Knowledge about the properties of different types of fats has boomed in recent years, and new research suggests that certain fats may increase or indeed decrease the risk of contracting the eye disease termed age-related macular degeneration (AMD). AMD is an untreatable disease that causes fuzziness, shadows and other loss of clear vision.

Once again it is omega-3 fatty acids that emerge as the apparently healthier fat. A study conducted by the Massachusetts Eye and Ear Infirmary found that individuals with diets rich in omega-3 fatty acids and low in linoleic acid, which is present in corn and safflower oil, had a lower risk of the disease. This contrasted with those who ate foods high in monounsaturated fats, such as olive oil, who had a 71% increased risk of the disease, and those who ate foods rich in polyunsaturated fats, such as margarine, who had an 86% increased risk of the disease.

The study analysed 349 individuals aged between 55 and 80 who had been diagnosed with AMD, as well as 504 who suffered from other eye diseases but not AMD.

Foods with high levels of the fats which emerged as harmful – vegetable fat, monounsaturated and polyunsaturated fats and linoleic acid – tend to be processed, store-bought snack foods, lead researcher Dr Johanna M. Seddon noted. “Eat a good healthy diet,” Seddon advised. “Cut down on processed foods [and] increase fish intake, but everything in moderation.”