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Thursday / May 26.
HomemieyecareDiscovering the Revolutionary Flat-Pack Contact Lens

Discovering the Revolutionary Flat-Pack Contact Lens

Based in Japan, Menicon, which distributes to 88 countries around the world, has launched the Miru contact lens, a revolutionary flat-pack lens that comes securely sandwiched between super-thin foil sheets that can easily be opened, even with wet hands.

Once opened, the Miru contact lens, which is slightly compressed, ‘raises up’ and presents with the outer convex side (front curve) facing upward, ready for placing on the cornea with minimal handling.

The innovator behind the Miru lens is Steve Newman, Managing Director of Menicon Singapore.

Mr. Newman has a pedigree in the contact lens industry having worked in research and development with Hydron for over a decade before establishing Capricornia Contact Lenses in Australia in the late 80s with long-time mentor Don Noack. He then moved to Singapore to manage the Igel group and its sale to 1-800-Contacts. It was here, at 1-800-Contacts, that Mr. Newman oversaw various lens and process initiatives, one
of which was ‘flat pack technology’.

Once opened, the slightly compressed lens ‘raises up’ and presents with the outer convex side (front curve) facing upward, ready for placing on the cornea with minimal handling

The idea of the flat pack found its genesis about a decade ago when Mr. Newman shipped lenses to Australia.

“They were flattened discs in plastic presentation slide sheets that were heat-welded closed,” said Mr. Newman. “The lenses stayed hydrated during their journey. Our customer peeled off one side of the plastic sheet to remove the lenses and then washed and sterilised them at his laboratory.

“From this experience, I knew that certain soft lenses could remain flattened for a long period without adverse effects. I believed that with an appropriate peelable foil structure, we could place a lens into the pack, sterilise it via an autoclave and then deliver the pack directly to patients, whereupon they could remove the lenses by peeling back the foil. I discussed this with our packaging partner and asked him if he could develop a suitable foil to satisfy these criteria, which he did.

“Patient health and safety is paramount to Menicon, so we were given the challenge to produce the flat pack to a quality standard over and above the industry norm.

According to Menicon research, one of the irritations for patients is the way they put their contact lens on inside out and then, to take them out, wash them, turn them and re-insert them.2

Mr. Newman said Menicon has aimed to address this by developing “a disc in our new packaging which holds the lens gently but securely in place so patients can only touch it from the outside surface. This means that handled correctly, the back surface of the lens has a minimal chance to be contaminated when it is inserted into the eye.”

“Secondly, patients are irritated by blister packs that are difficult to open. To open a traditional blister pack takes 18-22 newtons of force, while ours takes only three to four (Figure 1).

“Even if your hands are wet, they are easier to open. That means patients are less likely to use their teeth to access the lenses, and less likely to use so much force that the lens is flicked across the floor once the foil lid of the blister pack peels back.

“We wanted to create a daily lens that patients subconsciously associate with a daily use product. The packaging we came up with does that. It looks like a bandaid and once it’s opened, it can’t be re-used to store the lenses,” said Mr. Newman. (Figure 2a and 2b)

Barring Vaporisation

Whereas traditional blister packs are made from polypropylene, Miru packaging is made from aluminum foil. Mr. Newman said this enables Menicon to achieve a size advantage. “Polypropylene is not a particularly strong barrier to vaporisation, so over time, the saline solution used to protect the lenses can leach out. That means manufacturers have to put sufficient saline in so that even if you lose vapour, it won’t change the condition of the solution or lens inside the pack.

“Foil, on the other hand, acts as a 100 per cent barrier. This means the Miru lens can be stored in the smallest quantity of saline without the risk of the packaging drying out. We’ve proven that our packaging will not lose saline over a period of at least five years.”3

Made for Comfort

The material used to make the lens itself is not new but it has unique wearing attributes. “We chose to manufacture the Miru from poly (HEMA-GMA) (hioxifilcon A) with 57 per cent water content because of the end of day wetting success with this material.

“This is classified by the US Food and Drug Administration as Group II (high water content, nonionic material). GMA (glycerol monomethacrylate) has a molecular structure similar to HEMA (hydroxyethyl methacrylate), but two times more hydroxyl groups (-OH).

“The structure of the GMA chains found in (HEMA-GMA) is similar to the structure of oligosaccharide which makes up a significant proportion of mucin, the body’s own natural wetting substance, found in tears.1 Therefore, it is expected that the poly (HEMA-GMA) lens’ excellent hydrophilic property and water retention capability will lead to better comfort and less dryness,” he said.

“This is important because one of the biggest complaints3 from contact lens wearers is the dryness they experience at the end of the day. They want to get the same level of comfort at the end of the day as they get at the beginning or middle of the day.”

He said the Miru lens has been designed to block certain high order aberrations and to be identical regardless of power – so that a patient wearing two different powered lenses will not notice any difference in comfort levels. Additionally, in its efforts to maximise patient safety, all lenses are manufactured to the same mass with the same low level of residuals.

“We’ve achieved an extremely low level of residuals, below detectable limits when analysed via high performance liquid chromatography. Even though this level of purity is not required by the industrial compliance recommendations, it provides an added level of safety for patients,” said Mr. Newman.

To further ensure patient safety and hygiene of the product Menicon has turned the traditional manufacturing process on its head.

“We designed a vertical production line primarily to save on building costs – in Singapore where Miru is manufactured, land and buildings are expensive. What we’ve found is this also enables us to have greater control over the environment. In a traditional horizontal manufacturing plant, there are large conveyor belt systems moving the lenses from station to station with a greater possibility of contamination. Our vertical system is sealed as its own compact clean room, within a clean room environment, so we’ve got a double safety barrier,” he said.

Wow Factor

The Miru lens was launched in Japan in July (under the brand name Magic in Japan) and Mr. Newman said the response has been positive. “There’s the ‘wow’ factor with Miru, people have never seen a lens stored in such a thin pack and once they adapt to that, it’s hard for them to go back to the more bulky, more difficult-to-use blister pack.

Now Menicon is taking Miru to the world with patient and practitioner education campaigns rolling out globally.

For information on the Miru contact lens, contact Capricornia Contact Lens (AUS) 1300 650 994; Contact Lens Centre (AUS) 1800 125 023; Gelflex Laboratories (AUS) 1800 998 071 or Corneal Lens Corporation (NZ) 0800 954 536.

References

1. 1 Kruse A and Lofstrom T. Clinical evaluation of a biocompatible daily disposable contact lens. Optician, 2005;230:6022 30-33.1.23

2. http://www.optometricmanagement.com/articleviewer.aspx?articleID=105260

3. Menicon data on file

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