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Social and Behavioural Issues
-Health Risks Associated with Contact Lenses

In Canada, over 90% of prescriptions are for soft contact lenses. Soft contact lenses (SCLs) are made of malleable plastic polymers that conform to the shape of the cornea.  This prevents intrusion of foreign objects such as dust particles between the eye and lens, provides added comfort, and adheres to movement of the eye (such lenses are not dislodged with blinking or vigorous activity). However, SCLs tend to absorb moisture from the eye, protein and lipid deposits from tear film, microbes and chemicals from the environment.

Contact  lenses  could  be  used  for  a  variety  of  cosmetic  or  vision  correction  needs  (including myopia, presbyopia, bifocals, and astigmatism), and generally provide clear, crisp vision. Contact lenses are suitable for people of all ages and are often associated with increased vision-related quality of life, particularly with respect to limitations of activities, appearance, peer-perception, and personal satisfaction. Contact lenses are associated with a high level of social acceptance; wearing cosmetic/corrective lenses is generally perceived as low risk for the public.

Contact  lenses  may  cause  a  range of  mild  to  moderate  complications  such as dry  eye syndrome,  as  well  as  uncommon  but  more severe  effects  such as microbial  and corneal ulcers. The majority of these adverse health effects is avoidable with compliance with manufacturer-recommended replacement schedules, wear times, and cleaning, better personal hygiene and lens care practices, and reduced high- risk behaviors such as smoking, swimming with lenses, and wearing lenses in dangerous environments.

The use of soft contact lenses is associated with several potential health risk issues.

  1. SCLs are prone to microbial contamination. Bacteria, fungi, and parasites thrive on contact lenses,  storage  cases,  and  eyelids  (inner  and  outer)  even  in asymptomatic  users.  Large microbial burdens can result in mild to very severe corneal infections (microbial keratitis) that can cause vision loss and/or blindness. Corneal infiltrates (irritation/scaring) occur in 7-25% of contact lens wearers as a result of corneal infection and inflammation.
  2. SCLs are also prone to protein/lipid   buildup.  Tear  film  proteins   (lysozyme,   albumin, lactoferrin) and lipids (cholesterol esters) are adsorbed onto the contact lens surface in as little as 15 minutes and increase with continuous wear. Buildup of proteins and lipids, without proper cleaning, can cause corneal abrasions, irritation, redness, and dry eyes. Dry eye syndrome is the most common complication and occurs in over 50% of contact lens wearers.
  3. Poor  personal  hygiene  and  low  compliance  with  replacement  schedules  and  cleaning regimes increase the risk of adverse health effects. In Canada, 38% of contact lens wearers are not compliant with manufacturer-recommended replacement schedules. Furthermore, many users report high-risk behaviors such as napping with lenses (75%), overnight wear of lenses (28%), and cleaning their lenses or storage cases with tap water (72%).
  4. Lens cleaning solutions, especially those containing hydrogen peroxide, can cause eye irritation and damage if not used according to the manufacturer instructions. Multipurpose solutions and hydrogen peroxide solutions can significantly reduce microbial burden, but are only effective if used according to manufacturers’ instructions. Storage case solutions should never be left open because disinfectants can evaporate or neutralize over time. Solutions should also be kept in their original packaging to ensure sterility.
  5. Sensitive populations may be at increased risk of developing adverse effects. These include women (majority of lens wearers), smokers (susceptible to ulcers), persons with specific occupations (unsafe environment for eyes), persons with preexisting medical conditions (viral infections, diabetes, eye diseases), and individuals taking medications that increase dryness of the eyes (antihistamines, birth control).
  6. Contact lenses should be fitted by trained practitioners to maintain good eye health. Cosmetic  (non-prescription) contact  lenses  are  associated  with  a  12  times  greater  risk  of  infection  compared  to prescription lenses.


In Canada, corrective contact lenses are regulated under the Food and Drug Act as medical devices,  which  are  defined  as  products  used  in  the  treatment,  mitigation,  diagnosis  or prevention of a disease or abnormal physical condition. All prescription lenses require licensing from Health Canada before sale or distribution. Non-prescription cosmetic/decorative contact lenses, on the other hand, are regulated as consumer products and do not require licensing. However, due to the high frequency of adverse health effects associated with cosmetic lenses, Health Canada amended the Food and Drug Act and Regulations to include cosmetic non-prescription lenses as class II medical devices under Bill C-313, which will take effect on July 16, 2016.

Health Canada has also established industry guidelines for contact lens cleaning solutions sold and imported in Canada as well as packaging and labeling guidelines for contact lens manufacturers and distributors. All multipurpose and hydrogen peroxide solutions must meet minimum disinfecting standards and contain safe level of chemicals, disinfectants, and other additives.  As a result  of several  incidences  of corneal  chemical  burns  from improper  use  of  hydrogen  peroxide  disinfecting  solutions,  Health  Canada  has  recently requested  that  manufactures  update  the  labels  on  their  product  packaging  in  order  to highlight the risk of improper use and provide the consumer with clearer, step-by-step instructions  for  use.  In the United States, the Food and Drug Administration   provides similar regulations and guidelines for contact lens and contact lens cleaning solution manufactures.

There is also Canadian legislation at the federal, provincial and territorial levels regarding the use of contact lenses in specific work environments. In general, it is advised that individuals avoid wearing contact lenses in environments  that  include  (a) exposure  to chemical  fumes  and  vapors,  (b) areas  where potential  for  chemical  splash  exist,  (c)  areas  where  particulate  matter  or  dust  is  in  the atmosphere, (d) exposure to extremes of infrared rays, (e) intense heat, (f) dry atmosphere, (g) flying particles, and (h) areas where caustic substances are handled, particularly those under pressure.

Future risk management strategies should be aimed at increasing public awareness and consumer education. New training and education programs  can  promote  dialog  among contact  lens  users  and  eye  care  specialists  in order  to increase  compliance  with  proper contact lens care. Emphasis should be placed on how to clean contact lenses, maintain hygienic practices, and avoid unnecessary high-risk behaviors (napping/sleeping with lenses, using water to clean cases/lenses, swimming with lenses on, and smoking) In addition, school- based   programs,   community/counseling programs, advertisements, and public events (shows, conferences, and symposia) should include educational initiatives to enhance self- acceptance and positive body image.


Useful Links

Health Canada - Healthy Living

U.S. Food and Drug Administration - Contact Lenses

Centres for Disease Control and Prevention - Healthy Contact Lens Wear and Care

Canadian Ophthalmological Society - Cosmetic Halloween Lenses lenses-mask-serious-eye-injuries-2/

Canadian Ophthalmological Society - Bill C-313 for Non-Corrective Contact Lenses

Health Canada - Recalls and Alerts on Hydrogen Peroxide Solutions

Canadian Centre for Occupational Health and Safety - Contact Lenses at Work


Further Reading

Szczotka-Flynn, L., et al., 1. History, evolution, and evolving standards of contact lens care.Contact Lens and Anterior Eye, 2013. 36: p. S4-S8.

Kathryn Dumbleton, D.R., Craig Woods, Lyndon Jones, and Desmond Fonn, Compliance with Contact Lens Replacement in Canada and the United States. Optometry and Vision Science,2010. 87(2): p. 9.

Wu, Y., N. Carnt, and F. Stapleton, Contact lens user profile, attitudes and level of compliance to lens care. Contact lens & anterior eye : the journal of the British Contact Lens Association,2010. 33(4): p. 183-8.

Luensmann, D. and L. Jones, Protein deposition on contact lenses: the past, the present, and the future. Contact lens & anterior eye : the journal of the British Contact Lens Association,2012. 35(2): p. 53-64.

Jiang, Y., et al., Risk factors for microbial bioburden during daily wear of silicone hydrogel contact lenses. Eye & contact lens, 2014. 40(3): p. 148-56.

Mela, E.K., et al., Fungal isolation from disinfectant solutions of contact lens storage cases among asymptomatic users. Eye & contact lens, 2015. 41(2): p. 87-90.
Mascarenhas, J., et al., Acanthamoeba, fungal, and bacterial keratitis: a comparison of risk factors and clinical features. American journal of ophthalmology, 2014. 157(1): p. 56-62.
Siddiqui, R., S. Lakhundi, and N.A. Khan, Status of the effectiveness of contact lens solutions against keratitis-causing pathogens. Contact lens & anterior eye : the journal of the British Contact Lens Association, 2015. 38(1): p. 34-8.

Lisa Keay, K.E., and Fiona Stapleton, Signs, Symptoms, and Comorbidities in Contact Lens- Related Microbial Keratitis. Optometry and Vision Science, 2009. 86(7): p. 7.

Szczotka-Flynn, L. and R. Chalmers, Incidence and epidemiologic associations of corneal infiltrates with silicone hydrogel contact lenses. Eye & contact lens, 2013. 39(1): p. 49-52.


Contributor:             Andreea Mihaela Slatculescu

Last Reviewed:       October 22, 2015


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