The Persian Traditional Medicine (PTM) system pays special attention to disease prevention. In PTM, physicians believe that overeating may cause accumulation of unhealthy substances in the body and diseases called "Emtela." With respect to ocular health, foods can be categorized as beneficial and harmful. Harmful foods such as beef, geese, eggplant, cauliflower, and cheese can cause reduced vision. Dehydrating foods such as walnut and salty fish and hot foods such as garlic, onion, and pepper can cause dry eye. Food items that have beneficial effects on ocular health include thyme and saffron and fruits such as grape, fig, apple, plum, and berries. PTM stipulates that one should not drink water with meals or immediately afterwards, since drinking cold (icy) water causes difficulty in absorption of nutrients. Gulping water may have harmful effects on the eyes; therefore, PTM physicians recommend drinking water at a suitable temperature. It is not safe to drink water first at the morning. Sleeping right after eating is harmful too. Avicenna believes that sleeping on one's belly after a full meal is very harmful for the eyes. Galen says that old people need deep and continuous sleep more than others. From the view of PTM, moving eyes in different directions, making delicate expressions, trying to look at delicate and find pictures and reading small letters would remove ocular fatigue. There have been mentions of local medicine for improving vision as well; for instance, fennel extracts, pomegranate juice, and honey which are suitable for vision improvement. Local administration of pomegranate blossoms is suitable for treating inflammatory reactions.