability of these and other silicone
hydrogels, such as Air Optix (CIBA Vision), meant that lenses began to be used
for either daily or weekly extended wear. With these advances, prescribing of
silicone hydrogels for new patients had risen to 15 per cent of new fits by
2005.11 There have since been several other second-generation
silicone hydrogels including Biofinity (CooperVision), Premio (Menicon) and a
new version of the original PureVision (Bausch & Lomb) which is reported to
have a reduced modulus.
More than a million
Since the introduction of the
first disposable lenses some 20 years ago, new contact lens designs and
materials have appeared with almost exponential regularity. In the UK, soft
lenses represented 97 per cent of new fits in 2007, with disposables accounting
for 98 per cent of these.6 Silicone hydrogels, originally slow
starters, accounted for a rapidly increasing 28 per cent of new fittings in 2007
and for more than half of all soft lens refits (52 per cent).6 With
daily disposables, we can safely say that well over a million new lenses are now
opened and used every day in the UK.
Contact lens practitioners and
manufacturers have embraced disposable lenses for clinical, financial and
logistical reasons. In addition, some patients now decline professional advice
to have conventionally replaced soft or gas permeable lenses, even when these
lenses may be more appropriate, because of the lure of disposability.
Another concern is the universal
availability of lenses from non-professional sources - mail order and the
internet - which reduces an essential element of practitioner control. Such
considerations have led many practitioners to change their professional fee
structure and charge more realistically for their time. Patients, on the other
hand, demand comfort and convenience, but at the same time have readily
assimilated the advantages in hygiene, oxygen performance and UV protection that
disposable lenses can provide.
Looking at the time line in Table
2 we can see that Johnson & Johnson has been at the forefront of disposable
lens innovation. It has not necessarily always been the first but has
consistently decided on a clinical objective, developed the material,
manufacturing process and lens for that specific purpose, and set this within a
complete system of practitioner support, supply and information.
Present and future
But what would we practitioners
ideally like now? The gradual introduction of custom-made silicone hydrogels by
various companies is a welcome step but we need a wider range of powers in all
disposable lenses, up to perhaps ±20D. This would accommodate the high
prescriptions that used to be available in the conventional lenses which have
steadily been discontinued. Johnson & Johnson currently offers a wide range
from -12.00D to +8.00D but an extension by all manufacturers would solve many
clinical problems.
Next, we would like the greater
availability of specialist lenses such as multifocals and torics in daily
disposable form. Finally, the current philosopher's stone of contact lens
practice is a silicone hydrogel daily disposable that would combine the best
physiological characteristics with the ultimate in disposability. Twenty years
after the first disposables appeared in the UK, such a
lens has just been announced.
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Meyler J and Schnider C. The role of UV-blocking
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Morgan PB and Efron N. A decade of contact lens
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Morgan PB and Efron N. Trends in UK contact lens
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Sweeney DF. The rebirth of extended wear.
Optician 1999 218:5721 18-9.
Holden BA and Mertz GW. Critical oxygen levels to
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Vis Sci 198425: 1161-7.
Efron N, Morgan PB, Hill EA et al. Incidence and
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Morgan PB and Efron N. Trends in UK contact lens
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Morgan PB and Efron N. Trends in UK contact lens
prescribing 2005. Optician 2005229:6004 28-29.
● Optometrist Andrew Gasson
is in private practice in central London specialising solely in contact lenses.
He is a special subject adviser to the Contact Lens Collection of the British
Optical Association Museum