Trends in CL prescribing

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How can events thousands of miles away across the Atlantic affect everyday life here in the UK? In a professional context, it might seem that there is little to be learnt from modes of practice in the US. Yet the annual report on the contact lens market by Contact Lens Spectrum1 makes interesting reading.

Published each year in January, the report not only looks at the distribution of lenses and care products dispensed in the US in 2008 but also gives leading brands and their market shares, information less readily available for the UK.

Differences between the two countries are more revealing than the similarities. Silicone hydrogels (SiHs) now dominate in the US, taking 54 per cent of lens fits and refits, with 35 per cent hydrogels and 10 per cent RGPs. The proportion of SiHs fitted in 2008 was similar to the 2007 figure but is expected to reach 75 per cent in the next two years for spherical lenses. Nearly one in three toric soft lenses fitted in the US is a SiH.

CL Spectrum editor Dr Jason Nichols observes that SiH use is much lower in other countries than in the US. His estimate for the uptake worldwide is 20 per cent for spherical lenses. UK data collected this time last year for new soft lens fits showed an equal split of 32 per cent for SiHs, mid-water hydrogels and high-water hydrogels.2

Replacement frequencies reveal even greater differences. Daily disposables make up only 10-13 per cent of lens fits in the US, compared to 35 per cent worldwide, and projected growth to possibly 20 per cent over the next two years. Two-weekly replacement is the preferred option with 44 per cent of the market. In the UK, daily disposables overtook monthly lenses for the first time last year, with 46 per cent of new fits. The popularity of this modality made the UK the natural test market for the first SiH daily disposable, which is yet to be launched in the US but has been available here since last year.

Among other prescribing trends were figures for prescription pharmaceuticals, of interest to therapeutically trained UK optometrists. Most respondents in Spectrum's survey reported writing between 10-15 prescriptions in a typical week. For anterior segment conditions, most prescriptions were for dry eye (average of 15 per week), followed by anti-allergy (11 per week), antibiotics (10 per week) and anti-inflammatories (nine per week).

The report also has a useful summary of some of the clinical research published in 2008 in contact lenses and the ocular surface, which is worth a look. Also included is a summary of new products introduced in the past 12 months. The full text can be accessed online via www.clspectrum.com, where references are available. Watch out for new international prescribing data coming up in a future issue too.

Efron and Morgan have been collating and publishing prescribing data on the UK market for well over a decade, including annual trend reports in Optician each year since 1996. More recently, long-term trends have been analysed by product sector in a series of short papers in the BCLA journal, Contact Lens & Anterior Eye, Optician's sister publication.

The latest paper reviews the prescribing of soft lens care regimens and charts the rise of multipurpose solutions, from 56 per cent of all systems in 1997 to 93 per cent in 2007. This increase was largely at the expense of one and two-step peroxide systems, which dropped from 20 per cent and 16 per cent of the market respectively, to 7 per cent and 0 per cent between 2001 and 2006.

No surprises there then, but more interesting is an apparent reversal of these trends in 2008, with MPS dropping back to 62 per cent, and one-step peroxide and 'other systems' increasing to 16 per cent and 2 per cent respectively. The authors suggest that the withdrawal of some MPS because of associations with Fusarium and Acanthamoeba keratitis, and concerns about corneal staining with certain MPS/lens combinations are among the likely causes. It will be interesting to see whether this trend continues in 2009.

So what, if anything, can practitioners learn from examining prescribing data? If nothing else, these trends may serve as a 'reality check' for changes in prescribing habits in everyday practice. They also offer an opportunity for those who record their own prescribing data to benchmark their habits against their peers, whether on an individual or practice basis.

Sometimes a report in the literature can give you pause for thought before you reach for the next lens or solution. A study from UK consultancy Visioncare Research published in the January issue of Eye & Contact Lenses is a case in point.4 Young and co-workers looked at marketing data for powers of soft lenses supplied during a one-year period in various countries/regions.

They found the power distribution curve for sphere powers spiked in 0.50D steps, illustrating a bias toward prescribing full and half-dioptre powers, with variations according to lens type. There were also variations between countries, presumably due to differences in training, fitting practices and supply routes. The authors conclude that there is widespread room for improvement in the prescribing accuracy of soft lenses. ?

References

1. Nichols JJ. Contact Lenses 2008. CL Spectrum, 200924:1 24-32.
2. Morgan P. Trends in UK contact lens prescribing 2008. Optician, 2008235:6155 18-19.
3. Efron N and Morgan PB. Soft contact lens care regimes in the UK. Contact Lens & Ant Eye, 2008 31:6 283-4.
4. Young G, Moody K and Sulley A. Anomalies in the prescribing of soft contact lens power. Eye & Contact Lens, 200935:1 11-14.