Australian researchers from the Institute for Eye Research (IER) say they are now close to developing what they term the “perfect contact lens – one that fits perfectly over the eye and is inflammation-free.”
The research projects have already produced a range of promising findings, which are due to be published in several prestigious clinical and basic science journals.
The invention of the contact lens as a convenient and effective alternative to spectacle wear has been a significant advance for people with vision disorders. While infection associated with contact lens wear is extremely rare (4 in 10,000 daily wear and 20 in 10,000 extended wear contact lens wearers annually) the Institute for Eye Research is conducting a series of research projects aimed at the development of the ‘perfect contact lens’.
It describes this as a lens that will not only provide excellent vision correction and fit the eye perfectly, but also eliminate the possibility of any inflammation caused by contact lens wear, especially as a result of bacterial build up.
According to Professor Mark Willcox, Chief Scientific Officer at the Institute, researchers have been conducting investigations into whether contact lens wear carries increased risk of infections if worn by children and new ways to minimise microbial adhesion to lenses. Professor Willcox said: “These studies, which observed contact lenses wear in children, demonstrated that bacteria are occasionally present in the eyes, even without contact lens wear.
“The types of bacteria that colonise the eye during contact lens wear in children were not different to those in adults. This suggests that there is no increased risk of infection for children wearing lenses.
“To further improve the safety of contact lenses during wear, the Institute has been developing new ways to minimise microbial adhesion to contact lenses. Two publications due to come out soon are the first to demonstrate the utility of this research effort.”
Tear Film Research
As part of its ‘Perfect Contact Lens’ programme, the Institute will continue its investigations into the tear film, which provides the lubrication and protection necessary for the eye to function normally.
“The significance of this work is that some of the proteins and lipids in the tear film can deposit on lenses during wear. The latest publications are the first to demonstrate the types of proteins and lipids that can deposit on the new silicone hydrogel contact lenses during wear,” said Professor Willcox.
“Using new techniques in this field, the Institute’s researchers have identified that certain tear film proteins, as well as proteins from fingers during lens insertion and removal, can deposit on lenses. The next stage in these investigations is to determine whether any of these proteins are associated with discomfort during lens wear or indeed other clinical problems that occur during lens wear”.
The Institute is also working to develop a greater understanding of the causes of ‘dry eye’, one of the major reasons people seek eye care. Dry eye affects a significant percentage of the population and people suffering from the condition can complain of a persistent feeling of ocular dryness and itchiness, which may trigger excessive blinking.
This research, supported by a grant from Allergan Inc., U.S.A. has demonstrated that a compound called carnitine may help protect the cornea and conjunctiva during dessication (dry eye).
Findings presented to U.S. Academy
Researchers from the Institute for Eye Research presented important findings from the ‘perfect lens’ projects at the American Academy of Optometry annual meeting – the biggest event on the international optometric calendar. Jerome Ozkan, a research optometrist at the Institute, presented findings on selenium coated antibacterial silicone hydrogel lenses, which have been developed as part of the Institute’s program.
The selenium coated lenses have proven to inhibit bacterial colonisation, a significant breakthrough in creating a lens that will help to prevent inflammatory events of the eye.
Jerome’s study assessed the clinical safety of selenium coated lenses. It demonstrated that the overall clinical performance of the lenses over 24 hours wear was comparable to the commercially available lens; an important finding in the development of this new lens.
“We no longer have problems with hypoxia thanks to silicone hydrogel lenses and we now need to create a lens that eliminates, or significantly reduces, the risk of inflammation and infection with contact lens wear. This study is an important step in that direction,” he told the Academy.
A larger scale, continuous wear trial, is planned to further assess the efficacy and safety of selenium-coated antibacterial lenses.
Dr. Jennifer Choo presented results from Orthokeratology (OK) studies conducted at the Institute. Orthokeratology is a contact lens procedure that involves the overnight wear of specially designed contact lenses.
These lenses reshape the cornea while the patient sleeps so that upon awakening and lens removal, the patient experiences clear vision throughout the day without the need for glasses or contact lenses.
Dr. Choo’s poster presented important results from her work investigating the changes that occur in the corneal epithelium with increasing OK lens wear. The epithelium is the outermost layer of the cornea – the transparent front surface of the eye that helps the eye to focus.
Dr. Choo’s research sought to gain further insights on earlier studies, which indicated substantial changes in epithelial thickness, occurred whereby the central epithelium thinned and the mid-peripheral epithelium thickened with myopic OK. The study confirmed these earlier results.