Changes

They are usually present. The lower lid is movable, moving upwards to close the eye; in some lizards, this lid might be transparent, allowing vision even when the lids are closed. Lizard also have a well developed, semi-transparent, highly mobile third eyelid which is called the 'nictitating membrane'; this membrane can close across the eye even while the eyelids remain open.

They are usually present. The lower lid is movable, moving upwards to close the eye; in some lizards, this lid might be transparent, allowing vision even when the lids are closed. Lizard also have a well developed, semi-transparent, highly mobile third eyelid which is called the 'nictitating membrane'; this membrane can close across the eye even while the eyelids remain open.

In some chameleon species as well as some geckos and the oscellated skink (''Ablepharus sp.'') the eyelids have fused to produce a circular, immobile and transparent dermal aperture called a spectacle. It create an impervious barrier to topically applied medications.  

In some [[Chameleon|chameleon]] species as well as some geckos and the oscellated skink (''Ablepharus sp.'') the eyelids have fused to produce a circular, immobile and transparent dermal aperture called a spectacle. It create an impervious barrier to topically applied medications.

==The pupil==

==The pupil==