Dr Laura Downie
BOptom PhD(Melb) PGCertOcTher FAAO FACO DipMus(Prac) AMusA
Age-related macular degeneration (AMD) is a leading cause of blindness in developed countries, accounting for more than 50 percent of blindness in Australia.1 With an ageing population, the number of Australians with AMD is predicted to almost double over the next 20 years.1
While treatments for late-stage neovascular AMD exist, in the form of intravitreal vascular endothelial growth factor inhibitors, there is currently no approved treatment for earlier stages of AMD or one of the two late stages of AMD, geographic atrophy.
At present, attenuating the progression to late-stage disease is the most valuable approach to reducing vision loss and the associated individual and community burden of AMD.
High quality evidence exists relating to the natural history of AMD2 and in particular, the benefit of lifestyle modifications relating to smoking cessation and nutrition, for reducing the risk of progression to late-stage AMD. Cigarette smoking, which almost doubles the risk of developing AMD,3 is the most important modifiable risk factor.4 A direct association also exists between the number of cigarettes smoked over time and the risk of late-stage AMD.5
While there is relatively strong public awareness about the systemic disease associations with smoking, including cancer, heart disease and stroke, knowledge of the link between smoking and blindness is less well recognised.6
To address a need for enhanced community awareness of this potential side-effect, for the past eight years the Australian Government has strongly supported advertising campaigns aimed at educating people of the ocular risks of smoking. These forms of public awareness programs have been shown to be of value for changing smoking behaviours.7,8
Nutrition is another important area for AMD risk modification in primary eye care. As recently reviewed,9 there is a wealth of epidemiological data that confirm the potential benefit of a healthy diet, rich in the macular carotenoids (zeaxanthin and lutein) and omega-3 long-chain essential fatty acids (EFAs), for lowering the risk of developing late-stage AMD.
Two large, National Eye Institute- sponsored, multi-centre, randomised, controlled clinical trials, namely the Age-Related Eye Disease Study (AREDS)2 and AREDS2,10 have evaluated the safety and efficacy of high dose antioxidant dietary supplements for AMD. AREDS 2 showed that daily consumption of a specific combination of antioxidant vitamins and nutrients could reduce the risk of progression from intermediate-stage to late-stage AMD from 28 per cent to 20 per cent over five years.
Clearly the decision to recommend such formulations to patients requires consideration of the patient’s systemic health status, as well as the relative benefits versus risks of the intervention.
As key providers of primary eye care in the community, optometrists play an important public health role in providing advice to patients about the major modifiable risk factors for ocular disease.
In recent years, studies have been undertaken to gain insight into self-reported optometric practice behaviours in these areas. Overall, findings from these studies, which have surveyed clinicians in a range of developed countries11-14 including Australia,15 suggest that there is scope for advice about smoking cessation to be more proactively provided by optometrists to their patients. A study conducted in the United Kingdom also reported a need to improve awareness among optometrists about the research evidence underlying the use of nutritional supplements for AMD.11
In 2013, Associate Professor Peter Keller and I undertook a study to examine self-reported optometric clinical behaviours in the areas of smoking and nutrition, in order to gain further understanding of the clinical practices of Australian optometrists. The paper from this study has been accepted for publication in the open-access refereed journal PLoS One.
The results of the study indicated that fewer than 50 per cent of respondents would routinely question their patients whether they smoked. Many respondents indicated that they considered smoking counselling to be a medical issue that was the responsibility of the patient’s general medical practitioner. Other common reasons that were cited by practitioners for not routinely providing advice about smoking cessation were a lack of time, a perception that there was sufficient advertising about the health risks associated with smoking and that this type of questioning was too personal or intrusive.
Almost two-thirds of respondents indicated that they would routinely counsel patients about their diet and about half specified routinely asking their patients if they were taking nutritional supplements. Optometrists who recommended nutritional supplementation to their patients most commonly did so for AMD (91.2 per cent) and dry eye disease (63.9 per cent). Of the supplements recommended for AMD, the most common were various forms of high-dose antioxidants (89.8 per cent) and omega-3 EFAs (8.5 per cent).
Our findings are similar to those reported in other parts of the world and suggest that overall, there is scope for optometrists to undertake improved questioning and counselling to patients about smoking status and nutrition, which are the key modifiable risks factors for AMD.
Through the award of a 2015 NHMRC Translating Research Into Practice (TRIP) Fellowship, I am undertaking a two-year project, with Associate Professor Keller as my TRIP mentor, which aims to improve the translation of research evidence into clinical practice by optometrists, in relation to modifiable risk factors for AMD. This is the first TRIP Fellowship to have been awarded to an optometrist.
A major component of the project is the creation of a new AMD optometric clinical teaching centre at the University of Melbourne Eyecare clinic.
This AMD Clinical Teaching and Demonstration Service (CTDS) will be made available for Victorian optometrists to attend, at no cost, towards the end of 2015. Optometrists who participate in the program are expected to receive accredited continuing professional development points. The key outcome of the project is predicted to be enhanced primary eye care delivery to patients with early stages of AMD.
- Deloitte Access Economics - Macular Disease Foundation. ‘Eyes on the future: A clear outlook on age-related macular degeneration’. 2011.
- The Age-Related Eye Disease Study (AREDS) study group. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol 2001; 119: 10: 1417-1436.
- Evans JA, Fletcher AE, Wormald RP. 28,000 cases of age related macular degeneration causing visual loss in people aged 75 years and above in the United Kingdom may be attributable to smoking. Br J Ophthalmol 2005; 89: 550-553.
- Thornton J, Edwards R, Mitchell P et al. Smoking and age-related macular degeneration: a review of association. Eye (Lond) 2005; 19: 935-944.
- Khan JC, Thurlby DA et al. Smoking and age related macular degeneration: the number of pack years of cigarette smoking is a major determinant of risk for both geographic atrophy and choroidal neovascularisation. Br J Ophthalmol 2006; 90: 75-80.
- Handa S, Woo JH, Wagle AM et al. Awareness of blindness and other smoking-related diseases and its impact on motivation for smoking cessation in eye patients. Eye (Lond) 2011; 25: 9: 1170-1176.
- Carroll T, Rock B. Generating Quitline calls during Australia’s National Tobacco Campaign: effects of television advertisement execution and programme placement. Tob Control 2003; 12: ii40-ii44.
- Kennedy RD, Spafford MM, Behm I et al. Positive impact of Australian ‘blindness’ tobacco warning labels: findings from the ITC four country survey. Clin Exp Optom 2012; 95: 6: 590-598.
- Downie LE, Keller PR. Making sense of the evidence: the Age-Related Eye Disease Study 2 (AREDS2) Randomized Clinical Trial. JAMA Ophthalmol 2014; In press.
- The Age-Related Eye Disease Study 2 (AREDS2) study group. Lutein + Zeaxanthin and Omega-3 Fatty Acids for Age-Related Macular Degeneration. JAMA 2013; 309: 2005-2015.
- Lawrenson JG, Evans JR. Advice about diet and smoking for people with or at risk of age-related macular degeneration: a cross-sectional survey of eye care professionals in the UK. BMC Public Health 2013; 13: 564.
- Thompson C, Harrison RA, Wilkinson SC et al. Attitudes of community optometrists to smoking cessation: an untapped opportunity overlooked? Ophthal Physiol Opt 2007; 27: 389-393.
- Caban-Martinez AJ, Davila EP, Lam BL et al. Age-related macular degeneration and smoking cessation advice by eye care providers: a pilot study. Prev Chron Dis 2011; 8: 6: A147.
- Brûlé J, Abboud C, Deschambault E. Smoking cessation counselling practices among Québec optometrists: evaluating beliefs, practices, barriers and needs. Clin Exp Optom 2012; 95: 599-605.
- Downie LE, Keller PR. The self-reported clinical practice behaviors of Australian optometrists as related to smoking, diet and nutritional supplementation. PLoS One 2015. Accepted 14 March 2015.