The ''pars plana'' (also known as ''orbicularis ciliaris''
) (Latin: flat portion) is part of the
ciliary body
The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. The aqueous humor is produced in the non-pigmented portion of the ciliar ...
in the
uvea (or vascular tunic), the middle layer of the three layers that comprise the
eye.
It is about 4 mm long, located near the junction of the
iris and
sclera
The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some crucial elastic fiber. In humans, and so ...
, and is scalloped in appearance.
The ''pars plana'' may not have a function in the post-
fetal
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal develo ...
period, making this a good site of entry for
ophthalmic surgery of the
posterior segment of eyeball
The posterior segment or posterior cavity 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.[pars plana vitrectomy
Vitrectomy is a surgery to remove some or all of the vitreous humor from the eye.
Anterior vitrectomy entails removing small portions of the vitreous humor from the front structures of the eye—often because these are tangled in an intraocular l ...]
.
References
Human eye anatomy
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