Executive Director of Research & Development: Dr Eric Papas, IER
Program Director: Padmaja Sankaridurg, IER
Background
Myopia (short-sightedness) is reaching epidemic proportions, especially in Asia, due to urbanisation and increased screen and text-based activity throughout all aspects of our daily lives. For example in Singapore a series of studies has shown an increase in myopia in males aged 15-25, from 26% of this group in the late 1970s, to 83% in the late 1990s.In Taiwanese children, the incidence of myopia rose dramatically from 4% in 1986 to 16% in 2000 and the prevalence of myopia in school children aged 16 to 18 years to 84%. The number of myopes in the world is estimated to grow from 1.6 billion now to a staggering 2.5 billion by 2020.
If left undetected and uncorrected, myopia can adversely affect a child’s education and learning ability. Myopia also doubles the risk of serious eye problems such as glaucoma or retinal detachment, which can cause permanent vision loss, even blindness. Visual impairment due to uncorrected refractive error (<6/18 in adults and <6/12 in children) has been estimated to affect as many as 200 to 250 million people worldwide.
The expected increase in the number of people with myopia in the near future represents an immense market for Vision CRC optical devices.
Continuous wear contact lenses that provide optimal comfort, vision & biocompatibility
Contact lenses provide a convenient vision correction option for many people. The highly successful continuous wear silicone hydrogel contact lenses produced by CRCERT and CIBA Vision have solved the problem of hypoxia, and are providing the convenience of flexible wear schedules to growing numbers of users worldwide. However a truly biocompatible contact lens is still needed to provide optimum comfort and ocular health. Symptoms of dryness and discomfort affect a significant percentage of contact lens wearers and are the key hindrance to more widespread adoption and expansion of the market. Vision CRC is characterising contact lens comfort by examining the effects of lens design, lens material characteristics, mode or length of wear, and the interactions of contact lenses with both lens care systems and tears. This research will be translated into novel lens designs and materials, including surface treatments, to improve ocular comfort during wear. Work is also progressing in research into novel anti-bacterial strategies for contact lenses.
Contact lens safety
The Vision CRC, in collaboration with the IER and CCLRU, have also conducted a major study into rates of corneal infection with contact lenses, and the risk factors associated with infection. Contact lenses are worn by almost three quarters of a million people in Australia and serious complications of contact lens wear are uncommon. Corneal infection is the most severe and potentially sight-threatening complication of lens wear, occurring in approximately 5 in 10,000 contact lens wearers annually.
The 12 month study, which included surveillance of all eyecare practitioners in Australia and New Zealand and a telephone survey of 30,000 households, has shown that the lowest risk of infection is associated with daily use of rigid gas permeable lenses and with daily disposable lens use. Although new highly oxygen permeable soft lenses have provided numerous ocular health benefits and allowed more wearers to use the lenses for longer periods for both daily and extended wear, the risk of infection remains higher in extended wear regardless of the lens material. Hygiene was shown to be a key risk factor, and the promptness of treatment was key to infection outcome. These findings are important in the management of lens related disease and will help to direct future research into the safety of contact lens wear.
Affordable contact lenses
Development of affordable and highly oxygen permeable contact lens materials that meet the criteria for ocular health are critical to the growth of the contact lens market. During the second year of the Centre a lower cost, silicone hydrogel lens was developed primarily for daily wear, in conjunction with CIBA Vision. The Australian launch of the O2Optix contact lens took place in early 2005 and global sales are currently well in line with industry projections. Work has continued within the Vision CRC to extend the wearer base for this product by increasing its range of applicability and maximising the performance of both this and existing silicone hydrogel contact lenses.
Corneal onlay
The corneal onlay project (which follows on from the CRCERT Implantable Contact Lens Project) is developing a permanent correction for refractive errors with an implantable contact lens. A synthetic lens is surgically placed under the superficial layer of corneal tissue (the epithelium), altering the corneal curvature. The lens is designed to provide stable vision for at least five years, while being a reversible procedure in which no permanent functional or structural damage is done to the eye. Surveys of key vision practitioners globally have indicated that reversible procedures such as corneal onlays represent the future for permanent surgical correction of refractive error.
During Year 2 of the Vision CRC, research continued to focus on the optimisation, reproducibility, biocompatibility and transparency of the highly porous perfluoropolyether (PFPE) polymers that were previously selected for onlay materials. During Year 2 a prototype implantable lens was tested in phase 1 clinical trials. These tests have demonstrated good results in terms of polymer biocompatibility, transparency and clinical tolerance and are continuing in year 3.
Anti-myopia products that arrest, slow or control the progression of myopia
As the eye develops, it is theorised that the quality of images focussed on the retina affects the process of ‘emmetropisation’ (where the eye grows to an ideal state to provide normal vision). If the images are not sharp, then the eye can grow too large, resulting in myopia (shortsightedness).
Research from the Vision CRC and its participants suggests that the ability to focus images on the peripheral retina may influence emmetropisation. A novel optical device that controls image formation in this region may be a major breakthrough in eliminating or slowing the progression of myopia. Vision CRC anti-myopia optical designs are currently being tested for feasibility. A large scale human clinical trial involving 400 participants has commenced in the UK.
Strategic research is working to further understanding of the contribution that genetic and environmental influences have on the development of myopia. Outcomes from this research will provide valuable input into product-specific areas. Currently, Vision CRC strategic research is screening large numbers of individuals and their families in Australia and India for genes that may cause myopia, and is examining the interaction between heredity and environmental influences in a large group of Australian twins. Vision CRC is also collaborating with the Sydney Myopia Study to conduct a large population-based investigation of the prevalence of myopia in Sydney school children and to examine the relationship between myopia and environmental factors such as near work, education and lighting conditions. More than 1600 children aged 6-7 years have been examined, and examination of children aged 12-13 will be complete by the end of the year.
Myopia Program participating organisations
Anglia Polytechnic University, Department of Optometry and Ophthalmic Dispensing; Centre for Eye Research Australia; CSIRO Molecular Science; Institute for Eye Research; LV Prasad Eye Institute; Queensland University of Technology, School of Optometry; University of Houston, College of Optometry; University of Sydney, Centre for Vision Research, Westmead Millennium Institute.
Industry Partner: CIBA Vision (Improved continuous wear; and Affordable contact lenses) |
