In his report of the 11th annual Eurolens Research survey into prescribing habits, Dr Philip Morgan looks at the surge in silicone hydrogel fitting for daily wear
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The 11th annual survey into UK contact lens prescribing was conducted between January and March 2006.1-10 The same format as previous years was employed. One thousand practitioners (700 optometrists and 300 dispensing opticians who fit contact lenses) were selected at random from the GOC register.
A questionnaire with reply-paid envelope was sent to this group who were asked to provide details of the first 10 patients fitted with contact lenses after receipt of the questionnaire. The questionnaire was specifically designed to be straightforward to complete while capturing the key information about the patients.
Practitioners were asked some questions about themselves, and for each contact lens fit, they were requested to complete the details about the following: date of fitting, new fit or refit, age and sex of patient, lens material, lens design, frequency of replacement, times per week of wear, modality (daily or extended wear) and care system.
Completed questionnaires were received from 119 practitioners (45 dispensing opticians, 72 optometrists and two ‘not recorded’) providing information on 1,088 contact lens fits. Each fit was given a weighting based on the number of lenses fitted per year by the practitioner (based on the date information on the form). This means that fits by practitioners conducting many contact lens fits were afforded a higher weighting than those performing fewer fits. The mean (±SD) age for the contact lens fits reported was 36.7 ± 14.7 years with an age range of nine to 84 years.
This average age is slightly higher than previous years. In common with previous years, two in three contact lens fits (63 per cent) were to females.
Rigid versus soft lens fits
Soft lenses accounted for 95 per cent of all new fits and 83 per cent of refits (Figure 1). This value for new fits has remained constant for about seven years. The popularity of rigid lenses for refits has recovered to 17 per cent from 12 per cent in 2005, but this is still lower than the values generally seen over the past 10 years.
Soft lens details
Perhaps the most significant data this year details the use of silicone hydrogel materials for daily wear. These materials now account for 30 per cent of soft new fits and 45 per cent of soft refits, respectively. In fact, if only spherical, daily wear, non-daily disposable fits are analysed, 69 per cent of lenses prescribed were silicone hydrogels. This is a remarkable development only two years since the launch of silicone hydrogels specifically marketed for daily wear.
Figure 2 shows the use of silicone hydrogels for extended wear and daily wear as a proportion of all contact lens fits. This confirms the rapid rise of these lenses for daily wear while their use for extended wear has remained relatively constant since 2002.
Monovision corrections are now more popular than multifocals for soft lens fits, a reversal of recent trends. Analysis suggests that this factor may also be related to the increase of silicone hydrogel lenses as more than half of monovision fits were with this material. By contrast, silicone hydrogel multifocal lenses are only just becoming available, and it seems that until these are more commonplace, practitioners are preferring to opt for silicone hydrogel monovision than for hydrogel multifocals. Overall, the proportion of multifocal lenses has remained similar to previous years while monovision fits have increased significantly.
The replacement frequencies of prescribed soft lenses shows 33 per cent of new fits with daily disposables and 49 per cent with monthly lenses. This year, there has been a significant change in the proportion of 1-2 weekly replaced lenses, up to 17 percent of new fits in 2006 from 3 per cent in 2005, thereby breaking the total dominance of daily and monthly replaced lenses.
Figure 3 shows the distribution of care systems for soft lenses. While multipurpose solutions remain the most commonly prescribed (81 per cent), the proportion of one-step peroxide solutions has increased from 8 per cent of care systems in 2005 to 18 per cent in 2006. Two-step peroxide systems are now very rarely prescribed.
Rigid lens details
Mid-Dk (40 to 90Dk units) materials were the most commonly prescribed, accounting for 46 per cent of new fits and 80 per cent of refits. Orthokeratology fits accounted for one third of new rigid fits (and about 1 per cent of all fits for 2006).
Commentary
It appears that 2006 can be labelled as the ‘Year of the Silicone Hydrogel Lens’ as these relatively new entrants to the daily wear market now represent the majority of fits for spherical (non daily-disposable) lenses. This suggests that practitioners in the UK are convinced of the clinical benefits of this lens type and their use is set to increase with the recent launch of toric and multifocal silicone hydrogels, and with more manufacturers offering silicone hydrogel lenses.
Acknowledgements
This survey was funded by the sponsors of Eurolens Research: Bausch & Lomb Incorporated, Advanced Medical Optics (UK), Alcon Laboratories (UK), CIBA Vision (UK), CooperVision, Johnson & Johnson Vision Care, Menicon Co, Sauflon Pharmaceuticals and Clearlab UK. The author would like to thank the contact lens practitioners who anonymously participated in this survey.
References
1 Morgan PB, Efron N. Trends in UK contact lens prescribing 2005. Optician, 2005; 229(6004): 28-29.
2 Morgan PB and Efron N. Trends in UK contact lens prescribing 2004. Optician, 2004; 227(5950): 16-17.
3 Morgan PB, Efron N. Trends in UK contact lens prescribing 2003. Optician, 2003; 225 (5904): 34-35.
4 Morgan PB, Efron N. Trends in UK contact lens prescribing 2002. Optician, 2002; 223 (5849): 28-30.
5 Morgan PB and Efron N. Trends in UK contact lens prescribing 2001. Optician, 2001; 221 (5803): 38-39.
6 Morgan PB and Efron N. Trends in UK contact lens prescribing 2000. Optician, 2000; 219 (5749): 22-23.
7 Morgan PB and Efron N. Trends in UK contact lens prescribing 1999. Optician, 1999; 217 (5700): 43-44.
8 Morgan PB and Efron N. Trends in UK contact lens prescribing 1998 Optician, 1998; 216 (5679): 18-19.
9 Morgan PB and Efron N. Trends in UK contact lens prescribing 1997. Optician, 1997; 214 (5630): 32-33.
10 Morgan PB, Ramsdale C and Efron N. Trends in UK contact lens prescribing 1996. Optician, 1997; 213 (5583): 35-36.
Dr Philip Morgan is the director of Eurolens Research at the University of Manchester. A review of the Eurolens Research surveys 1996-2005 is presented in the current issue of Contact Lens and Anterior Eye.