Michael D. Knudtson

Background: Cardiovascular disease and age-related macular degeneration (AMD) may share common risk factors. Physical activity improves the cardiovascular risk profile; however, there have been few studies investigating a relationship between physical activity and the long-term incidence of AMD. Methods: The 15-year cumulative incidence of AMD was determined through four examination phases at 5-year intervals of a population-based study conducted in Beaver Dam, Wisconsin, USA, initiated in 1988–90 (n = 3874 men and women between ages 43 and 86 years). Early AMD (pigment abnormalities or soft indistinct drusen), exudative AMD and geographic atrophy were determined by grading stereoscopic colour fundus photographs. Measures of physical activity were obtained through a questionnaire administered at the baseline examination. Results: After controlling for age, sex, history of arthritis, systolic blood pressure, body mass index, smoking and education, people with an active lifestyle (defined as regular activity ⩾3 times/week) at baseline were less likely to develop exudative AMD (odds ratio (OR) 0.3, 95% confidence interval (CI) 0.1 to 0.7) compared with people without an active lifestyle. After multivariate adjustment, increased categories of number of blocks walked per day decreased the risk of exudative AMD (OR 0.7, 95% CI 0.6 to 0.97). Physical activity was not related to the incidence of early AMD or pure geographic atrophy. Conclusions: These data show a protective effect of physical activity for incident exudative AMD, independent of body mass index and other confounders. They also suggest a possible modifiable behaviour that might be protective against developing AMD.

Many studies have investigated associations between ocular disorders and survival.^1-23 In general, persons with ocular disorders have been shown to have an increased mortality risk compared with persons without the disorders. These associations have been shown with cataract,^{1,2,4,6,9,13-16,18-21} glaucoma,⁷ diabetic retinopathy,^8,10,22,23 and visual impairment^{4,9,11,12,17,19} and recently with age-related maculopathy (ARM).^3,4 In many instances, these associations can be explained by controlling for systemic mortality risk factors because ocular disorders are associated with these factors. However, some studies do not show associations with ocular disease and mortality.^2,5,19 Differences in study design, mortality follow-up, and definitions of these ocular conditions may explain some of these inconsistencies. In the present study, we extend a previous study of mortality and eye disease from our group⁹ in the large population-based Beaver Dam Eye Study to 14 years of follow-up.

Research from JAMA Ophthalmology — Age-Related Eye Disease, Quality of Life, and Functional Activity

Purpose. To describe cumulative incidence and changes in retinal lesions associated with age-related maculopathy (ARM) by location over a 10-year period and to examine the relation of location of those lesions to progression of ARM.

Background/aims: To assess the variability in retinal vessel measurements at different points in the pulse cycle. Methods: A healthy white male aged 19 years had 30 digitised images taken at three distinct points in the pulse cycle over a one hour period. A pulse synchronised ear clip trigger device was used to capture images at the desired point in the pulse cycle. Two trained graders measured the retinal vessel diameter of one large arteriole, one large venule, one small arteriole, and one small venule 10 times in each of these 30 images. Results: Within an image, variability was similar between graders, pulse point, and vessel type. Across images taken at the same point in the pulse period, the change from the minimum to maximum measurement was between 6% and 17% for arterioles and between 2% and 11% for venules. In addition, measurements of small vessels had greater changes than large vessels and no point in the pulse period was more variable than another. Ignoring pulse cycle increased variability across images in the large venule, but not in the other vessel types. Mixed effect models were fit for each of the vessel types to determine the greatest source of variability. Controlling for pulse point and grader, the largest source of variability for all four vessels measured was across images, accounting for more than 50% of the total variability. Conclusion: Measurements of large retinal venules is generally less variable than measurements of other retinal vessels. After controlling for pulse point and grader, the largest source of variation is across images. Understanding the components of variability in measuring retinal vessels is important as these techniques are applied in epidemiological studies.