It's not that easy to have big eyes!

A new research has found that large eyes are developed on the stake of other body organ systems and between 5 percent and 15 percent of total energy is required to build big eyes in an infant.

The research led by Sweden's Lund University examined a Mexican cavefish, which lost its visual system through regression, and calculated the actual cost of well-developed vision in animals.

The team of researchers observed that the fish, which lives in a very dark, nutrient-poor environment and has no use for eyes, was clearly different to the surface-dwelling variant, known as a morph, of the same species.

Eric Warrant, one of the researchers, explained that animals with large and well-developed eyes, for their survival pays a high price, as all animals have a strictly limited energy budget, a major investment in the visual system only occurs at a cost to other organ systems.

The research is published in the Science Advances journal.