The 9 things to know about safely using contact lens cases
Most contact lens users are aware that cleaning and disinfecting their lenses properly is extremely important. However some of us tend to forget that a clean lens case is also essential for healthy and safe contact lens wear. A number of studies have demonstrated this quite clearly.
The first one was performed by a team of young researchers led by Dr Shannon McQuaig. They tested how clean lens cases really are by collecting used cases from a number of patients, who were also interviewed about how often they replaced them.
According to Dr McQuaig, most patients participating in the study were not sure when they started to use their cases.
The tests the team carried out consisted of allowing the microbes found in the cases to grow and then counting them. The results were shocking with some samples containing dangerous bacteria with populations in the tens of thousands. In addition the researchers found that there was a positive relationship between the period of time a case was used and the number of bacteria growing inside it.
Dr McQuaig concluded that patients need to replace their lens cases much more often and avoid reusing lens care solutions.
Another study (1) was meant to assess the contamination of contact lens accessories and the levels of compliance with procedures regarding lens case cleaning as well as their impact on contamination levels.
The researchers collected almost 50 contact lens cases and solutions from patients not showing any symptoms of contact lens complications. They cultured samples from the cases and solutions, and provided the subjects with special questionnaires concerning their attitude towards care and hygiene procedures.
It turned out that 50% of the cases and almost 11% of the solutions were contaminated with bacteria, mostly Staphylococcus aureus and Eschericia coli. Cases used for less than 3 months were found to be significantly less often contaminated than those used for more than 3 months. In addition, the cases of patients whose levels of compliance were low or medium were significantly more frequently contaminated than the cases of patients with high levels of compliance.
The researchers concluded that contact lens wearers from the tested region were at high risk of eye infections and other lens-related complications resulting from lens case contamination. They recommended more frequent replacement of lens cases and better compliance with hygiene procedures.
The third study (2) was lead by Dr Mark Willcox and his team from the University of New South Wales and published in Optometry and Vision Science. It has revealed that the contact lens cases of patients who do not follow the recommended hygiene procedures are often contaminated with dangerous bacteria.
The researchers included almost 120 contact lens users in their study. The subjects were asked to fill in a special questionnaire concerning their habits related to contact lens hygiene and to provide their used contact lens cases. The cases were examined in a laboratory to check if they were contaminated. Then the researchers analysed the obtained data to establish whether there was a relationship between contact lens hygiene and lens case contamination. The authors of the study were able to determine three factors contributing to lens case contamination: failure to wash hands before touching contact lenses, failure to air-dry cases and the use of cases and disinfecting solutions produced by different companies. Additionally, contact lens cases provided by experienced lens wearers tended to be more contaminated, the researchers write in their report.
The key steps to preventing bacterial contamination, the authors of the study emphasised, are washing hands thoroughly with water and soap, air-drying lens cases and using disinfecting solutions and lens cases produced by the same manufacturer.
TL;DR
To sum up findings from the above mentioned studies, there seems to be an established correlation between level of contact lens case hygiene and the risk of lens contamination and potential eye infection with dangerous microbes. There is also a link between the number of bacteria found and the length of time the case has been in use. So we recommend that you change your case and solution on a monthly basis. Additionally in order to keep your contact lenses clean and safe, you should follow these 9 steps to safely use contact lens cases:
- always wash your hands with soap and warm water before handling contact lenses and lens cases
- thoroughly clean your contact lens case with cleaning solution every time you use your contact lenses
- if possible, use lens cases manufactured by the same maker as your lens solution.
- never reuse lens solution - discard the old batch before filling the new lens case with the new solution
- replace your lens case regularly - once every month is recommended. Older than 3 months is very risky.
- keep your contact lens cleaning solution and case in a cool, dry place and out of direct sun light
- never touch the end of your contact lens solution bottle so as not to contaminate the liquid inside
- never use an expired lens cleaning solution
- never mix different solutions in one case
If you follow these guidelines, your lens case should remain clean and safe during use and until you discard it. This will help to reduce the risk of lens contamination to a significantly low level. Remember your hygiene is the most important factor in preventing potentially dangerous eye infections. Your eye sight is important so look after it well and avoid infection.
Sources:
(1) https://www.contactlensjournal.com/article/S1367-0484(13)00085-4/fulltext
(2) https://journals.lww.com/optvissci/Abstract/2015/02000/The_Effect_of_Contact_Lens_Hygiene_Behavior_on.9.aspx
