SINGAPORE: Wearing crazy-coloured contact lenses may complete a look for Halloween, but eye care professionals warn that users should get them properly fitted.
The lack of proper fitting is the most common issue associated with novelty contact lenses, said Dr Lim Li, senior consultant with the Corneal and External Eye Disease Department at the Singapore National Eye Centre.
While these lenses are usually non-prescription, they may not fit the curvature of a user's cornea well. This can only be determined by an optometrist or ophthalmologist using an instrument called the keratometer.
"The wrong fit can cause problems such as eye redness and discomfort, corneal abrasions and allergic conjunctivitis. There is also an increased risk of infection associated with poor fitting contact lenses," Dr Lim explained.
Unlike prescription contact lenses, novelty contact lenses are not considered medical devices, according to the Health Sciences Authority.
Furthermore, novelty contact lenses can be bought easily from websites, online marketplaces and even makeshift stalls. They can go for as low as US$1.20 (S$1.60) a pair on Alibaba to more than S$100 a pair through e-stores such as Glasses Avenue Singapore and Lensmart Singapore.
Companies are not allowed to sell contact lenses online directly to consumers, unless it is done through qualified personnel, according to the Ministry of Health.
Many users around the world turn to online sources because they offer a wide range of contact lens designs but some end up paying a heavy price.
In the United Kingdom, for instance, it was reported that an 18-year-old girl tore her cornea when she removed one of her "cat-eye" contact lenses after a Halloween night-out in 2015.
"The lens was so dry that it had stuck to my eyeball and ripped the cornea completely out with it," Tia Goode told the Daily Mail earlier this month.
A cornea tear can lead to blurred vision, blindness, pain and sensitivity under bright lights, as well as muscle spasms around the eye. Fortunately for Goode, she did not lose her sight.
Such stories are not uncommon, often caused by users' callous attitude towards novelty contact lenses.
“Some of the cases we see, like patients sharing lenses with friends, wearing the same pair year after year well past the expiry date, and storing them in tap water, have devastating effects,” Dr Badrul Hussain, a consultant ophthalmic surgeon at Moorfields Eye Hospital in London told the BBC.
CASTING A LOCAL EYE ON SUCH DANGERS
In Singapore, Dr Lim said there is no data on such cases resulting from the use of novelty contact lenses.
"However, there were 31 cases of contact lens-related infective keratitis admitted to the Singapore General Hospital for treatment last year," she said.
Infective keratitis, or bacterial infection of the cornea, is the most serious complication and potentially sight threatening condition that can result from using soft or novelty contact lenses.
According to Dr Lim, novelty contact lenses, with their colour and design incorporated into them, usually have low oxygen permeability and may result in the lack of oxygen to the cornea if worn for long periods. Novelty lenses may also predispose wearers to allergic conjunctivitis with symptoms of itchiness and eye redness.
Fortunately, the incidence rate is low, ranging from two to 10 per 10,000 cases, said Dr Lim. And in case you're wondering why you shouldn't wear your lenses to sleep, your chances of developing infective keratitis increases significantly to about 20 to 25 per 10,000 when you do.
To be safe, buy contact lenses from approved practitioners as those sold online are not likely to be regulated. Dr Lim offered these safety guidelines for those who are keen to put on contact lenses, novelty or not:
- Have your contact lenses fitted by a registered lens care practitioner. Do not purchase contact lens online without prior fitting as contact lenses need to be fitted according to the shape and curvature of the cornea
- Follow lens care instructions, especially the cleaning and storage of lenses, properly
- Replace lenses on a regular basis
- Avoid wearing the lenses overnight
- Once you've removed the lenses, never re-insert them without disinfecting them
- Discontinue wear if you develop redness in your eyes
- Wash your hands before handling lenses
- Avoid swimming with the lenses