Recent research has advised people to eat more oily fish to keep their eyesight good and healthy into old age.
The study - coordinated by the London School of Hygiene and Tropical Medicine, looked at the diets of 2,000 people across Europe.
It concluded that those who ate oily fish once a week were half as likely to develop wet age-related macular degeneration (AMD) - a major cause of blindness in the developed world.
Professor Astrid Fletcher said patterns for good health should be laid down as early as possible.
"Most of the studies that have been done in this area have not seen any significant benefit in eating less than one portion of fish a week," she added.
The components in oily fish thought to stave off the effects of wet age-related AMD is DHA - known as docasahexaenoic acid - and EPA - eicosapentaenoic acid.
The macular is the small area at the centre of the retina.
by Alexa Kaczka