Age-related macular degeneration (AMD) is the leading cause of blindness among people older than 55 years. Fifty-five million AMD patients live in North America alone, and 2.7 million new patients per year are expected. Compared with other elderly individuals, those who lose vision due to AMD enter nursing homes an average of 3 years earlier, suffer twice as may falls, have a threefold higher incidence of depression, sustain four times as many hip fractures, and die an average of 2 years earlier.1 These statistics demonstrate the value of identifying who is at risk of developing the disease.
macular pigment optical density
AMD is an oxidative process within the eye, much like rusting. High-energy blue light can cause oxidation of the retinal pigment epithelial layer, which leads to the formation of drusen. Free radicals—unstable molecules formed in metabolic areas of the body, including the retina—contribute to the oxidation of the photoreceptors. Macular pigment both blocks blue light and quenches free radicals.2 A significant amount of research has found that insufficient levels of macular pigment optical density (MPOD) increases an individual’s risk of developing AMD by as much as 40%.3,4
Although the risk factors for AMD include immutable characteristics that cannot be changed such as genetic history, gender, and eye color, others such as cardiovascular disease and smoking status can be changed. By far, the easiest risk factor for eye care professionals to address with patients is MPOD, and its screening should become the standard of care in every eye care practice.
Eye care practitioners in my office have implemented a variety of measures to help patients understand the risk factors for AMD and focus on its prevention. The first step involves patients’ education. Using the ECHO tool (Eyemaginations Inc.), we send animated videos on AMD to every patient older than 45 years. They also view information on MPOD testing and dietary supplementation in the office’s waiting room and the examination lane.
Our second step is to incorporate MPOD screening into the comprehensive eye examination of every patient older than 21 years. Macular changes related to AMD are rare until patients exceed the age of 50; our goal is to identify problems before they result in structural changes to the retina or macula.
Macular pigment is made up of three carotenoids: lutein, zeaxanthin, and meso-zeaxanthin. As individuals age, it is very difficult for them to get sufficient levels of lutein and zeaxanthin in a normal diet. Studies have shown that oral supplementation of these essential nutrients increases MPOD and consequently can slow the progression of AMD.5,6
It only makes sense that a comprehensive eye examination should screen patients for the most common cause of blindness in the elderly. I advise my patients with low MPOD or average MPOD combined with other significant risk factors for AMD to take oral macular supplements.
Steven F. Sopher, OD, is chairman of the board and senior consultant to Eyemaginations Inc., and he practices at Lens ’n Eye in Baltimore. Dr. Sopher may be reached at (410) 882-2020; email@example.com
- Bressler NM. Age-related macular degeneration is the leading cause of blindness. JAMA. 2004;291:1900-1901.
- Loane E, Kelliher, C, Beatty, S, Nolan JM. The rationale and evidence base for a protective role of macular pigment in age-related maculopathy. Br J Ophthalmol. 2008;92(9):1163-1168.
- Delcourt C, Carriere I, Delange M, et al; the POLA Study Group. Plasma lutein and zeaxanthin and other carotenoids as modifiable risk factors for age-related maculopathy and cataract: The POLA study. Invest Ophthalmol Vis Sci. 2006;47:2329-2335.
- Zhou H, Zhao X, Johnson E, et al. Serum carotenoids and risk of age-related macular degeneration in a Chinese population. Invest Ophthalmol Vis Sci. 2011;52:4338-4344.
- Johnson EJ, Hammond BR, Yeum, KJ, et al. Relation among serum and tissue concentrations of lutein and zeaxanthin and macular pigment density. Am J Clin Nutr. 2000;71:1555-1562.
- SanGiovanni JP, Chew EY, Clemons TE, et al; the Age-Related Eye Disease Study Research Group. The relationship of dietary carotenoid and vitamin A, E, and C intake with age-related macular degeneration in a case-control study: AREDS Report No. 22. Arch Ophthalmol. 2007;125(9):1225-1232.