A new study has investigated the pattern and progression of wet (also called neovascular) age-related macular degeneration (AMD), and determined that having wet AMD in one eye was associated with an increased incidence and progression of AMD in the other eye.
The researchers concluded that “AMD severity in one eye largely tracks AMD severity in the ‘fellow’ eye at all stages of the disease.” The study results clarify the symmetrical nature of AMD and may help physicians and patients communicate more clearly when discussing the course and prognosis of AMD.
From JAMA Ophthalmology
The research, entitled Severity of Age-Related Macular Degeneration in 1 Eye and the Incidence and Progression of Age-Related Macular Degeneration in the Fellow Eye: The Beaver Dam Eye Study, was published “online first” in the October 23, 2014 edition of JAMA Ophthalmology (formerly Archives of Ophthalmology). JAMA Ophthalmology is an international peer-reviewed journal published monthly by the American Medical Association.
The authors are Ronald E. Gangnon, PhD; Kristine E. Lee, MS; Barbara E. K. Klein, MD, MPH; Sudha K. Iyengar, PhD; Theru A. Sivakumaran, PhD; and Ronald Klein, MD, MPH, who represent the following institutions: the University of Wisconsin School of Medicine and Public Health, Madison; Case Western Reserve University, Cleveland, Ohio; and Cincinnati Children’s Hospital Medical Center, Ohio.
About Age-Related Macular Degeneration
Age-related macular degeneration (AMD) is gradual, progressive, painless deterioration of the macula, the small sensitive area in the center of the retina that provides clear central vision. Damage to the macula impairs the central (or “detail”) vision that helps with essential everyday activities such as reading, preparing meals, watching television, playing card and board games, and sewing.
AMD is the leading cause of vision loss for people aged 60 and older in the United States. According to the American Academy of Ophthalmology, 10-15 million individuals have AMD and about 10% of people who are affected have the “wet” type of AMD.
Wet (Neovascular) Macular Degeneration
In wet, or exudative, macular degeneration (AMD), the choroid (a part of the eye containing blood vessels that nourish the retina) begins to sprout abnormal new blood vessels that develop into a cluster under the macula, called choroidal neovascularization (neo = new; vascular = blood vessels).
The macula is the part of the retina that provides the clearest central vision. Because these new blood vessels are abnormal, they tend to break, bleed, and leak fluid under the macula, causing it to lift up and pull away from its base. This damages the fragile photoreceptor cells, which sense and receive light, resulting in a rapid and severe loss of central vision.
Risk Factors for Macular Degeneration
The primary risk factors for AMD include the following:
- Smoking: Current smokers have a 2-3 times higher risk for developing AMD than do people who never smoked. It’s best to avoid second-hand smoke as well.
- Sunlight: Ultraviolet (UV) light is not visible to the human eye, but can damage the lens and retina. Blue light waves that make the sky, or any object, appear blue, are visible to the human eye and can also damage the lens and retina. Living Well with Low Vision reports on these lighting issues in Artificial Lighting and the Blue Light Hazard. Avoid UV light and blue/violet light as much as possible by wearing sunglasses with an amber, brown, or orange tint that blocks both blue and UV light.
- Uncontrolled hypertension: The National Eye Institute (NEI) reports that persons with hypertension were 1.5 times more likely to develop wet macular degeneration than persons without hypertension. It’s important to keep your blood pressure controlled within normal limits.
- A diet high in packaged, processed food and low in fresh vegetables: NEI suggests that eating antioxidant-rich foods, such as fresh fruits and dark green leafy vegetables (kale, collard greens, and spinach) may delay the onset or reduce the severity of AMD. Eating at least one serving of fatty fish (salmon, tuna, or trout) per week may also delay the onset or reduce the severity of AMD.
- Race: According to NEI, Whites/Caucasians are more likely to have AMD than people of African descent.
- Family history: NEI reports that individuals with a parent or sibling with AMD have a 3-4 times higher risk of developing AMD.
You can read more about the full range of AMD risk factors at Risk Factors for Age-Related Macular Degeneration on the VisionAware website.
About the Beaver Dam Eye Study
The Beaver Dam Eye Study is funded by the National Eye Institute. The purpose of the Study is to collect information on the prevalence and incidence of age-related cataract, macular degeneration, and diabetic retinopathy, which are all common eye diseases causing loss of vision in an aging population. The study was designed to discover, or detect, causes of these conditions.
The study also has examined other age-related issues, including decline in overall health and quality of life and development of kidney and heart disease.
The study was initially funded in 1987. A private census conducted in the city and township of Beaver Dam, Wisconsin found that there were approximately 6,000 people aged 43 through 84 years. Approximately 5,000 of them participated in the baseline examination between 1988 and 1990.
Five-, 10-, 15-, and 20-year follow-up examinations have taken place and 3,700, 2,800, 2,100, 2,000, and 1,900 people participated in each of the respective examination phases. Thus far, there have been more than 300 publications describing the prevalence and incidence of visual loss, age-related macular degeneration, cataract, and associated risk factors as a result of this study.
You can read more about the study at the Beaver Dam Eye Study website.
About the Research
Excerpted from Progression of age-related macular degeneration in one eye then fellow eye via Medical Xpress:
Having age-related macular degeneration (AMD) in one eye was associated with an increased incidence of AMD and accelerated progression of the debilitating disease in the other eye, writes author Ronald E. Gangnon, Ph.D., of the University of Wisconsin School of Medicine and Public Health, Madison, and colleagues.
AMD is thought to be a symmetric disease, although one eye may precede the other in progression.
The authors examined the effect of severity of AMD in one eye on the incidence, progression and regression in the other eye. Data from 4,379 participants in the Beaver Dam Eye Study were used. Retinal photographs were used to assess the incidence, progression, and regression of AMD.
While more severe AMD in one eye was associated with increased incidence and accelerated progression in the other eye, less severe AMD in one eye was associated with less progression in the other eye.
“In a [patient group] that was observed for 20 years, we showed that AMD severity in one eye largely tracks AMD severity in the fellow eye at all stages of the disease. … Our model demonstrated the effect of one eye on the incidence and progression of AMD in its fellow eye across the entire continuum of AMD severity.”
More about the Study from JAMA Ophthalmology
From the article abstract:
Importance: Previous studies regarding the severity of age-related macular degeneration (AMD) in 1 eye and its prognostic implications for the fellow eye have focused on the incidence of neovascular AMD in the fellow eye of participants with neovascular AMD in the other eye. It is unclear to what extent the severity of AMD in 1 eye affects the incidence, progression, and regression of AMD in its fellow eye across the entire range of AMD severity.
Objective: To investigate the effect of the severity of AMD in 1 eye on the incidence, progression, and regression of AMD in the fellow eye.
Design, Setting, and Participants: The Beaver Dam Eye Study is a longitudinal population-based study of age-related eye diseases conducted in the city and township of Beaver Dam, Wisconsin. Examinations were performed every 5 years over a 20-year period (from the baseline examination in 1988-1990 to 2008-2010). Study participants (4,379) were 43 to 86 years of age at the baseline examination. At baseline and in up to four subsequent examinations, retinal photographs were taken.
[Note: A longitudinal study follows, and gathers information about, the same individuals or group of people over an extended period of time – often many decades.]
Results: More severe AMD in 1 eye was associated with increased incidence of AMD and accelerated progression in its fellow eye. Less severe AMD in 1 eye was associated with less progression of AMD in its fellow eye. We estimate that 51% of participants who develop any AMD always maintain AMD severity states within 1 step of each other between eyes; 90% of participants stay within 2 steps.
Conclusions and Relevance: Using multistate models, we show that AMD severity in 1 eye tracks AMD severity in its fellow eye.