These notes have been prepared by Dr Hainey, daysoft limited, for those who want to read the technical papers on why daily-disposable contact lenses are the best for your eyes.

An unprecedented number of recalls for contact lens solutions occurred in 2006; Alcon's Systane Free Liquid Gel, Advanced Medical Optic's Complete MoisturePlus multipurpose contact lens solution, Bausch &Lomb's ReNu MoistureLoc multipurpose solution and ReNu MultiPlus multipurpose solution. Whilst, the exact reasons for the need to recall are still the subject of debate, infestation by microbes was a common problem to all of them.

In the most recent assessment of current contact lens (CL) compliance, Morgan [1] showed that nearly all wearers who change their lenses after planned intervals (known as scheduled replacement) do not completely follow recommended lens cleaning and care steps, which is in agreement with earlier studies [2, 3], and that this behaviour is associated with at least a doubling of the risk of keratitis (when the eye's cornea becomes inflamed). The risks that come from not following these procedures should be considered along with the highlighted problems of microbial infestation present in 80% of contact lens cases [4, 5], and the evidence that a variety of infectious microbes can attach and grow into contact lenses within 3 days [6 - 8]. As well as these points, other recent studies have concluded that complications with contact lens use, such as Acanthamoeba keratitis (AK) [9] and corneal ulcers [10] are increasing in relative frequency amongst wearers.

Efron [11] investigated the disinfecting ability of several multipurpose solutions (MPS) using different cleaning methods against known pathogenic strains of a variety of microbes. The results of the study showed that using similar cleaning procedures with different MPS can show very different disinfection abilities. This shows that a wearer can be placed at adverse risk simply by switching MPS. Also, the use of MPS has been implicated in contact-lens related dry eye and other sensitisation issues [12-15], with polyhexamethylene biguanide (referred to as PHMB) regarded as the main culprit. When the current controversy over corneal staining for combinations of silicone hydrogels and MPS containing PHMB [16] is also taken into account, it can be seen that there are serious concerns regarding the overall suitability of MPS [31].

It has also been shown that the build-up of a layer of microbes held together by a glue-like material, known as a biofilm, in contact lens cases can protect microbes from even one-step peroxide disinfection systems [4, 5, 31], and that the presence and amount of biofilm did not directly relate to non-compliance with cleaning and disinfection procedures [5]. This implied that following recommended hygiene practise does not guarantee contamination-free contact lenses and storage cases ! It was also found that many cases were contaminated with different microbes, such as bacteria and fungi or protozoa, all at the same time.

The daily disposable (DD) contact lens with its intentional single use application has been shown by numerous studies to be the safest way to wear lenses [17-30] . Amongst the particular advantages shown for the daily disposable lens wear are that it is;

  • the most effective for compliance (up to 98% [17, 18])
  • the lowest rate of complications from wear [19 - 25]
  • beneficial to wearers with allergies or dryness [26]
  • the most effective mode for avoiding giant papillary conjuctivitis (GPC) / contact lens induced papillary conjunctivitis (CLPC) [27, 28]
  • up to 8 times safer than sleeping with lenses in, as during extended wear (EW) or continuous wear (CW) [24, 28 - 30]

The basis of daily disposable wear, where a lens is placed in the eye directly from a sterile container and, that the lens is removed from the eye and discarded after wearing, ensures that no biofilm build-up or solution intolerance can occur. The constant supply and ease of use of daily disposable lenses should remove the need or incentive to wear lenses during sleep. This leads to the greatly reduced rate of complication seen with daily disposable contact lens wear.


References:

  1. Morgan, P., 'Contact lens compliance and reducing the risk of keratitis', Optician, 2007, 234: 6109, 20-25, http://opticianonline.net
  2. Sokol J. L. et al; 'A study of patient compliance in a contact lens wearing population.' CLAO J, 1990; 16(3): 209-13
  3. Sulley A., 'Compliance in contact lens wear – part 1' Optician, 2005; 229(5995): 24-30, http://opticianonline.net
  4. Gray T. B., Cursons R. T. M., Sherwan J. F., Rose P. R.; 'Acanthamoeba, bacterial, and fungal contamination of lens storage cases', Br. J. Ophthalmol. , 1995; 79: 601-605.
  5. McLaughlin-Borlace L., Stapleton F., Matheson M., Dart J. K.; 'Bacterial biofilm on contact lenses and lens storage cases in wearers with microbial keratitis', J. Appl. Microbiol., 1998; 84: 8, 27-38.
  6. Giese, M. J., Weissman, B. A.; 'In vitro Colonisation of hydrophilic contact lenses by Aspergillus niger', J. Ind. Microbiol. Biotechnol., (2002) 29, 6-9
  7. Marqués-Calvo M. S., 'Colonisation of hydrophilic contact lenses by yeast'', J Ind Microbiol Biotechnol (2004) 31: 255–260
  8. Marqués-Calvo M. S., 'Bacterial colonization of rigid gas permeable and hydrogel contact lenses by Staphylococcus aureus', J. Ind. Microbiol. Biotechnol., (2000) 24, 113–115
  9. Joslin et al, 'Epidemiological characteristics of a Chicago-area Acanthamoeba keratitis outbreak', Am. J. Ophthalmol., 2006, 142: 2, 212-7.
  10. Verhelst D., Koppen C., Van Looveren J. et al; 'Contact lens-related corneal ulcers requiring hospitalization: A seven-year retrospective study in Belgium', Acta. Ophthalmol. Scand., 2006: 84: 4, 522-6.
  11. Efron,N. Morgan,P.B. Hill,E.A. Raynor,M.K. Tullo,A.B.; ' Anatomy of a regimen: consideration of multipurpose solutions during non-compliant use', CLAE 26 (2003); 17-26
  12. Smythe, J. L., 'Managing Solution-Related Dryness', Contact Lens Spectrum, March 2003, www.clspectrum.com
  13. André, M., 'Contact Lens Care Products: Problem or Solution', Contact Lens Spectrum, July 2004, www.clspectrum.com
  14. Nichols, J. J., 'Preservative-Related Dryness ?', Contact Lens Spectrum, May 2006, www.clspectrum.com
  15. Caroline, P. J., 'Guilty Until Proven Innocent', Contact Lens Spectrum, May 2007, www.clspectrum.com
  16. Andrasko, G. J., www.staininggrid.com
  17. Kame et al; 'Are Your Patients Ready for Daily Disposables ?', Spectrum, 1994; 9: 26-31
  18. Hamano H., Watanabe K., Hamano T., Mitsunaga S., Kotani S., Okada A.; 'A study of the complications induced by conventional and disposable contact lenses.' CLAO J 1994; 20(2): 103-108
  19. Nilsson S. E. G., Söderqvist M.; 'Clinical performance of a daily disposable contact lens: a 3 month prospective study', J. BCLA 1995; 18(3): 81-86
  20. Solomon O. D. et al; 'A 3-year prospective study of the clinical performance of daily disposable contact lenses compared with frequent replacement and conventional daily wear contact lenses.' CLAO J 1996; 22(4): 250-257
  21. Suchecki J. K., Ehlers W. H. , Donshik P. C; 'A comparison of contact lens related complications in various daily wear modalities.' CLAO J 2000; 26(4): 204-213
  22. Sankaridurg P. R. et al; 'Comparison of adverse events with daily disposable hydrogels and spectacle wear.' Ophthalmology 2003; 110(12): 2327-2334
  23. Schnider C. M., Veys J., Meyler J.; 'The use of 1-day Acuvue in patients reporting dry, sensitive or easily irritated eyes.' Optician, 2004; 227(5937): 20-22, http://opticianonline.net
  24. Morgan P. B., Efron N., Hill E. A., Raynor M. K., Whiting M. A., Tullo A. B.; 'Incidence of keratitis of varying severity among contact lens wearers.', Br. J. Ophthalmol., 2005; 89: 430-436
  25. Veys J. and French K.; 'Health benefits of daily disposable contact lenses.' Optician, 2006; 231: 6050, 16-20, http://opticianonline.net
  26. Hayes V. Y., Schnider C. M., Veys J.; 'An evaluation of 1 day disposable contact lens wear in a population of allergy sufferers.'; CLAE 2003; 26: 85-93
  27. Porazinski A. D., Donshik P. C.; 'Giant papillary conjunctivitis in frequent replacement contact lens wearers: a retrospective study.' CLAO J 1999; 25(3): 142-147
  28. Skotnitsky, C.; Sankaridurg, P. R.; Sweeney, D. F.; Holden, B. A.; ' General and local contact lens induced papillary conjunctivitis (CLPC)', Clin Exp Optom, 2002; 85: 3: 193–197, http://www.optometrists.asn.au/ceo
  29. Schultz C. L., Kunert K. S., White R.; 'Contact lens associated corneal infections. Where do we go from here?' Clin Exp Optom, 2002; 85: 3:141-148, http://www.optometrists.asn.au/ceo
  30. Rosenthal et al; ' Incidence and morbidity of hospital-presenting corneal infiltrative events associated with contact lens wear', Clin Exp Optom, 2005; 88: 4: 232–239, http://www.optometrists.asn.au/ceo

'New study finds resistant organisms at core of soft contact lens corneal infections', Public Release: 28-Jan-2008, National Institutes of Health, http://www.eurekalert.org/pubnews.php, Optometry Today, http://www.optometry.co.uk; 'Contact Lens Care Solutions Inadequately Tested With Outdated And Irrelevant Fungus Strain', Medical News Today, http://www.medicalnewstoday.com/articles/95417.php