Posterior segment of eyeball

{{Short description|Back two-thirds of the eye}}

{{Infobox anatomy

| Name = Posterior segment

| Latin = segmentum posterius bulbi oculi

| Image = Schematic diagram of the human eye en.svg

| Caption = Schematic diagram of the human eye

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The posterior segment or posterior cavity{{Cite journal |date=29 August 2014 |title=Medical gallery of Blausen Medical 2014 |url=https://en.wikiversity.org/wiki/WikiJournal_of_Medicine/Medical_gallery_of_Blausen_Medical_2014 |journal=WikiJournal of Medicine |volume=1 |issue=2 |doi=10.15347/WJM/2014.010 |doi-access=free}} is the back two-thirds of the eye that includes the anterior hyaloid membrane and all of the optical structures behind it: the vitreous humor, retina, choroid, and optic nerve.[http://www.e-sunbear.com/anatomy_04.html Posterior segment anatomy] {{webarchive|url=https://web.archive.org/web/20080928144308/http://www.e-sunbear.com/anatomy_04.html |date=2008-09-28 }} The portion of the posterior segment visible during ophthalmoscopy (or fundoscopy) is sometimes referred to as the posterior pole, or fundus. Some ophthalmologists specialize in the treatment and management of posterior segment disorders and diseases.[http://www.neec.com/pages/Vitreoretinal_Disease.html Vitreoretinal Disease & Surgery - New England Eye Center]

In some animals, the retina contains a reflective layer (the tapetum lucidum) which increases the amount of light each photosensitive cell perceives, reflecting the light out of the eye, allowing the animal to see better under low light conditions.