CONES AND RODS
The light sensitive cell-receptors of the retina are of two types: Rods and Cones. The centre of the retina is called the fovea and the receptors in this area are all cones. Moving outwards, the cones become less dense and are gradually replaced by rods - in the periphery there are no cones.
- CONES. used for direct vision and are colour-sensitive;
- RODS. the maximum density of rods is found about 10º from the fovea - rods are responsible for our peripheral vision. The rods can only detect black and white but are much more sensitive at lower llight levels. As light decreases, the sensing task is passed over from the cones to the rods.
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