No More Tears: Testing for Dry Eye Made Easy

14 June 2009 (Last Updated June 14th, 2009 18:30)

Nanotechnology is being incorporated into a new design to help dry eye sufferers around the world. Natalie Coomber investigates this new approach and how it is bringing product success.

No More Tears: Testing for Dry Eye Made Easy

For dry eye sufferers, the feeling of irritation experienced with the condition is often compounded by the intrusive or painful testing and treatment methodologies used in today's healthcare system.

Normal vision requires a healthy ocular surface where a sufficient quality of tears is coupled with a normal tear film, lid closure and regular blinking. When these elements become imbalanced, dry eye syndrome (also known as keratoconjunctivitis sicca) can occur, causing a great deal of pain for the sufferer.

More specifically, dry eye is a disorder of the tear film caused by tear deficiency or excessive tear evaporation. Critically, testing for the disorder has until now been a arduous process that is carried out in a laboratory environment while the sufferer's condition is left to worsen.

Getting critical acclaim, however, is a product invented by US company TearLab Corporation and developed by Invetech for fast and pain-free testing of the syndrome. The product allows testing to be carried out in record time and in an ophthalmologist's surgery.

According to the UK's National Health Service, 17–30% of people will experience dry eye during the course of their life. To date, there has been no technology that can quantitatively and objectively measure the condition in a doctor's office. The new TearLab Osmolarity System hopes to change that, but its success is about more than just meeting a gap in the market. TearLab and Invetech's Osmolarity System is also the result of careful design, planning and medical thought.

"According to the UK's National Health Service, 17–30% of people will experience dry eye during the course of their life."

Careful consideration

After being invented by TearLab Corporation's chief executive Eric Donsky, Invetech stepped in to make the TearLab Osmolarity System commercially viable for the mass market. Invetech managing director Dr Fred Davis says the company more than just played the part of engineering consultants; they created an entire business model for the system. "Ultimately, it is Eric's product, our job is to develop it for him," says Davis. "We evolved a design together, we then took that design and tested it, improved it and finished it. We enabled him to take the product to market faster because he didn't have the resources to do all that himself."

The patented approach includes a handheld pen that collects samples from the corner of the eye. It uses nanotechnology to collect just 50 nanolitres of tear samples, before using microfluidic technology and miniaturised electronics to provide a quantitative measurement. The doctor and patient can then view this within seconds once it has been transferred to a computer screen.

The complexity of the testing procedure meant that testing for dry eye could only be done with extremely complex laboratory equipment that an ophthalmologist wouldn't be able to use in their practice. "There was a scientific way of measuring it but there was nothing on the market that could really solve this problem," Davis says.

Pleasing the patient

Although the technology used is impressive, the real success comes with the way the product's design and development addressed the element of human factors. The techniques that have been used to minimise patient discomfort have won the product a medical design excellence award and ensured positive feedback from healthcare experts around the world.

"A priority in the product's design was making it non-threatening to the patient."

Davis says a priority in the product's design was making it non-threatening to the patient. Having tear fluid collected from the eye can make the patient feel vulnerable so ergonomics has to be taken into account, especially for it to receive CLIA waiver status. This CLIA categorisation is designed for products that can be defined by their use of unprocessed specimens, their ease of application and the minimal risk they present in producing an inaccurate result.

In addition to being more comfortable for the patient, Invetech says that the TearLab Osmolarity System is more accurate as results can be obtained on the spot with no dilution or evaporation of the tear sample. "It is fast because you can do it in the ophthalmologist's office, it is cheaper because you don't have to use a piece of expensive equipment and it is more comfortable because there is no contact with the eye," says Davis.

The practice of putting patients' needs at the centre of design considerations is something that is frequently ignored, says Invetech director of biomedical instruments and devices Andreas Knaack. "It is a generic medical device problem, with the eyecare industry just being a small area of that," he says. "US Food and Drug Administration statistics show that most medical device errors and issues come out of poorly designed products. Spending a bit longer thinking about how can we prevent these hazards, making the use easier for the operator and more pleasant for the patient, is well-invested time."

"Early detection is vital in tackling the problem, which only adds to the success of the Invetech and TearLab product."

Seeing clearly

In its most extreme form, dry eye can lead to scarring of the cornea and conjunctivitis. Acute sensitivity to light and poor vision are also potential effects. Some sufferers have an underlying problem that may be causing dry eye and can be cleared up with independent treatment, but nearly all will also experience chronic inflammation of the rims of the eyelid, otherwise known as blepharitis.

While some may resort to specialist eyewear or surgery, tear substitutes are the most common form of treatment. These liquids are designed to mimic the property of tears and most contain a preservative to help prevent evaporation.

Like so many illnesses, early detection is vital in tackling the problem, which only adds to the success of the Invetech and TearLab easy-to-use, ergonomically designed product. The product is already available in Europe and major players such as the German Society of Ophthalmologists have pledged support. Getting the problem diagnosed early is half the battle – the TearLab Osmolarity System should make it an easier fight to win.