Coloured, corrective contact lenses a concern

Each day, more than one contact lens wearer here ends up with a corneal infection. Most cases are mild but some are so bad that a transplant is needed.
By Salma Khalik, Senior Health Correspondent, The Sunday Times, 4 Jan 2015

Each day, more than one contact lens wearer here ends up with a corneal infection. Most cases are mild but some are so bad that a transplant is needed.

In 2013, the public sector alone treated a total of 531 corneal infections, of which 362 were contact lens related, and hence avoidable, said Professor Donald Tan, a senior ophthalmologist at the Singapore National Eye Centre (SNEC).

It is not known how many corneal infections are treated in the private sector.

Coloured lenses are especially a concern, as they accounted for 92 infections here in 2013.

Prof Tan said eye doctors at the SNEC hear all kinds of horror stories: poor-quality lenses bought over the Internet where there is little quality control, dye leaking out of the lens into the eye, and children who swop lenses they have been wearing to try a different colour.

As coloured lenses are not medical devices but cosmetic, there is little control over their quality.

A Singapore-led year-long study conducted from end 2012 till early last year across eight Asian territories looked at a total of more than 6,500 eye infections.

Among them, Singapore had the most corneal infections caused by lens wear at 68 per cent, followed by Taiwan where the figure is around half that.

According to industry numbers, about 200,000 people here wear contact lenses.

Besides coloured lenses, also of concern to doctors are the hard lenses worn overnight by the young to reshape the cornea so that they do not need to wear spectacles or lenses in the day.

Prof Tan, who specialises in cornea and external eye diseases, said public sector health institutions treated five infections in 2013 caused by the use of such hard corrective lenses called Ortho-K.

Last year, the SNEC alone saw three cases of eye infection caused by use of these lenses, which are used to correct short-sightedness.

Prof Tan said these lenses - in order to reshape the eyeball - "squash the cornea, causing little breaks on the surface so wearers are more prone to infections".

Wearers of Ortho-K lenses are 13 times more likely to get an eye infection than an adult wearing ordinary hard lenses in the day, he said.

The eye centre has been seeing Ortho-K infections in young children since 2001. One problem, said Prof Tan, is that eye hygiene might be poorer in children, who are the target of Ortho-K corrective lenses.

Another possible reason is that the lenses are worn overnight, when the eyes are closed, so less oxygen gets through.

For these children, instead of getting better eyesight, they often end up with a 10 per cent to 40 per cent vision loss instead.

Infections caused by Ortho-K lenses tend to be more severe and might lead to permanent scars in the eye which would affect vision, said Prof Tan.

These have led to eye transplants in other countries, but not in Singapore so far, he said.

INFECTION LIKE 'ULCER IN THE EYE'
By Salma Khalik, The Sunday Times, 4 Jan 2015

The three victims of Ortho-K corneal infections who were seen at the Singapore National Eye Centre last year were aged 10, 14 and 17.

In the worst case, the 14-year-old boy has such a bad infection that he could lose most of his sight in his left eye.

His eye has been infected with the acanthamoeba bug, which is one of the most painful eye infections, said Professor Donald Tan, a senior consultant at the centre.

To treat it, doctors have to use a blade to scrape the surface of his eye to remove the amoeba and to clean out any "debris" such as pus and dead cells.

The infection is like having an ulcer in the eye, Prof Tan said.

The boy, whose parents did not want him to be identified, had to put five types of eye drops into the raw wound in the eye every half an hour round-the-clock for four days.

To be effective in killing the organism, the eye drops have to be quite toxic, said Prof Tan, hence the severe pain.

This meant no sleep at all for three nights for the boy or his worried parents.

The number of eye drops and frequency of application have been reduced now, but he will miss the first six weeks of school to allow the eye to heal.

He has to continue using these special eye drops to prevent another infection in the eye, as a third of it is still an open wound.

All he can see out of that eye now are the big letters in the top line of an eye chart, but Prof Tan hopes he will eventually recover half his vision in that eye.

The boy's father said that he would wake them up at night when the pain is excruciating.

His mother said that the usually stoic boy would cry out in pain. "One night when the pain was so bad, he asked me to pray for him," she said.

One of her worst fears was how he would accept losing part of his sight, as he is such an avid volleyball player.

The pain is caused by the bugs nibbling the nerve ends in the eye, said Prof Tan.

The boy started wearing Ortho-K lenses in Primary 2, and had myopia of 600 degrees. His parents put him and his two siblings on the Ortho-K lenses in the hope that it would slow down the development of their myopia.

They said it seemed to have worked, but they were now "devastated" because of the suffering their son is going through.

His father said: "The hardest part is not knowing when or how well it would heal."

Safe to wear contact lenses, if proper care is taken

Contact lenses per se do not cause eye infections ("Coloured, corrective contact lenses a concern"; last Sunday).

Infections may be due to improper hygiene, non-compliance with the cleaning regimen, or lack of follow-up care. Infective organisms such as acanthamoeba are typically found in contaminated water.

If coloured contact lenses from non-reliable sources are a major cause of contact lens-related eye infections, then it would be prudent for the authorities such as the Health Sciences Authority to prohibit their sales on the Internet, or from any sources that bypass the opportunity for eye exams by an optometrist.

Contact lens industry sources estimate that there are 600,000 contact lens wearers in Singapore, and not 200,000 as previously stated.

This puts the incidence of contact lens-related infections at 0.06 per cent. This shows that, with appropriate measures in place, wearing contact lenses is safe and can be made safer.

The process of corneal reshaping with orthokeratology (Ortho-K) lenses is not a simplistic "squashing" of the cornea or "causing little breaks on the surface", but rather a gradual reshaping process due to the forces of the tear film under the lens. A properly fitted orthokeratology lens does not contact the cornea but sits on the tear film. At no time is the corneal surface meant to be broken.

Studies show that orthokeratology lenses are no riskier than other types of contact lenses worn overnight. However, one has to consider the merits of orthokeratology, that is, control of myopic progression.

High myopia is a potentially blinding condition. While there are other options, there is none that is risk-free. With orthokeratology, the benefits outweigh the risks.

I hope that with the involvement of the optometric community in this dialogue, the public will have a balanced view of the issue of contact lens use, and be mindful of the need for compliance.

Koh Liang Hwee (Dr)
President
Singapore Optometric Association
ST Forum, 11 Jan 2015

Regulatory measures for ensuring safe use of contact lenses

We are encouraged by letters highlighting the important role that consumers play in safeguarding their eye health when using contact lenses ("Safe to wear contact lenses, if proper care is taken" by Singapore Optometric Association president Koh Liang Hwee and "Best to go for regular eye checks" by Mr Yap Tiong Peng; last Sunday).

Consumers should undergo proper eye examination and contact lens fitting by registered optometrists or contact lens practice opticians. They should not buy contact lenses from unlicensed vendors over the Internet or from other dubious sources, as they are often counterfeit or substandard.

Using such illegal products may have adverse consequences like conjunctivitis, and corneal abrasions and ulcers that may lead to visual impairment or blindness.

Contact lenses for vision correction and therapy in vision disorders, such as myopia or astigmatism, are classified as medical devices and have to be registered with the Health Sciences Authority (HSA) before sale. This ensures conformity to the required standards of safety, performance and quality.

All importers and wholesalers dealing with such devices must obtain the relevant certifications and licence(s) from HSA. Anyone caught importing these contact lenses for sale without an import licence, or supplying unregistered or counterfeit contact lenses, can be fined up to $100,000 and/or jailed for up to three years.

From 2012 to last year, two persons were fined $4,000 and $12,000, and one was sentenced to community service, for these offences.

Since September 2011, HSA has rolled out initiatives to raise public awareness of the dangers of buying contact lenses from dubious sources. HSA has also reached out to online marketing sites to educate them on the regulatory requirements.

In Singapore, companies cannot sell contact lenses directly to consumers, including online. Companies can supply contact lenses only to qualified persons.

Under the Optometrists and Opticians Act, only registered optometrists and contact lens practice opticians can prescribe, supply and dispense contact lenses. Unqualified persons who prescribe, supply or dispense contact lenses may face up to a $25,000 fine, six months' imprisonment or both for a first offence, and up to a $50,000 fine, 12 months' imprisonment or both for a second or subsequent offence.

From 2012 to last year, six persons were prosecuted for such offences. Five persons were fined between $1,500 and $5,000. The case against the sixth person is still before the courts.

We will continue to maintain our close surveillance efforts and take the relevant enforcement and public health action to ensure the safe use of contact lenses in Singapore.

Lim Bee Khim (Ms)
Director
Corporate Communications
Ministry of Health

Raymond Chua (Assistant Professor)
Group Director
Health Products Regulation Group Health Sciences Authority

Harold Tan (Dr)
Registrar
Optometrists & Opticians Board

ST Forum, 18 Jan 2015

Constant monitoring needed to reduce risk

SINGAPORE Optometric Association president Koh Liang Hwee suggested that contact lenses per se do not cause eye infections, and that orthokeratology (Ortho-K) contact lenses are no riskier than other contact lens types worn overnight ("Safe to wear contact lenses, if proper care is taken"; Jan 11).

Many studies confirm that contact lens wear is associated with a low but significant risk of severe sight-threatening corneal infections.

Our recent Singapore study shows that contact lenses are responsible for two-thirds of all corneal infections.

It is also well recognised that overnight contact lens use is the main risk factor for corneal infection, with the highest risk among those who use soft contact lenses overnight, which is now not recommended, owing to safety concerns.

Over the last few years, a series of independent reports of Ortho-K-related infections surfaced worldwide, with more than 100 cases reported in many countries, including Singapore.

In 2008, the American Academy of Ophthalmology reviewed the safety of overnight Ortho-K lens wear and stated that a wide margin of safety should be built into these orthokeratology regimens, and called for more safety studies.

Most recently, a 2013 United States study confirmed that in children (the majority of Ortho-K wearers), the risk of infection using these lenses overnight is 13.9 per 10,000.

This is similar to the high risk in adults wearing soft contact lenses overnight.

In contrast, the average risk in all contact lenses is only approximately five per 10,000 users.

Experimental studies in animals have also confirmed that Ortho-K lens wear causes direct surface damage to the cornea and greater attachment of bacteria to the corneal surface, enhancing the risk of infection.

While some evidence suggests that Ortho-K lenses may possibly be used for myopia control in young children, the potential risks of overnight Ortho-K lens wear should be clearly explained to parents and children.

Contact lens practitioners offering Ortho-K treatment have a professional duty to remain vigilant, perform regular examinations to recognise early infections, and refer cases promptly for diagnosis and medical treatment.

Contact lenses do have a significant role as a form of vision correction, but constant surveillance by eye-care professionals, the patients themselves and the contact lens industry is needed to minimise risks.

Current regulations require that all brands of contact lenses purchased here be approved by the Health Sciences Authority, and that only trained and registered contact lens practitioners can prescribe them.

Donald Tan (Professor)
Senior Adviser, Singapore National Eye Centre

Lim Li (Adjunct Associate Professor)
Head, Contact Lens Service and Co-Head, Corneal Department, SNEC

Wong Tien Yin (Professor)
Medical Director, SNEC
ST Forum, 19 Jan 2015