These types of foods - carbohydrates with a high glycaemic index - can cause age-related macular degeneration, a common problem among older people.
People whose diets are high in processed foods are much more likely to develop AMD, researchers from Tufts University, near Boston, have discovered.
High-glycaemic foods cause a faster rise and fall in blood sugar levels, and they have previously been associated with an increased risk of diabetes.
The Tufts researchers analysed data on 4,099 people who were participating in an eye-health study. They estimate that up to 20 per cent of cases of AMD could have been prevented had the patients eaten far less processed foods.
Even a simple dietary change of replacing white bread with whole grain bread could have reduced the risk.
AMD typically occurs after middle age, and it is a leading cause of irreversible blindness.
(Source: American Journal of Clinical Nutrition, 2007; 86: 180-8).