Summary Safety Review - Intraocular lenses - Assessing the potential risk of developing small pockets of liquid in intraocular lenses (glistening)
July 26, 2017
Potential Safety Issue
Development of glistening
- An intraocular lens (IOL) is a medical device licensed for sale in Canada to replace a cloudy lens in the eye of a cataract patient. Glistening is when very small pockets of liquid collect inside the IOL, which may change the quality of a person's vision by increasing glare and/or making things blurry.
- As part of Health Canada's ongoing monitoring of glistening development in IOLs, Health Canada reviewed the available safety information about how and why glistening develops, and if glistening changes the quality of a person's vision.
- Overall, Health Canada's review found that the available evidence is not strong enough to determine how or why glistening develops, or if glistening changes the quality of a person's vision. Health Canada will continue to monitor the safety of IOLs and will take appropriate action, if and when new information becomes available.
As part of Health Canada's ongoing monitoring of glistening development in IOLs, Health Canada reviewed the available safety information related to this issue. Health Canada has been actively monitoring reports of IOL glistening since 2012, with additional safety reviews completed in May 2015 and the current review. The findings from Health Canada's 2012 review were published in Health Canada's Canadian Adverse Reaction Newsletter (CARN) to raise awareness about this potential side effect and to encourage reporting of glistening associated with IOLs.
Use in Canada
- An intraocular lens (IOL) is a medical device licensed for sale in Canada to replace a cloudy lens in a cataract patient's eye.
- A cataract is a cloudiness in the normally clear lens of the eye. The cloudiness can decrease the quality of a person's vision, and may lead to blindness unless the lens is replaced.
Safety Review Findings
- When the current review was started, Health Canada had received a total of 180 reports of the development of glistening in people with IOLs, of which 26 were reported to Health Canada between May 2015 and December 2015. From January to August 2016, Health Canada received 1 report of glistening in IOLs.
- Many of the Canadian reports of glistening also noted that there was a change in the quality of a person's vision, by increasing glare and/or making things blurry. This possible association could not be confirmed because the lenses were not returned to the manufacturer for more testing.
- There was not enough detailed information in the reports received by Health Canada to confirm if the glistening was responsible for the changes in the person's vision, or if the changes were due to a different eye problem, or if there were any follow-up actions taken (for example, whether the IOL was replaced).
- In the literature, there are reports of glistening development in IOLs associated with different types of IOLs made by different manufacturers. So far, all of the glistening reports received by Health Canada have been for IOLs made by a single manufacturer, Alcon Laboratories. In 2012, Alcon Laboratories introduced changes to how their IOLs are made in order to decrease the likelihood of glistening development.
- In the literature, some studies have found links between glistening and a change in the quality of a person's vision while others have not. There are many factors that can affect the risk of glistening development including: what the IOL is made of, how the IOL is made, how the IOL is packaged and changes in IOL temperature. Further studies are needed to find out how or why glistening develops in IOLs and its potential effect on the quality of a person's vision.
Conclusions and Actions
- Overall, Health Canada's review found that the available evidence is not strong enough to determine how or why glistening develops, and if it changes the quality of a person's vision.
- Health Canada encourages consumers and healthcare professionals to report any cases of glistening development in IOLs.
- Furthermore, in patients who have developed glistening in their IOL(s), if the lens is surgically removed, doctors should return the defective devices to the manufacturer for further study.
- Health Canada will continue to monitor safety information involving IOLs, as it does for all medical devices on the Canadian market, to identify and assess potential harms. Health Canada will take appropriate and timely action if and when any new health risks are identified.
The analysis that contributed to this safety review included scientific and medical literature, Canadian and international safety information and what is known about the use of these devices both in Canada and internationally.
For additional information, contact the Marketed Health Products Directorate.
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