Hyaluronic Acid (HA) also known as hyaluronate is a mucopolysaccharide that occurs naturally in our bodies. It binds to water which results in a viscous gel and has been involved in literally thousands of trials in ophthalmology and orthopedics due to its ability to naturally bind to water and lubricate tissue. Believe it or not it was first patented in 1942 and most agree no other molecule has such remarkable qualities that benefit the human body and it is highly concentrated in the vitreous but in the 5th decade our body stops producing HA. Unfortunately here in the US we have not seen one successful study approved by the FDA for therapeutic ophthalmic use while in the EU, there are multiple products readily available. Several studies from over the pond have shown HA has an extremely beneficial effect in dry eye disease (DED) patients and the molecule has the ability to reduce osmolarity of the tear film for up to 3 hours; which in some cases is 50% longer that other tear supplements. I do have to be honest and report a couple of OTC drops currently available in the US have a low percentage of hyaluronate labeled as “a carrier” which is good, but having a therapeutic dose would be so much better for our patients, right?
In the current September 2014 Eye & Contact Lens, Guidi et al report results titled “Modification of timolol release from silicone hydrogel model contact lens materials using hyaluronic Acid”. The objective was to evaluate the ability of hyaluronic acid (HA) to act as a functional additive in model silicone hydrogel contact lenses to alter the uptake and release characteristics of timolol was investigated. Four different model lens compositions were explored: unmodified controls, lenses containing HA, lenses that were molecularly imprinted with timolol maleate, and those that were both imprinted and contained HA. This is an exciting step into the future for those that have access to this wonderful molecule outside the US that can not only help dry eye patients but even glaucoma patients. One has to wonder how long it will be before we can get access here.
You can read the abstract here.