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*'''Cornea''' - The pupil is commonly elliptical or round and may give an indication of habitat and lifestyle. Often diurnal species have round pupils and nocturnal species have vertical pupils. Coral snakes and all New World non-venomous snakes, except the boa constrictor have round pupils, while pit vipers have vertical slit pupils.
*'''Cornea''' - The pupil is commonly elliptical or round and may give an indication of habitat and lifestyle. Often diurnal species have round pupils and nocturnal species have vertical pupils. Coral snakes and all New World non-venomous snakes, except the boa constrictor have round pupils, while pit vipers have vertical slit pupils.
*'''Sclera''' - The eye has no ossicles (unlike other reptiles) and the sclera is composed entirely of tendinous connective tissue.
*'''Sclera''' - The eye has no ossicles (unlike other reptiles) and the sclera is composed entirely of tendinous connective tissue.
*'''Posterior segment''' - The retina is usually grey mottled with white or red spots and appears with semi-opaque nerve fibres radiating uniformly outwards from the optic disc that is obscured in families having a conus. It is avascular and the membrana vasculosa retinae supply nutrients.[[Category:Snake Anatomy]]
*'''Posterior segment''' - The retina is usually grey mottled with white or red spots and appears with semi-opaque nerve fibres radiating uniformly outwards from the optic disc that is obscured in families having a conus. It is avascular and the membrana vasculosa retinae supply nutrients.
==Physiology==
Accommodation is similar to mammals with changes in the shape of the lens. Unlike mammals, this is under voluntary control by the action of the striated radial muscles within the ciliary body. Mammalian mydriatics therefore do not work in reptiles. However, d-tubocurarine has been used for mydriasis in reptiles. The injection of 0.05 to 0.1ml via a 27-30g needle into the anterior chamber results in mydriasis for 30 minutes to several hours. Reptiles have a rapid direct light reflex but no consensual light reflex.
[[Category:Snake Anatomy]]