With the increase in myopia throughout the world, especially in Asia, we are seeing a rapid rise in the use of contact lenses in the region.
It was interesting to see contact lens patient behaviour and trends in the region highlighted in presentations at the Asia Pacific Contact Lens Care Summit, held late in 2007 in Singapore.
How does microbial keratitis compare?
One question that has arisen is whether the increase in contact lens wear in the Asia Pacific region has brought about a rise in contact lens related infections. Reports of increased numbers of infection in countries in the region have been of some concern to local practitioners.
A number of recent studies have examined rates of contact lens complications,1,2 enabling comparisons between the rates of microbial keratitis (MK) with extended wear (EW) contact lenses in different regions (see Figure 1). This shows that while there may have been an increase in the absolute number of cases in Asia Pacific, the rates per population remain low, as in other countries.
…contact lens wearers seem to pay less attention to case hygiene than lens hygiene
Is hygiene an issue?
While the low MK rates are reassuring, presentations at the Summit showed that hygiene is just as much an issue in the Asia Pacific region as elsewhere.
One study3 investigating contact lens hygiene in a group of young, university-based, asymptomatic patients in Hong Kong, found that these patients had become complacent in their contact lens routines.
Over 100 soft contact lens wearers were interviewed and their lenses, solutions and storage cases tested for microbial contamination.
For these patients the lens case was the most frequently contaminated item – contact lens wearers seem to pay less attention to case hygiene than lens hygiene. In interviews, over half of the wearers (58 per cent) admitted they didn’t discard the lens care solution or air dry their lens cases every time after use, 68 per cent cleaned their lens cases less than once per week and 61 per cent didn’t change their lens cases regularly.
The study also showed that contact lenses used by occasional wearers were more likely to be contaminated with ocular pathogenic microorganisms – possibly because contact lenses that are left in the case (which may be contaminated), without being used for a period of time, provide a favourable environment for microorganisms.
These lens case findings are important because the ability of acanthamoeba to survive in contaminated lens cases has been reported by Cheng et al,4 and inadequate cleaning of the lens case has been cited as a risk factor for infection with acanthamoeba by Houang et al.5 It would therefore be worthwhile for all practitioners to take special care to instruct patients on the importance of lens case hygiene, as well as hygiene for the lenses themselves.
Another recent study6 examined the beliefs and attitudes of patients and practitioners on proper lens care compliance. Interviews of 350 eye care practitioners (ECPs) and 700 patients were conducted in Australia, Singapore, Malaysia, Hong Kong, China, Taiwan and South Korea.
ECPs were (rightly) sceptical about consumers’ compliance with cleaning instructions. Only 10 per cent of ECPs believed consumers were strictly compliant with cleaning instructions, even though 36 per cent and 35 per cent of the consumers claimed they were strictly compliant with instructions from packaging and ECPs respectively. However, in reality consumers’ lens care habits were not up to standard. Although consumers stated that they devote 2.9 minutes per day to lens care, which should theoretically be sufficient, nearly 70 per cent of consumers did not clean their lens case every day, and 50 per cent of them kept their lens case longer than three months.
Most (68 per cent) of the ECPs believed consumers had not read the cleaning instructions. Far more (90 per cent) of the consumers claimed they did read instructions, although most (60 per cent) did admit they only read the instructions the first time they buy a new lens care product.
Risk? What risk?
In the study the patients’ excuse for non-compliance is their ‘busy lifestyle’. However, ECPs believed complacency and insensitivity to potential risk are also major contributors.
As practitioners we know the risks and know what to look out for. In the study ECPs accurately stated that ‘no rubbing and rinsing’ and ‘not cleaning the lens case’ are the most common mistakes leading to eye infections. However, these two behaviours are regarded by consumers as the least common factors causing infection. This shows that consumers are taking these risks too lightly.
Can you hear me?
Clearly, patient education is the key to understanding the risk and doing something about it. Repetition of risk factors and what to avoid at each and every patient visit is a vital component of patient care.
But there may be a hidden problem – are they hearing us?
One of the most startling findings from the interview study is that patients and ECPs disagreed widely on what was actually being done in patient education: ECPs believed that instructions on proper lens care were given 2.8 times per annum, while patients believed they had only been given 1.6 times per annum. ECPs believed they had given information in 2.7 ways, vs consumers: 1.6 ways.
Recently, the IER Matrix Study found that hydrogen peroxide was the only solution to virtually eliminate solution-induced corneal staining with silicone hydrogel lenses.7 Most (83 per cent) of the ECPs said that they had recommended hydrogen peroxide to their patients, but only 31 per cent of the customers believed they had ever received the recommendation.
Finally
Perhaps the greatest challenge to consumer compliance is getting patients to understand the importance of a good cleaning regimen (especially lens cases!), and to comply with contact lens care instructions provided by eye care practitioners and product packaging.
The Asia Pacific research shows that patients do not understand the high risk of some types of behaviour, and perhaps of even more concern, that they are just not hearing the practitioner when instructions and reminders are given. It suggests that practitioners need to find new ways to engage with patients to ensure that instructions and warnings are heard and fully understood.
As we said in the Guidelines coming out of the Summit – patient contact lens hygiene should be reinforced at repeat visits, by demonstration and observation and appropriate repetition of lens care instructions.
Professor Brien Holden, BAppSc PhD DSc OAM, is CEO and Director of the Institute for Eye Research, CEO of the Vision Cooperative Research Centre, founder and Director of the Cornea and Contact Lens Research Unit at the School of Optometry and Vision Science, University of New South Wales, and was Director of the Cooperative Research Centre for Eye Research and Technology.
References
- Lam DS, Houang E, Fan DS, Lyon D, Seal D, Wong E; Hong Kong Microbial Keratitis Study Group. Incidence and risk factors for microbial keratitis in Hong Kong: comparison with Europe and North America. Eye 2002;16:608-18.
- Stapleton F, Keay L, Edwards K, Naduvilath T. Incidence of contact lens related microbial keratitis: 6 month data. In: Trans Cornea and Eyebank Meeting; Sydney, Australia 2005
- Yung MS, Boost M, Cho P, Yap M. Microbial contamination of contact lenses and lens care accessories of soft contact lens wearers (university students) in Hong Kong. Ophthalmic and Physiological Optics. 2007;27:11-21.
- Cheng KH, Leung SL, Hoekman HW, Beekhuis WH, Mulder PGH, Geerards AJM, Kijlstra A. Incidence of contact-lens-associated microbial keratitis and its related morbidity. Lancet 1999;354, 181-185
- Houang E, Lam D, Fan D, Seal D. Microbial keratitis in Hong Kong: relationship to climate, environment and contact-lens disinfection. Trans R Soc Trop Med Hyg 2001;95, 361-367
- Presentation by Venice Ng, Asia Pacific Contact Lens Care Summit, Singapore 2007, of a survey conducted by an independent market research company, Oracle-Added Value and funded by Advanced Medical Optics.
- Carnt NA, Willcox MDP, Evans VE, Naduvilath TJ, Tilia D, Papas EB, Sweeney DF, Holden BA. Corneal staining with various contact lens solutions – Silicone hydrogel lens combinations and significance: The IER Matrix Study. Contact Lens Spectrum, September, 2007
