Seasonal influence in wet AMD

The onset of wet AMD occurs more often during the winter months than during the summer months, according to a study published in the February 2011 edition of Acta Ophthalmologica. Patients with new onset wet AMD attending a retina clinic between July 2006 and June 2008 were identified. A total of 366 patients were included in the analysis. 160 patients (44%) presented during summer months (May-October), while 206 patients (56%) presented during winter months (November-April). The difference between the two groups was statistically significant. The researchers identified a number of reasons why wet AMD may have a higher incidence in the winter months. Cardiovascular disease and hypertension are risk factors for AMD, and both have a seasonal variation with a peak in winter months. A second possible reason relates to sunlight. The relationship between light and AMD remains controversial. If sunlight is a trigger for AMD, why was there a higher incidence in winter? This may be because of a time lag between retinal damage and the development of symptomatic wet AMD.