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Keywords:

  • contact lenses;
  • contact lens solutions;
  • keratitis;
  • patient compliance;
  • patient education

Abstract

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

Contact lens hygiene has long been recognised as key to the prevention of contact-lens associated infection and inflammation. Microbial keratitis (MK) is the only serious and potentially sight-threatening contact lens adverse event. International studies including recent research in Asia Pacific show that MK is rare but, as the consequences can be severe, it is important to minimise the risk factors. Studies continue to show that one of the key risk factors is lens and lens case hygiene. Therefore, it is also useful to review the behaviour of our patients, to see how closely they follow the recommended hygiene practices. Recent studies in various regions have shown that patients’ lens care habits do not meet a required standard.

Patients can become complacent and thus non-compliant with lens care instructions. Furthermore, they do not understand the high risk of some behaviour and they are not hearing the practitioner when instructions and reminders are given. Further education is important to improve patient compliance and safety. The Asia Pacific Contact Lens Care Summit held in Singapore urged the industry and practitioners to restore the emphasis of proper lens care, including the ‘rub and rinse’ technique, and developed a new set of guidelines to help eye-care professionals educate their patients on the importance of proper contact lens care to avoid eye infections. The summit also presented the latest research on how to avoid corneal staining, another important element of contact lens care. This review provides a summary of the summit presentations and the science behind these guidelines.

The eye has a range of natural defence systems, which very effectively protect the eye's tissues from inflammation and infection. The placement of a contact lens on the eye places an added burden on these systems, which sometimes results in an adverse response or event. Knowing the risk factors for these events, typical patient behaviour that might contribute to these, and the best practice care and management guidelines, will help practitioners to improve patient outcomes.

ADVERSE EVENTS

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

Microbial keratitis (MK) is the only serious and potentially sight-threatening contact lens adverse event and is the only infection related to contact lens wear. All other events are either inflammatory or physiological in nature or are mechanically induced. The inflammatory events such as contact lens-induced peripheral ulcer (CLPU), contact lens-induced acute red eye (CLARE) or infiltrative keratitis (IK) may be associated with the presence of bacteria and their toxins on the eye, the lids or the contact lens but are not sight threatening.1

MK is caused by microbial infection of the cornea. The presentation of MK can vary, depending on the type and virulence of the micro-organism and the stage at which the patient presents. In general, excavation of the corneal epithelium, Bowman's layer and the stroma is seen, with serious necrosis and infiltration of the underlying tissue.1 Anterior chamber reaction is often observed in the active stage. The patient will have moderate to severe pain of rapid onset, with severe redness of the eye, blurred or hazy vision, discharge and photophobia. A key characteristic of MK is that the symptoms and signs worsen with time.

CONTACT LENS WEAR

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

Myopia is a rapidly growing epidemic. It is estimated that the number of myopes in the world will grow from 1.6 billion now to 2.5 billion by 2020.2 In Asia in particular, a combination of heredity and changing lifestyles is bringing about an increased incidence of myopia. For example, in Singapore, a series of studies has shown an increase in myopia in males aged 15 to 25 years, from 26 per cent in the late 1970s to 83 per cent in the late 1990s.3,4 In Taiwan, a nationwide survey showed that the prevalence of myopia among schoolchildren increased from 20 per cent at seven years of age to 61 per cent at 12 years and 81 per cent at 15 years.5

With the increase in myopia throughout the world and particularly in Asia, we are also seeing an increase in contact lens wear and thus unfortunately, an increase in contact lens-related infections. Reports of increased numbers of cases of infection in countries in the Asia Pacific region have been of concern to local practitioners.

Recent studies have examined the rates of contact lens complications.6,7 In comparing rates of MK with extended wear (EW) in different regions, it is clear that while there may have been an increase in the absolute number of cases in the Asia Pacific, the rates per population remain very low and are consistent between regions and across all soft lens types (Figure 1). Thus, what we are seeing internationally is reflected in the Asia Pacific region.

image

Figure 1. MK with EW: annual incidence rates

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One major study in the region, the Australian and New Zealand Microbial Keratitis Study,7 captured all new cases of presumed MK identified between October 2003 and September 2004. This large-scale collaborative research project was designed to assess the incidence of MK with different contact lenses and modes of wear, and to assess risk factors associated with infection. The study involved surveillance of all cases of contact lens-associated keratitis presenting to private and hospital-based ophthalmic practitioners and a population-based telephone survey of 30,000 households in Australia and 7,500 in New Zealand.

The study reaffirmed that contact lens-related infections are rare, affecting approximately four in 10,000 daily wear and 20 in 10,000 extended wear contact lens wearers annually.7

ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

It has been suggested that inflammatory events such as CLPU, CLARE and IK are a markers of increased risk for the occurrence of MK or can progress to MK.8

Several authors8,9 have put forward an argument that symptomatic contact lens-related keratitis should be considered as a part of a disease continuum encompassing any event that aggregates inflammatory cells in the cornea. It is also possible that corneal inflammatory events could provide the trauma or break in the epithelium required to allow the microbes to invade the epithelium and result in an MK event. However, it is the bacterial type not epithelial trauma that dictates inflammatory versus infective events.10,11 Willcox and colleagues11 used the corneal challenge of a needle scratch in a mouse model and applied a range of inocula, including Pseudomonas aeruginosa, Haemophilus influenzae, Serratia marcescens, Stenotrophomonas maltophilia or Aeromonas hydrophila isolated from human cases of MK or CLARE. The results showed that strains isolated from inflammatory events such as CLARE did not cause infection, although this may not exclude organisms of low virulence causing less severe microbial keratitis.

The recent Stapleton review of risk factors12 associated with sterile infiltrates in silicone hydrogel EW identified the following factors: history of prior lens-related corneal inflammation, initial period of adaptation, limbal redness, corneal staining, younger age (under 25 years), older age (over 50 years), smoking, high ametropia, shorter duration of EW and bacterial contamination of the storage case. While inflammatory events do not appear to be a risk factor for events of MK, they are a risk factor for further inflammatory events.

While of concern to patients and practitioners, inflammatory events are self-limiting and benign. In contrast, prompt attention and aggressive treatment are essential for suspected corneal infection, as MK is a truly infectious process and displays rapid growth of bacteria in the corneal tissue.13 In practice, any ulceration of the cornea should be treated as though it might be a true MK and appropriate antibiotic therapy given. Indeed, failure to appropriately treat MK rapidly has been shown to be a major risk factor in developing severe disease.14

CAUSES AND RISK FACTORS

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

Some of the most important results of the research into contact lens infections are the identification of risk factors associated with the disease.

The risk of microbial keratitis associated with contact lens wear is increased with overnight contact lens use.6,7,15–20 Closure of the eye causes changes to the ocular defences which parallel those seen with contact lens wear, and sleeping in lenses means the effects may be additive. An important finding of the Australian and New Zealand Microbial Keratitis Study7 and the parallel study carried out in the UK21 is that overnight wear persists as the major risk factor regardless of the soft lens type worn.

Recent research showed that one in three eye health problems suffered by lens wearers is a direct result of improper lens care and cleaning.22 Indeed, adverse events in general, including both infective and inflammatory conditions, are more likely where there is contamination of the lenses. Sankaridurg and colleagues23 found that colonisation of soft contact lenses with pathogenic bacteria, especially Gram-negative bacteria and S. pneumoniae, appears to be a significant risk factor leading to inflammatory events. In the Australian study, significant associations were identified between MK and lens hygiene practices, smoking, overnight wear and male gender.22 This confirms earlier epidemiological studies, which have also highlighted lens and case cleaning,6,12,19 smoking15,16,20 and male gender12,15 as important risk factors. Socio-economic status is also a factor, though puzzlingly in the Australian study,24 high socio-economic class was the risk factor, while conversely, in other studies,18,21 it was found to be low.

Also of concern is the contamination of solutions. Commercially available preserved saline solutions became contaminated during normal use.25 The contaminants were predominantly gram-positive bacteria, representing normal ocular or skin flora.

PATIENT BEHAVIOUR

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

Contact lens hygiene has long been recognised as the key to the prevention of contact-lens associated infection and inflammation, however, as all practitioners know, patients may become complacent and thus non-compliant with lens care instructions. Recent studies, such as that conducted by Morgan,26 show that compliance is an issue with many patients. His survey of contact lens use in Europe found that only 0.3 per cent of daily wearers and 2.7 per cent of extended wearers were fully compliant for all 14 steps identified for correct lens care. Many wearers stretched the use of their contact lens products by using lenses for too many days, sleeping in lenses when daily wear use only had been prescribed, sleeping in lenses for too many nights in the case of extended wear, and topping up solutions rather than discarding the solution from the lens case each time and refilling with fresh solution. Only a minority of wearers in the study cared for their contact lens cases correctly and as this is a known risk factor for ocular infection, the need for much improved management of contact lens cases is a key message. Similarly, a survey by the US Contact Lens Council27 found that 44 per cent of patients always or occasionally topped up their contact lens solution and 54 per cent did not clean their lens case after each use. In addition, 49 per cent wore lenses for longer than recommended, although this has not been confirmed as a risk factor for corneal infection or inflammation.

Two recent Asia Pacific studies further demonstrate current patient behaviour.

Hong Kong study

In Hong Kong, 101 young, university-based, asymptomatic soft contact lens wearers were recruited.28 All subjects were interviewed regarding their contact lens wearing history and hygienic practices and the lenses, solutions and cases of the subjects were tested for microbial contamination.

In this study, the lens case was the most frequently contaminated item and yielded the widest range of bacterial isolates. This may be because contact lens wearers usually pay less attention to case hygiene than lens hygiene. According to the interviews, over half of the subjects (58 per cent) did not discard lens care solutions or air dry their lens cases every time after use (the recommended procedure), 68 per cent cleaned their lens cases less than once per week and 61 per cent did not change their lens cases regularly (at least every three months is recommended). Lack of cleaning and replacement allows the lens cases to become a stagnant environment. Such an environment is more favourable for the formation of biofilm than contact lenses.29 This is of concern because biofilm on the case surface provides a reservoir for the adhesion of further micro-organisms to lenses30 and physically protects bacteria from disinfectants.31

Care of the lens case is of particular relevance because non-compliance has frequently been associated with contamination of the case32,33 and even infection in contact lens wearers.29 The ability of Acanthamoeba to survive in contaminated lens cases has been reported by Cheng and associates34 and failure to clean the lens case adequately was cited as a risk factor for infection with Acanthamoeba by Houang and co-workers.35

Another interesting factor in lens care is that the results of the Hong Kong study show that contact lenses used by occasional wearers were more likely to be associated with ocular pathogenic micro-organisms. This may be because contact lenses that are left unused in the (probably contaminated) case for a period provide a favourable environment for the attachment of micro-organisms and build-up of biofilm. By contrast, a recent study has confirmed a dose-dependent effect of wear showing that part-time (two days per week) daily lens use has a lower risk of disease compared with six or seven days.21

In the Hong Kong study, the patients were university students and would be expected to be well educated and thus cognisant of the potential risk of poor lens hygiene, yet the findings of this study demonstrate that contact lenses and lens care accessories are not well maintained by the wearers. Therefore, regular reviews and reinforcement of lens care procedures for the use and care of contact lenses is essential to protect patients. In particular, special care should be taken to instruct patients on the importance of lens case hygiene, as well as hygiene for the lenses themselves.

Asia Pacific survey

In the second study, a major survey of Asia Pacific markets was conducted to investigate the disconnection between the beliefs and attitudes of patients and eye-care practitioners (ECP) on proper lens care compliance.36

The research was conducted in October 2007 by an independent market research company, Oracle-Added Value, in Australia, Singapore, Malaysia (Kuala Lumpar/Petaling Jaya), Hong Kong, China (Shanghai), Taiwan (Taipei) and South Korea (Seoul). In each location, panels of 50 ECPs and 100 consumers were interviewed: the ECP panels were put together from a random sampling of local optometrist associations or business directories, and the consumer panels from a random sampling based on the population distribution.

The Asia Pacific survey shows that ECPs are sceptical about consumers’ compliance with cleaning instructions, with only 10 per cent of them believing consumers were strictly compliant with cleaning instructions, while 36 and 35 per cent of the consumers claimed they were strictly compliant with instructions from packaging and ECPs, respectively. In reality, consumers’ lens care habits are not up to standard. Although consumers stated that they devote 2.9 minutes per day to lens care, which theoretically should 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, whereas 90 per cent of the consumers claimed they did read instructions. Most consumers (60 per cent) did admit they only read the instructions the first time they bought a new lens care product.

SOLUTIONS

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

In November 2007, the Institute for Eye Research (IER) conducted a series of tests to evaluate the efficacy of various regimens that might be recommended for hygienic lens care.37

In regimen A, lenses were neither rubbed nor rinsed before disinfection; in regimen B, lenses were rinsed for five seconds per lens surface before disinfection; and in regimen C, lenses were rubbed and rinsed before disinfection. Disinfection of the lenses followed the manufacturers’ recommended minimum disinfection time (four or six hours depending on solution type). Solutions tested included Complete MoisturePlus, Opti-Free Replenish, AQuify and ReNu MultiPlus. Challenge micro-organisms were the standard panel of organisms, which include Pseudomonas aeruginosa, Staphylococcus aureus, Fusarium solani, Candida albicans, as well as a strain of Acanthamoeba polyphaga.

The International Organization for Standardisation (ISO) has set up standard disinfecting regimens that solutions must pass. Under one disinfection criterion called the Stand Alone test and published as ISO standard 14729,38 contact lens disinfecting solutions are required to reduce the load of specific strains of microbes in the solution by specific amounts (one log unit reduction for Fusarium and Candida; three log unit reduction for Pseudomonas aeruginosa, Serratia marcescens and Staphylococcus aureus) and there is no requirement for a rub/rinse step. If solutions passed this Stand Alone test, they did not have to meet the ‘Regimen Criteria’ that required the solutions to perform to certain standards (including reductions in microbe numbers after rubbing and rinsing the lenses). Under the regimen test, less than 10 colony-forming units of bacteria or fungi are allowed to remain on the lens surface.

Recently, there have been recalls of some of these newer no-rub solutions due to apparent lack of efficacy and consequent increases in specific types of microbial keratitis. In 2006 Bausch & Lomb globally recalled its solution, ReNu MoistureLoc,39 following epidemiological evidence that this solution was linked to an increase in microbial keratitis caused by Fusarium sp., including outbreaks in Singapore40,41 and the USA.42 While ReNu MoistureLoc met the ISO Stand Alone disinfection criteria and was reported as being very effective against bacterial types,43,44 it appears that a combination of the novel ingredients in MoistureLoc and a certain amount of non-compliance by users brought about this increase in Fusarium keratitis.

Another recent recall of a MPS solution was made due to an apparent increased risk of acanthamoebic keratitis. Advanced Medical Optics globally recalled Complete MoisturePlus from sale in 2007, following a report that demonstrated an increased rate of acanthamoebic keratitis that was associated with the use of Complete MoisturePlus.45 No existing multipurpose solutions in the current market are required by US FDA to be tested against Acanthamoeba.

While contact lens manufacturers have responded to market pressure by producing more easy to use, no rub solutions, this may not be the optimum lens care for lens hygiene and ocular safety.

In the IER study across four solutions and three lens types, in most cases, the addition of the ‘rub and rinse’ step significantly reduced the microbial load on the lens. Compared to rinsing only:

  • 1
    Pseudomonas aeruginosa was reduced by a further two to three log units with ‘rub and rinse’.
  • 2
    Staphylococcus aureus was reduced by at least a further two log units with ‘rub and rinse’.
  • 3
    Both fungi Fusarium solani and Candida albicans were reduced by a further one to two log units with ‘rub and rinse’.
  • 4
    Acanthamoeba polyphaga was reduced by up to a further 0.5 log unit with ‘rub and rinse’.

This study has demonstrated that rubbing combined with rinsing and appropriate time for disinfection adds a significant safety margin (up to 100,000 times). In another study, Cho and colleagues46 compared the effectiveness of rub versus no-rub cleaning of 300 soft contact lenses, which were artificially contaminated with serum albumin, hand cream and mascara. Their results showed that cleaning the soft lens without rubbing was ineffective in removing loosely-bound deposits. Their work supports the view that contact lens wearers should be encouraged to rub their lenses when cleaning. The US Food and Drug Administration (FDA) Ophthalmic Devices Panel of the Medical Devices Advisory Committee has now recommended the ‘rub and rinse’ technique as best practice in contact lens care.

Furthermore, at the 111th meeting of the US FDA Ophthalmic Devices Panel on June 10 2008,47 the panel concluded that the current regimen test should be revised to improve predictability of real world performance, including testing a lens in the case with the solution, without rubbing, without rinsing and with biofilm. They also recommended that a realistic ‘rub and rinse’ time should be included in labelling, along with explanations of the reasons contact lens wearers should rub and rinse.

While ‘rub and rinse’ is the primary recommendation, one alternative is the use of a solution with hydrogen peroxide. Carnt and colleagues48 have shown that the use of hydrogen peroxide is able to reduce the risk of corneal inflammation by a factor of 10 compared to MPS. Moreover, hydrogen peroxide is more effective in killing rare organisms such as Acanthamoeba,49 although longer exposure time to peroxide is required to fully eliminate the cysts. It was suggested that the cysticidal activity of hydrogen peroxide could be improved if neutralisation were delayed.50 Hydrogen peroxide also offers another benefit, as it is currently the only solution to virtually eliminate solution-induced corneal staining with silicone hydrogel lenses.51,52

Corneal staining is an important in-practice tool for evaluating the state of the corneal epithelium. While minimal corneal staining often occurs in contact lens wear,53 moderate amounts of controllable staining should always be avoided, especially given the links that have been established between solution-induced corneal staining or ‘SICS’ and low grade corneal inflammation and discomfort. IER researchers have previously shown that SICS is associated with three times increased risk of corneal inflammation54 and decreased comfort.55

The introduction of silicone hydrogel contact lenses has had an unexpected ocular consequence. About 2004, corneal staining in response to particular silicone hydrogel materials and solutions became of concern56 and practitioners and patients had to be wary of possible ‘combination’ effects. Unfortunately, lens/solution interactions were not predictable according to preservative type and concentration.57

Structurally, silicone hydrogel lenses are more complex than conventional hydrogels, with fluorine and silicone for oxygen permeability and other components and surface treatments to improve lens wettability. At the same time, lens care solutions are themselves complex, with buffers, chelating agents, surfactants, isotonicity agents, hygroscopic agents and preservatives. Recently, we have also seen the release of new, wetting, comfort-enhancing multipurpose solutions, which have other ingredients. Finally, solutions interact with the complex tear film.

Understanding which combinations may cause problems is important for practitioners in providing appropriate advice to their patients.

A number of studies examined the combinations to present lens/solution ‘grids’, detailing the interactions. These include Lyndon Jones,56 the Andrasko Staining Grid (http://www.staininggrid.com) and the Itoi Grid (http://www.staininggrid-japan.com), where lenses were soaked overnight in a particular solution and the average percentage of corneal staining (by area) after two hours of wear the following day was recorded.

The Institute for Eye Research Matrix Study, first published in the September 2007 issue of Contact Lens Spectrum51 and updated in March 2008,52 examined five leading brands of lenses used in combination with four brands of disinfecting solutions (Table 1).

Table 1. IER Matrix Study lenses and solutions
Contact lensesComposition
Acuvue Advanc (Johnson and Johnson Vision Care Inc)47% water, galyfilcon A, PVP, low water/ non-ionic (FDA I), Dk 60, Dk/t 86
Acuvue Oasys (Johnson and Johnson Vision Care Inc)38% water, senofilcon A, PVP, low water/ non-ionic (FDA I), Dk 103, Dk/t 147
O2Optix (CIBA Vision)33% water, lotrafilcon B, plasma, low water/ non-ionic (FDA I), Dk 110, Dk/t 138
PureVision (Bausch & Lomb)36% water, balafilcon A, plasma, low water/ ionic (FDA 3), Dk 91, Dk/t 110
Night and Day (CIBA Vision)24% water, lotrafilcon A, plasma, low water/ non-ionic (FDA I), Dk 140, Dk/t 175
Contact lens solutionsComposition
AO Sept Plus Clear Care (CIBA Vision)Sodium chloride, phosphate buffer system, pluronic surfactant, phosphonic acid, hydrogen peroxide 3%,
AQuify MPS Focus AQuify (CIBA Vision)Sorbitol, tromethamine, dexpanthenol, pluronic F127 surfactant, sodium phosphate dihydrogen buffer, disodium edetate, polyhexadine 0.001%
Opti-Free Express (Alcon Laboratories Inc)Sodium chloride, sorbitol, AMP-95, boric acid/ sodium citrate buffer, tetronic 1304 surfactant, disodium edetate, 0.001% polyquad, 0.0005% aldox
Opti-Free RepleniSH (Alcon Laboratories Inc)Sodium chloride, sorbitol, AMP-95, boric acid/sodium citrate buffer, tetronic 1304 surfactant, disodium edetate, 0.001% polyquad, 0.0005% aldox

The study involved 800 experienced and new contact lens wearers in 20 groups of 40, who used each type of silicone hydrogel lens bilaterally in conjunction with each type of multipurpose solution and were monitored over three months. Clinicians indicated the presence of SICS (Figure 2). The IER Matrix Study defined SICS to avoid confusion with other corneal staining phenomena. There are two manifestations of solution-related staining, ‘diffuse punctuate’ and ‘peripheral annular’ and they are easily differentiated from corneal staining resulting from other causes.

image

Figure 2. Solution-induced corneal staining differentiation A. Diffuse staining spread over most of the cornea. If severe, there can be linear areas of coalescent punctate staining. B. Peripheral staining, usually a continuous paralimbal/limbal annulus. We considered staining peripheral when the average extent of staining in the peripheral zones was more than 0.5 of a unit higher than in the central zones. C. Dehydration staining, located mainly inferiorly and contributed to by partial blinking and lagophthalmos. It may also occur in the superior cornea adjacent to the upper lid margin due to an unstable tear meniscus. It generally presents in bands and is located in the mid-peripheral cornea. D. Limbal transition pooling. Circumferentially arranged radial spokes of fluorescein pooling at the anterior edge of the limbal transition zone occurs in some patients.

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The study reveals that each solution-silicone hydrogel lens combination presents a unique ocular situation; some causing SICS in a high percentage of wearers, others causing SICS in a low percentage of wearers, with hydrogen peroxide causing almost none (Table 2).

Table 2. IER Matrix including ‘night and day’ lenses (percentage of patients per month)Thumbnail image of

Multipurpose solutions

Opti-Free Express and Replenish were in higher quartile ranges than were peroxide and AQuify MPS for both Acuvue Oasys and O2Optix.

Opti-Free Replenish was also in higher quartile ranges than Opti-Free Express for Acuvue Oasys and O2Optix.

AQuify MPS was in the higher quartile range for PureVision.

Hydrogen peroxide

Hydrogen peroxide caused far less corneal staining with silicone hydrogels than did any of the multipurpose solutions (MPS) (for all lens types combined, p < 0.001).

Lenses

PureVision demonstrated statistically significant staining with MPS systems but not hydrogen peroxide. (PureVision versus other lens types with MPS, p < 0.001).

Acuvue Advance had the lowest frequency of staining for MPS compared to all other lens types (p < 0.001).

Night & Day is in the lowest quartile, with Clear Care and AQuify in the highest quartile range for both Opti-Free products, along with PureVision and Oasys.

PATIENT EDUCATION

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

While a hydrogen peroxide solution is very effective in contact lens disinfection, a further problem was demonstrated in the Asia Pacific survey,36 in which 83 per cent of the ECPs stated that they recommended hydrogen peroxide to their patients but only 31 per cent of the customers believed they had ever received the recommendation.

This confirms that instructions provided by the ECP may not be registering with patients. They can become complacent and may not hear the instructions or reminders provided. Also in the survey, ECPs and consumers agreed on when and how to provide lens care instructions but ECPs believed the instructions on proper lens care were actually given more frequently than consumers perceived (ECP: 2.8 times versus consumers: 1.6 times per annum) (Figure 3) and in more varied ways (ECP: 2.7 ways versus consumers: 1.6 ways) (Figure 4).

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Figure 3. When proper lens care is discussed with patients

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Figure 4. Ways patients receive information about proper care

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Consumers are also insensitive to potential risk. In the survey, ECPs accurately stated that ‘no rubbing and rinsing’ and ‘not cleaning the lens case’ are the most common mistakes in hygiene, which may lead to ocular infection, however, these two forms of behaviour were regarded by the consumers as the least common factors causing infection (Figure 5). This is a vital finding, showing that consumers have taken these risk factors too lightly and thus increased their exposure to risk. It also demonstrates the need for continual education of patients by ECPs.

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Figure 5. Lens care behaviour leading to eye infection

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Non-compliance is a complex problem that involves patient knowledge, attitudes and beliefs and resources.58 Claydon59 found that most patients are unintentionally non-compliant, due to misunderstanding, forgetfulness or poor instruction and that only a small percentage were intentionally non-compliant due to cost, inconvenience, ignorance or denial of the risk.

Clearly, a better understanding of wearers’ beliefs, behaviour and motivations may assist in developing effective guidelines and patient communication strategies. Claydon59 developed a model of general guidelines to enhance compliance, detailing three interdependent areas comprising the contact lens patient, the clinic and practitioner, and the lens care recommendations. While there has been an emphasis on recommendations, clear instructions must be combined with an understanding of the knowledge, preferences and expectations of the patient and with enhancing the practitioner-patient relationship. Good communication is essential for compliance.

While the practitioner can make a major contribution to successful contact lens wear by careful patient selection and lens fitting, the patients must play their part in monitoring and supporting their ocular health.

Patients should check every morning and night to ensure that their eyes ‘look good, feel good and see well’.60 If there are any problems, such as redness, watering, discomfort or pain, patients should immediately remove their lenses and contact their practitioner as soon as possible. Some patients may feel that if the lens does not feel quite right, sleeping in lenses may alleviate the discomfort or perhaps they just do not take the trouble to remove their lenses. This must be avoided. Also importantly, patients should not sleep in lenses if they feel unwell, as they may be at higher risk of adverse events such as CLARE.61 If patients remove their lenses for any time, they should be disinfected before they are reinserted or be replaced with new lenses.

The Australia and New Zealand MK study7,62 found that those who developed infections were more likely to have purchased their contact lenses over the internet, highlighting the need for professional advice and education on contact lens prescribing.

The importance of patient compliance should be reiterated at every visit, as it has been shown that compliance levels decrease with experience, and reinstruction increases compliance levels.63 It is also a good idea if patients are given documentation to take home with them. The documentation should provide clear instructions in layman's terms on guidelines to follow to avoid complications, information on the support network available, and a description of the possible repercussions of non-compliance. It is also important to foster patient loyalty so that patients will return for follow-up care and will contact the practitioner promptly if there is a problem.

It must be noted that while the practitioner-patient relationship and communication are essential to compliance, practitioners do not need to find entirely novel ways to engage with patients. Studies by Claydon, Efron and Woods64 and Yung and associates65 show that compliance enhancement strategies, such as videos, posters, a health care contract or free solutions, had little effect on compliance levels.

Industry, too, plays a role in ensuring contact lens patient safety and compliance, by providing the best possible products and by raising awareness of good lens care practice among patients. The revision of the ISO standard will be an important first step in improving products. As recommended by the FDA Ophthalmic Devices Panel, the improvement of written product instructions is already taking place, for example, with the development of an easy to use cautionary product statement to communicate the importance of patient compliance by the US Contact Lens Institute, an association of manufacturers.

ASIA PACIFIC CONTACT LENS CARE SUMMIT

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

In 2007, the Asia Pacific Contact Lens Care Summit was held in Singapore. Delegates, including leading eye health clinicians, researchers and academic experts, developed a new set of guidelines to help eye-care practitioners educate their patients on the importance of proper contact lens care to avoid eye infections. The guidelines emphasise that contact lenses are safe if they are used properly, and offer instructions on their use, maintenance and storage.

GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

We, the delegates at the 2007 Contact Lens Care Summit, are strongly of the view that contact lens care and its proper implementation are critical to the safety and efficacy of contact lens wear.

We make this statement in support of improving safety for all contact lens wearers and to encourage adoption of these guidelines that are aimed at improving practitioner awareness and increasing lens care efficacy and patient compliance.

We consider that:

  • 1
    Contact lenses are a safe and effective way of correcting vision when used and cared for properly.
  • 2
    Care and maintenance of contact lenses and cases are of major importance in avoiding the very rare but serious problem of corneal infection.
  • 3
    Contact lens care is critical in optimising the performance of contact lenses and avoiding inflammation and other side-effects.
  • 4
    Hydrogen peroxide, when used appropriately, has been shown to be a very safe disinfection system and, thus far, the system most conducive to continued lens biocompatibility and performance.
  • 5
    Rubbing and rinsing contact lenses with a multipurpose solution is a very important way of significantly reducing the microbial challenge to the contact lens wearing situation and ideally should be used both before and after lens disinfection and storage.
  • 6
    Contact lens cases are a major potential source of infectious organisms. Practitioners and corporations are urged to consider every measure possible to reduce potential contamination, including supplying new cases with every lens care pack, encouraging disposal of ‘old’ cases, producing contamination resistant cases, encouraging the use of cases that are easy to clean and giving clear instructions on case hygiene and storage, when the cases are not in use.

We urge practitioners and the industry to restore emphasis to the importance of contact lens care for the sake of all contact lens wearers.

We emphasise the role of the practitioner in ensuring that patients are properly informed and understand the details of appropriate care of the lenses they prescribe, including taking responsibility for instructing patients in appropriate care techniques for the lenses prescribed.

We ask that industry and practitioners make all possible efforts to clarify and simplify instructions for patients, so that they are easy to understand and carry out.

We ask all the organisations involved in contact lens education, such as IACLE (International Association Contact Lens Educators), contact lens societies, eye research institutes, university departments and professional bodies, to revisit the issue of contact lens care and to emphasise in all educational programs that proper care and maintenance are very important parts of contact lens safety and success.

We suggest adoption of the following guidelines for appropriate contact lens care and maintenance.

Contact lens hygiene fundamentals

  • 1
    Contact lens disinfection systems should be effective against bacteria, fungi, viruses and amoebae.
  • 2
    Every time a contact lens is handled, it should be with clean, washed and dried hands.
  • 3
    Any time a contact lens is removed from the eye, it should be properly disinfected.
  • 4
    Safety is enhanced significantly by rubbing and rinsing contact lenses both prior to and following storage.
  • 5
    Patients should never ‘top up’ that is, add additional solution to the solution already in the case.
  • 6
    When contact lenses have been stored for more than seven days, regardless of whether peroxide or multipurpose solutions is used, lenses should be effectively redisinfected before the next use.
  • 7
    Hydrogen peroxide is considered to be a very safe solution, however, patients using hydrogen peroxide for disinfection should be advised to use unit dose sterile saline or other sterile saline-based solutions for rinsing their lenses prior to lens insertion.
  • 8
    Patients should be advised strongly to adhere to the lens wearing and replacement schedules prescribed by their practitioners.
  • 9
    The industry and practitioners are urged to make all instructions for contact lens care systems simple, easy to remember and effective.
  • 10
    Purchasing lenses over the internet has been shown to have a higher risk of infection, presumably because of the absence of practitioner monitoring and instruction.
  • 11
    Medical practitioners and associated health care professionals should be provided with up-to-date advice on contact lens care and the latest treatment imperatives for contact lens-related complications.

Patient management

  • 12
    Patients should be told to wash their hands every time they handle their contact lenses or contact lens cases, preferably with appropriate (non-moisturising, non-residue) soap or disinfectant and to dry their hands with lint-free tissues or cloths.
  • 13
    Practitioners should note on their records the type of contact lens care system and instruction information given to each patient, and this information should be updated at each visit.
  • 14
    Patient contact lens hygiene should be monitored at repeat visits, by demonstration and observation and appropriate reinforcement of lens care instructions.

Contact lens case hygiene

  • 15
    Contact lens case hygiene is extremely important.
  • 16
    Contact lens cases should be cleaned and dried after every use.
  • 17
    Contact lens wearers should be told how to clean and disinfect contact lens cases and to dry them with a clean lint free cloth, if that is not contraindicated for the type of case.
  • 18
    The industry should be encouraged to make contact lens cases that are cleaned easily.
  • 19
    The industry is encouraged to continue development and use of improved, anti-bacterial and disposable contact lens cases.
  • 20
    Contact lens solution manufacturers should make available a new case with every bottle of contact lens disinfecting solution and patients should discard their old case and use the new case every time a new bottle of disinfecting solution is used.

Tap water and other high risk situations

  • 21
    Patients should be informed that water is a very common source of very infectious and potentially damaging micro-organisms that can produce sight-threatening infections and [be advised] to never use tap water to store, clean or rinse their contact lenses.
  • 22
    Patients should also be reminded to avoid splashing water directly into their eyes, contact lenses or contact lens cases.
  • 23
    Patients should be advised to close their eyes firmly while showering or washing their faces with water.
  • 24
    Practitioners should emphasise that one of the highest risk occasions for contact lens wearers is when on vacation and that an appropriate ‘travel kit’ should be carried and used and [patients should] be especially vigilant with regard to contact lens care and disinfection.
  • 25
    Manufacturers of contact lens care systems should provide smaller bottles of disinfectants that last a shorter time and that comply with current travel restrictions on solution container volume.
  • 26
    Practitioners should advise patients that exposing lenses to potential contamination from swimming pool or spa water is another high risk occasion for contact lens wearers and that goggles should be worn while swimming. Care should be taken to avoid spa or pool water being splashed in the eyes. For emphasis, patients should be advised that if they wish to remove their lenses before or during such activities, they must be properly cleaned and disinfected before being reinserted.
  • 27
    Practitioners should inform patients that storing their contact lenses in the bathroom carries a high risk of airborne contamination and that special care needs to be taken to avoid atmospheric contaminants, especially by avoiding leaving containers open.
  • 28
    Patients should never reuse the solution in a contact lens case.

Patients should be told never to refill smaller contact lens solution containers with solution from a larger container. Smaller containers should be made difficult to refill.

Summit delegates

Professor Brien Holden, University of New South Wales; CEO, Institute for Eye Research (Chairman).

Professor Deborah Sweeney, CEO, Vision CRC Limited, Australia; President, International Association of Contact Lens Educators.

Ms Wendy Ho, Private Practitioner, Australia.

Ms Jyoti Dave, Private Practitioner, India; Managing Trustee, Jyoticare Benevolent Foundation

Professor Xiao Mei Qu, EENT Hospital, Fundan University, China; Co-ordinator of International Association of Contact Lens Educators.

Dr Stan Isaacs, Private Practitioner; President, Singapore Contact Lens Society.

Professor Jai Min Kim, Head of Ophthalmic Optics Department, Keon Yang University, Korea; Chairman, Korean Ophthalmic Optics Society.

Dr Usman Husin, Private Practitioner, Indonesia.

Dr Joseph Fung, Private Practitioner; President, Hong Kong Optometric Association.

Dr Kah Meng Chung, Private Practitioner; President, Association of Malaysian Optometrists.

Associate Professor Pauline Cho, School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China.

Dr Huey-Chuan Cheng, Director at the Department of Ophthalmology, Mackay Memorial Hospital, Taiwan.

Professor Pei-Ying Xie, Director of Peking University, Optometry and Ophthalmology Center; Director of Tianjin Eye Hospital Contact Lens Centre.

Mr Kevin Siew, Private Practitioner; President, Malaysian Association of Practicing Opticians.

Mr Alan Saks, Private Practitioner, New Zealand.

Dr Wilfred Tang: Singapore Polytechnic, Head of Singapore Polytechnic Optometry Centre.

Assistant Professor Hsi-Ming Yang, Ophthalmology, Catholic FuJen University, Taiwan.

CONCLUSION

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

Contact lenses are medical devices that come into close contact with human tissue and it is important that practitioners and industry take all steps necessary to optimise patients’ ocular health.

For industry, new product standards and communication in package instructions will help to improve outcomes.

Practitioners should be aware of the risk of corneal staining with silicone hydrogel lenses and ensure optimum combinations of lens and solution for their patients. They should also be aware that with silicone hydrogels, hydrogen peroxide is currently the only solution that avoids corneal staining.

Finally, while regional studies have shown that contact lens-related infections are very rare, proper lens care, which includes hygiene, wear and replacement schedules, is a key factor in ensuring the safety of these devices. It is clear that lens and lens case hygiene are inadequate in many wearers. Therefore, regular reviews and reinforcement of care procedures for contact lenses and lens care accessories are essential to protect patients. The Guidelines for the Safe and Effective Use of Contact Lenses provide a valuable resource, providing the latest recommended practice to ensure contact lens safety.

ACKNOWLEDGEMENTS

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

The contributions of the following people are gratefully acknowledged: Professor Fiona Stapleton, School of Optometry and Vision Science, University of New South Wales; and Nicole Carnt, Dr Vicki Evans, Daniel Tilia, Dr Mark Willcox and Dr Hua Zhu of the Institute for Eye Research, University of New South Wales.

SOURCES OF FUNDING AND CONFLICT OF INTEREST

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES

The Asia Pacific Contact Lens Summit and the Asia Pacific survey were sponsored by Advanced Medical Optics. The Institute for Eye Research receives royalties from the sale of certain contact lenses mentioned in this report. The Vision CRC is supported by the Cooperative Research Centres program of the Australian Federal Government.

REFERENCES

  1. Top of page
  2. Abstract
  3. ADVERSE EVENTS
  4. CONTACT LENS WEAR
  5. ARE INFLAMMATORY EVENTS ASSOCIATED WITH AN INCREASED RISK OF MK?
  6. CAUSES AND RISK FACTORS
  7. PATIENT BEHAVIOUR
  8. SOLUTIONS
  9. PATIENT EDUCATION
  10. ASIA PACIFIC CONTACT LENS CARE SUMMIT
  11. GUIDELINES FOR THE SAFE AND EFFECTIVE USE OF CONTACT LENSES
  12. CONCLUSION
  13. ACKNOWLEDGEMENTS
  14. SOURCES OF FUNDING AND CONFLICT OF INTEREST
  15. REFERENCES
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