The study, published in the Archives of Ophthalmology, determined smokers had a 47 percent increase in their odds of developing early age-related macular degeneration, known as AMD. Smokers also develop AMD at a younger age -- 69.2 years -- than former smokers -- 72.3 years -- and those who had never smoked --74.4 years.

Dr. Ronald Klein and colleagues at the University of Wisconsin School of Medicine and Public Health in Madison studied 4,926 residents of Beaver Dam, Wis., who were between ages 43 to 84 when initially examined in 1988 to 1990. Their eyes were re-examined every five years for the next 15 years. The presence and status of AMD was measured with photographs of the retina.

"While controlling for other factors, smoking appears to be related to the incidence and progression of AMD in our population," the study authors said in a statement. "This has important health care implications, because early AMD is associated with an increase in the risk of developing late AMD and smoking behavior is modifiable."