International Contact Lens Prescribing in 2003
This yearly snapshot reveals the diversity of lens prescribing practices around the world.
By Philip B. Morgan, PhD, MCOptom, FAAO, Nathan Efron, DSc, MCOptom, FAAO (DipCL), Craig A Woods, PhD, MCOptom, DipCLP, FAAO, Deborah Jones, BSc, FCOptom, DipCLP, FAAO, Ioannis G. Tranoudis, DO, MSc, PhD, Motozumi Itoi, MD, PhD, Eef van der Worp, BSc, FAAO, FIACLE, Magne Helland, BSc, MScOptom, FIACLE, Anna Yeo Chwee Hong, BOptom, (Hons) MAppSc, FIACLE, and Joseph T. Barr, OD, MS, FAAO
This is our third annual survey of international contact lens prescribing trends. Between January and March 2003, we analyzed prescribing habits in 10 countries: Australia, Belgium, Canada, Greece, Japan, the Netherlands, Norway, Singapore, the United Kingdom and the United States. In the larger countries, we randomly sent 1,000 surveys to contact lens practitioners selected from national registers of qualified clinicians (in the United States, we used the subscriber list of Contact Lens Spectrum). In Norway and Singapore, where the number of practitioners is less than 1,000, we mailed out a pro rata quantity of surveys.
The survey forms elicited prospective information about the types of contact lenses and care products that respondents prescribed to a maximum of 10 patients fit after the study commenced. We employed a system of weighting to better reflect the fitting practices of busier practitioners.
This year, we received data about 13,787 contact lens fits, with the greatest number in Japan (4,609) and the lowest in Greece (460) (Table 1). Women accounted for two-thirds of all fits, ranging from 60 percent in Norway to 70 percent in Japan. The mean age of lens patients was lowest in Singapore (26.5 years) and highest in the United States (34.1 years). In the Netherlands, practitioners fit only two percent of patients on a part-time wear schedule (three days or less of contact lens wear per week) compared to 22 percent in the United Kingdom.
It's possible to use the data presented here to indirectly measure the health of a country's contact lens market by evaluating the number of lenses prescribed for new fits (patients with no history of lens wear) compared with those prescribed to refits.
For example, in the United States new wearers represented one-third of lens fits, with existing wearers representing the other two-thirds. Compare this to 47 percent (maximum) new fits in the United Kingdom and 26 percent (minimum) in Singapore.
Figure 1. The proportion
rigid lenses prescribed in Australia (AU), Belgium (BE),
Canada (CA), Greece (GR), Japan (JP), the Netherlands
(NL), Norway (NO), Singapore (SG), the United Kingdom (UK)
and the United States (US).
Soft Lenses vs. Rigid Lenses
Rigid contact lenses accounted for 14 percent of all new fits and 21 percent of refits (Figure 1). This difference reflects the greater historical use of rigid lenses. For new fits, rigid lenses accounted for more than 20 percent of lenses prescribed in the Netherlands, Greece, Japan and the United States. As in previous years, Norway prescribed the lowest number of rigid lenses at only one percent of new fits.
Soft Lenses for Extended Wear
Soft lenses for extended wear accounted for more than 20 percent of refits in Australia, Norway and the United States (Figure 2 and Table 2). These percentages were lower for new fits, in which Australia and the United States fit the most new patients.
Generally, practitioners chose silicone hydrogels for soft lens extended wear, with this lens type accounting for more than 90 percent of extended wear fits in Australia, Norway and the United Kingdom. Greece and the United States reported the lowest use of silicone hydrogels for extended wear at 41 percent and 52 percent respectively, with the exception of Japan, where this lens type is not available. In the United States, 33 percent of soft extended wear lenses were mid-water content hydrogels.
|Figure 2. Soft lens patients prescribed extended wear.||Figure 3. Soft daily wear lens replacement schedules.|
Soft Lenses for Daily Wear
Mid-water (40 percent to 60 percent water) soft lens materials were the most popular for daily wear overall, prescribed for 63 percent of new fits. Low-water lenses were relatively popular in Japan, Singapore and the United States. European practitioners rarely prescribed low water lenses; these lenses represented only three percent of fits in the United Kingdom.
Prescribing silicone hydrogel lenses for daily wear was popular in a number of countries including Belgium and the Netherlands (65 percent and 48 percent, respectively).
Lens Designs Spherical lenses represented the most prescribed soft lenses for daily wear. Toric lenses ranked second, accounting for 29 percent of new soft daily wear fits in Australia and Singapore, but only nine percent of new fits in Japan. Multifocal/monovision correction was greatest in the United States (16 percent of new fits) and Canada (13 percent of new fits) compared to Japan and Singapore (one percent of new fits).
Daily Wear Modalities Daily disposable lenses accounted for 48 percent of new fits in Norway, 35 percent in the United Kingdom and 29 percent in Japan (Figure 3). These values typically numbered about 10 percent for all other countries examined.
For reusable daily wear lenses, respondents in all countries preferred a monthly replacement interval except in Japan, where practitioners prescribed 56 percent of lenses for one- to two-week replacement. This indicates that in Japan, 85 percent of soft daily wear patients replaced their lenses every two weeks or more frequently. No respondents from the Netherlands or the United States recorded using unplanned soft lens replacement, and for all other countries this number was 11 percent or less.
Respondents worldwide prescribed multipurpose care systems for 83 percent of patients (Figure 4). Hydrogen peroxide products held greater popularity in some countries, accounting for 34 percent of care systems in Belgium. Generally, respondents prescribed one-step peroxides more frequently than their two-step equivalents.
|Figure 4. Care systems prescribed to soft lens wearers.||Figure 5. Rigid lens patients prescribed extended wear.|
Rigid Lens Prescribing Trends
The most commonly prescribed rigid lens materials worldwide were mid-Dk (40 to 90 barrers), except in Japan (mostly high-Dk lenses) and Greece (mainly low-Dk lenses) (Table 3). Practitioners in some countries may rely on rigid lenses for more complex fits. For example, in Australia 46 percent of rigid lenses prescribed were toric. In the United Kingdom, 22 percent of rigid lenses were multifocals.
A number of countries have embraced rigid lens planned replacement. Respondents in Australia, Canada, Greece, Norway, the United Kingdom and the United States prescribed more than 25 percent of rigid lenses on a planned replacement basis.
This year's survey indicated that a number of countries prescribe rigid lenses for extended wear (Figure 5). Canadian practitioners prescribed almost 20 percent of rigid lenses for this modality, and Belgium, the Netherlands and the United Kingdom also reported significant numbers. This might reflect rigid lens use for overnight orthokeratology; we will specifically target this option in the 2004 surveys.
Clear differences exist in contact lens prescribing habits among the countries surveyed in 2003. Although soft lenses are the most commonly prescribed type overall, practitioners in Canada, Greece and the United States have fit an increased proportion of rigid lenses. Also, significant movement in the area of extended wear has occurred, with an increased proportion of extended wear patients in Australia, Canada, Norway and the United States.
This survey was funded by the sponsors of Eurolens Research: Bausch & Lomb Inc., Alcon Laboratories (UK) Ltd., Advanced Medical Optics (UK) Ltd., CIBA Vision (UK) Ltd., CooperVision Ltd., Johnson & Johnson Vision Care, Menicon Co. Ltd., Ocular Sciences Ltd. and Sauflon Pharmaceuticals Ltd. Additional funding in Greece provided by Johnson & Johnson and in Norway by the Norwegian Optometric Association.
Dr. Morgan is the research manager of Eurolens Research, UMIST, Manchester, UK.
Dr. Efron is a professor of Clinical Optometry and director of Eurolens Research, UMIST, Manchester, UK.
Dr. Woods is a senior research optometrist at Clinical Vision Research Australia, Victorian College of Optometry and Senior Fellow, Department of Optometry and Vision Sciences, University of Melbourne, Australia.
Dr. Jones is the clinic director and head of the Pediatric and Special Needs Clinic at the School of Optometry, University of Waterloo, Waterloo, Canada.
Dr. Tranoudis is director of the Centre for Contact Lens Research and Fitting and director of the Contact Lens Laboratory, Department of Optics, Technological Educational Institution, Athens, Greece.
Dr. Itoi is an associate professor, Department of Ophthalmology, Juntendo University, Tokyo, Japan.
Dr. van der Worp is head of the Contact Lens Department at the School of Optometry, Hogeschool van Utrecht, Utrecht, Netherlands.
Dr. Helland is an associate professor at the Department of Optometry and Visual Science at Buskerud University College, Kongsberg, Norway.
Dr. Yeo is a lecturer at Singapore Polytechnic, Singapore.
Dr. Barr is the editor of Contact Lens Spectrum and is Assistant Dean for Clinical Affairs at the Ohio State University College of Optometry.