A diet high in sugar and starch may make the eyes more vulnerable to age-related macular degeneration (AMD), the most common cause of vision loss in the US. A new study in the American Journal of Clinical Nutrition tracked dietary information from over 4,000 participants aged 55-80 or 8,0000 eyes which, as some participants developed AMD in one eye and not the other, is how they were tracked. The participants completed dietary surveys and had their eyes checked for AMD. The surveys listed over 90 foods, and asked how often they were eaten. The researchers were particularly interested in foods that had a high glycimic index, like sugar and white flour.
The researchers found 600 eyes which did have advanced AMD. Those participants who had a diet high on the glycimic index were most likely to have at least one eye with AMD. This held to be true even when the researchers factored in age, gender, and other risk factors.
The study doesn't show diet to be a sole cause of AMD, and it doesn't track participants over time, so it's unknown what changes in diet would produce. However it adds further encouragement to have a diet high in fiber and whole gains, and lower in sugars and bleached flour.