Featured Research

from universities, journals, and other organizations

Optometrists raise alert on potential risk of colored contact lenses

Date:
October 29, 2013
Source:
The Hong Kong Polytechnic University
Summary:
Researchers have recently conducted a study on 15 brands of colored contact lenses available from various sources. Results showed that most of these cosmetic contact lenses have surface colored pigments which can easily come off when using a standardized lab-based rub-off test.

Researchers of The Hong Kong Polytechnic University (PolyU)'s School of Optometry (SO) have recently conducted a study on 15 brands of coloured contact lenses available from various sources including Internet, cabinet stores and optical shops. Results showed that most of these cosmetic contact lenses have surface coloured pigments which can easily come off when using a standardised lab-based rub-off test.

Related Articles


When exposed to micro-organisms, lenses with surface pigments have significantly more attachment of microorganisms. Users purchasing coloured contact lenses casually from unauthorised or street vendors without a prescription are exposing themselves to a high risk of contact lens-associated complications. "All contact lenses, coloured or otherwise, should be prescribed by registered contact lens practitioners after proper eye examination and lens fitting, and with proper advice and aftercare," said Professor Pauline Cho of PolyU SO

In Hong Kong, coloured contact lenses have become trendy fashion accessories. Many people wear these lenses at parties and on festivals such as Halloween and Christmas. As there is no regulation that restricts the sales of contact lenses in Hong Kong, the public can easily purchase these lenses via internet sellers, retailers or consignment counters. However, information about the countries of origin, materials, pigments used, and manufacturing processes of these contact lenses are not readily available. Improper use of these contact lenses will impose risks to the users' ocular health.

Professor Pauline Cho, Professor of SO, led her research team in this study on 15 brands of coloured contact lenses available in the market. "This is the first ever study in the world comparing the levels of microbial adhesion to coloured contact lenses which have surface, embedded or sandwiched pigments. All other published reports on microbial adhesion only focussed on clear hydrogel and silicone hydrogel lenses," said Professor Cho.

In this study, Professor Cho and her team conducted two experiments on coloured contact lenses. The first experiment was to compare the level of microbial adhesion among 15 brands of coloured contact lenses. As materials and water content levels of the contact lenses can affect the level of microbial adherence, the second experiment compared three brands of coloured contact lenses with their clear counterparts (i.e. clear contact lenses with the same material and water content).

A total of 15 brands of coloured contact lenses (5 lenses per brand), purchased from optical shops, consignment counters and internet sellers were tested. All lenses, except those of 2 brands, failed the standardised rub-off test (i.e. pigments came off in the rub-off test), indicating that the coloured pigments were neither embedded nor sandwiched in the contact lenses. When challenged with micro-organisms (new sets of lenses, 5 lenses per brand), the levels of microbial adherence to the lenses of the 13 brands of contact lenses which failed the rub-off test were at least six times higher than the lenses of the other two brands which passed the test.

Results of the second experiment showed that coloured contact lenses which failed the rub-off test have higher levels of microbial adherences when compared to their clear counterparts. Coloured contact lenses which passed the rub-off tests (pigments embedded or sandwiched) showed no significant difference in microbial adhesion when compared to their clear counterparts. These results confirmed that surface pigment on coloured contact lenses which were not employing embedded or sandwiched design, was most likely to be the factor leading to higher microbial adherence in these lenses.

Professor Cho reminded consumers that consultation with their contact lens practitioners before wearing contact lenses is of paramount importance. "Coloured contact lenses are increasing in popularity as fashion accessories. However, it is important that they are prescribed by professional contact lens practitioners, not only to ensure the quality and reliability of the contact lenses, but also to ensure proper eye examination, fitting and instructions on usage and care, and regular check-ups to minimize complications that can be associated with contact lens wear. Consumers are therefore reminded not to patronise hawkers, consignment counters or internet sellers," said Professor Cho.

"This is not to say that coloured contact lenses with surface pigments are not safe but that lenses with surface pigments allow more adhesion of microorganisms. It is therefore very important that such lenses should be cared for appropriately or discarded accordingly according to the modality," said Professor Cho.

Halloween is coming soon and Professor Cho foresees that quite a number of non-regular contact lenses users will attempt to wear coloured contact lenses at this time. "These users will have higher risks of eye infections if they do not have adequate knowledge on proper usage and handling of the contact lenses or if they exchange or borrow lenses from other users. Again, consumers are reminded that any contact lenses, if not used and/or cared for properly will not be safe. They should consult a professional contact lens practitioner. Be smart and protect the 'windows to the soul'," said Professor Cho.


Story Source:

The above story is based on materials provided by The Hong Kong Polytechnic University. Note: Materials may be edited for content and length.


Cite This Page:

The Hong Kong Polytechnic University. "Optometrists raise alert on potential risk of colored contact lenses." ScienceDaily. ScienceDaily, 29 October 2013. <www.sciencedaily.com/releases/2013/10/131029104328.htm>.
The Hong Kong Polytechnic University. (2013, October 29). Optometrists raise alert on potential risk of colored contact lenses. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2013/10/131029104328.htm
The Hong Kong Polytechnic University. "Optometrists raise alert on potential risk of colored contact lenses." ScienceDaily. www.sciencedaily.com/releases/2013/10/131029104328.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rural India's Low-Cost Sanitary Pad Revolution

Rural India's Low-Cost Sanitary Pad Revolution

AFP (Nov. 28, 2014) — One man hopes his invention -– a machine that produces cheap sanitary pads –- will help empower Indian women. Duration: 01:51 Video provided by AFP
Powered by NewsLook.com
Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) — In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
WHO Says Male Ebola Survivors Should Abstain From Sex

WHO Says Male Ebola Survivors Should Abstain From Sex

Newsy (Nov. 28, 2014) — WHO cites four studies that say Ebola can still be detected in semen up to 82 days after the onset of symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins