Letter: Plastic - friend or foe?
The urgent need to reduce plastic usage in contact lens manufacture
Author: Ron Hamilton, Executive chairman, Daysoft
The timely article ‘View from the British Contact Lens Manufacturing Association (BCLA)’ in Optician, 7.9.18, stresses the need for manufacturers to encourage the recycling of plastic used in contact lens manufacture. The article claims: ‘Plastic is the scourge of the planet right now, polluting our oceans and having a hugely detrimental impact on the environment.’ While there is obvious merit in the encouragement to recycle plastic, which the article does, there is a much more fundamental approach needed, that is, to reduce its use.
A review of the various contact lens manufacturing technologies shows the almost universal reliance on cast moulding technology. This involves the manufacture of three separate carefully engineered plastic components (excluding the lens itself, which requires a miniscule amount of biocompatible polymer). One concave optical-moulding is required to form the front surfaces of the lens while another convex optical-moulding is required to form the back surfaces of the lens. After lens formation, the lens then has to be transferred to the third, and largest, moulding which is used to contain the lens and packing liquid ready for foil-lidding and sterilising before storage and shipping to the wearer. Hundreds of millions of contact lenses are made each year using cast moulding with little more than superficial design variation between manufacturers (the relevant patents having long-since expired) with scant regard being given to minimising the weight of plastic used – until now.
Improving on the above tried-and-tested cast moulding technology has not been easy but, following many months of design, re-design, and experimentation, Daysoft has achieved its goal of reducing the number of mouldings required from three to two and the amount of plastic needed by over 50%.
For example, the accompanying image compares the design of the traditional blister pack as used for J&J Acuvue daily-disposable lenses compared to Daysoft’s latest pack design. The weight ratio is almost 3:1. Daysoft’s widely patented technology is named INPAC and its roll-out is scheduled to continue throughout 2018.
As the name implies the lens is made entirely inside the concave optical moulding which, in turn, becomes the final pack or ‘blister’. Transferring the lens from one mould to the final pack is not necessary thereby generating quality improvements and significant labour savings. The production of only two moulds, not three, and miniaturising the pack mould, not only greatly reduces the amount of plastic required but ensures the lens is always presented ‘right-way-up’ for easy time-saving ‘one-touch’ handling by the wearer. And to complete the story, the plastic used for INPAC is fully recyclable.
Lastly, it would be remiss of me not to mention the huge contribution plastic materials have made, and continue to make, to improving modern living conditions, including in health-care applications. It is, after all, not plastic which pollutes but humans. Let us include ‘educate’ with the calls to ‘reduce’ and ‘recycle.’