25th September 2017
Nearly all new contact lenses now use silicone as a vital component of the lens material - an innovation developed in Australia at the Brien Holden Vision Institute (https://www.brienholdenvision.org/translational-research/track-record.html). This was the second fundamental shift in soft contact lens technology after the advent of disposable lenses. The thinner and more comfortable disposable lenses allowed people to wear their lenses for longer and longer hours of the day and these long wear times started to cause signs in the eye of oxygen starvation. The front surface of the eye absorbs oxygen directly from the air and this normal source for oxygen is reduced once a contact lens is placed on the eye. Silicone transports oxygen very well and adding silicone dramatically increases the breathability of a contact lens material.
While silicone does a great job of making a contact lens material breathe, it’s feel is rubbery which makes it less soft, less flexible, less smooth and less able to drape over the eye. This means less comfortable than the soft lens materials it was designed to supersede. The result was adverse mechanical events - inflammation under the top eyelid from rubbing with blinks and curved abrasions at the top of the eye from lens edge inflexibility.
Coopervision (https://coopervision.net.au/contact-lenses/myday-family) has focused on ways to reduce the silicone content of their lenses while maintaining breathability. The MyDay lens uses longer chain silicone (https://coopervision.net.au/product-technology/smart-silicone) which due to its more continuous, less segmented structure creates a boost in oxygen transmission over regular silicone and enables reduction of total silicone content to a very low 4.4% for the same breathability. This also allows a high water content of 54%.
MyDay material lenses have been available in sphere powers for a while, but the range has expanded and it is now also available for 94% of astigmatism prescription. Speak with your optometrist today to see if you might be a good candidate for the MyDay soft contact lenses. Book online here or call us on (08) 8231 9341.