When something possesses the quality of chirality it means that has
an orientation or a handedness. This 'Handedness' can be looked upon as
a spin direction or Angular direction. In the northern hemisphere an atmospheric
high pressure zone has clockwise chirality and in the southern hemisphere
high pressure zones are preferentially anti-clockwise. It also manifests
itself in people as a preference for a hand or foot, Thus to be 'right
handed' is to have right handed chirality. There are as far as I know only
two types of chirality ie: left and right however this does not preclude
the possibility for a third or fourth type of chiral behaviour. This would
in effect require the inclusion of extra dimensions.
The Fovea is the centre of vision, the area which we use to focus on
an image. It consists of densly packed retinal cells called cones which
are responsive to coloured light.