In an eight year study of 3,977 people, those who ate the most carbohydrates with a high glycemic index (a measurement of how quickly a food booosts blood sugar levels) - such as cake, cookies and white bread - had a 40% higher risk for macular degeneration (a retinal disease that destroys central vision) than those who ate the least. Theory: such foods cause cellular damage to the retina (the light-sensitive membrane in the back of the eye)
source - "Bottom Line Health" magazine