PolyDev, based in Dunleer, Ireland, is a leading manufacturer of low volume, high value toric cosmetic contact lens, bringing together art and technology to support the aesthetic needs of contact lens wearers. TORIColor is a monthly replacement Cosmetic Toric Lens available in a range of colours, and the only disposable lens with astigmatism correction. What’s more, it’s approved by the FDA for sale in the US, which means that the production facility has to meet the demanding standards of the US Food and Drugs Administration (FDA).
Contact lenses have to be sterilised prior to packaging, and PolyDev use an Astell 120 litre front opening ASB260 'Swiftlock' autoclave. Most small volume contact lens processors package their lenses in vials, but PolyDev package theirs in the more convenient blister packs. However, this sets some challenges. The customer’s task was to allow the safe sterilization of sealed contact lens blister packs prior to distribution. “It means that sterilisation has to be done in a carefully pressure-equalised manner as the temperature is raised, maintained and lowered in the autoclave chamber”, says PolyDev’s Dr John Mulvihill, “too much pressure and temperature applied too quickly could result in the delicate blister packs bursting or distorting. The Astell steriliser controls the process in a superb manner.”
Meeting the Challenge
To achieve this result, Astell designed a custom autoclave to meet the exacting requirements specified by PolyDev. The regular ‘316L-grade stainless steel’ circular sterilizer chamber was complemented with all-stainless-steel orbitally welded pipework, hygienic connections, and a stainless steel frame and panelwork to suit the manufacturing environment. The pressure vessel was fitted with a heating and cooling jacket system, along with a specially designed internal fan situated inside the chamber to maintain a constant steam/air mix throughout the heating and sterilisation phases. This had the added advantage of significantly reducing cooling times. Finally, the autoclave also included an integrated all-stainless-steel steam generator for fast, controlled steam production.
Astell and PolyDev worked closely together to develop bespoke software for the ASB260’s standard fitment touchscreen controller. This provides sterilisation programmes able to meet the requirements of a fully loaded chamber of liquid filled blister packs. This means ramped steam/air heating to avoid bursting the sealed packs, followed by a progressive controlled ramped cooling phase after sterilisation to prevent any distortion of the product through sudden temperature change.
“We chose Astell because they were willing to discuss and agree a user specification for a smaller unit than would be the norm with highly exacting requirements. The autoclave is reliable and consistent, as would be expected for a regulated, medical device production item, and the quality of the build is excellent”, says John.
The ASB260 120 litre front opening 'Swiftlock' autoclave has the following features:
- A fully programmable colour Touch Screen Controller with Intel E620T 333MHz processor
- Small footprint
- Data archiving for up to 5,000 cycles
- USB interface for downloading controller and cycle data
- 6 pre-programmed cycles, with the ability to add multiple additional cycles
- Password levels to stop unauthorised users making changes
- Optimised for low water and power consumption
- An advanced ‘pulsar’ vacuum system, ensuring effective air removal and efficient drying of surgical instruments
- Integral Steam Generator – no need for an additional onsite supply