A recent study by Nick Atkins shows how Safilens’ daily disposable CL uniquely approaches the problem of contact lens induced dry eye

Thanks to the application of new biomaterials over the last ten years, contact lens technology has taken some important steps forward to be able to improve the wellbeing of contact lens users. However, conditions such as dry eye syndrome, eye dehydration, increased osmolarity and deposit build-up are clinical implications of primary importance. These conditions are often the origin of pathologies and declines in comfort.

With the introduction of Fusion 1day Safilens seeks to offer its customers an exceptional comfort wearing experience and a new approach for tackling “contact lens induced dry eye” or CLIDE.

Fusion 1day contact lenses are made from Fusion Technology, a patented material technology based upon the unique synergistic action of tamarind seed polysaccharide and high molecular weight hyaluronic acid obtained by biotechnologic synthesis. Fusion 1day material is composed of two polymers; the synthesised polymer (Filcon IV) constitutes the solid structure of the lens while the watery part is enriched with the natural bi-polymer of hyaluronic acid and tamarind seed polysaccharide as well as other minerals. The HA-TSP bi-polymer is claimed to support longer lens hydration as well as the continuous lubrication and stabilisation of the pre-corneal tear film, thus improving subjective comfort while wearing the lens.

HA – a naturally occurring linear-structured polysaccharide that is found in the aqueous and vitreous humour, the synovial fluid of joints, in heart valves and the skin – has been shown to increase tear break-up time. TSP is a natural, water-soluble, branched-chain polysaccharide and it has been found to have numerous properties that make it ideal for use as a tear film supplement.

Researchers evaluating the development of formulations containing both HA and TSP found a synergistic effect with the resulting bi-polymer demonstrating a higher capacity to encompass water when compared to each individual polymer. The prescriptive daily use of this solution formulation on the inside of the lens could lengthen both the comfortable, as well as the actual wearing time.

The big challenge to researchers was to somehow incorporate the HA-TSP bi-polymer within the soft lens substance to allow its release with wear. This was possible due to the bi-polymers property of thermoreversibility. Heating the solution to over 100°C results in the polymer chains becoming disorganized and passing into a more liquid state. In this state it is possible to introduce the polymer evenly within the soft gel matrix and, when it is subsequently cooled, it recovers its organized state within the hydrogel material. Another temperature increase, for example to the ‘on eye’ temperature of around 36°C, results in some increase in fluidity, so allowing a gradual release of the HA-TSP bi-polymer from the lens into the tears.
In conclusion, Fusion 1day, with its patented material containing the bi-polymer of hyaluronic acid and tamarind seed polysaccharide, has the real potential to be especially helpful for patients with CLIDE as well as first-time contact lens wearers. That is why it represents a very welcome addition to the contact lens fitters armoury in the ongoing battle to maximize comfortable wearing times and reduce the drop-out of contact lens patients.