Glaucoma Week Series 2011- episode 3 (The anatomy of the ciliary body)

Optom
 The Ciliary Body is a complete ring tissue that runs around the inside of the anterior sclera. It measures about 6 mm wide ( slightly wider temporally than nasally).  Anteriorly, the ciliary body extends to the sleral spur (This acts as an attacchment for the ciliary body ventrally. On the posterior side, the ciliary body continues into the ora serrata of the retina.
The ciliary body is divided into the anterior 'pars plicata' which is ridged  and give rise to the ciliary process on which the crystalline lens zonule suspensory ligament anastomose. And the posterior 'pars plana' is smooth and flat which extends into the ora serrata and the choroid. @ the margin between the ora serrata and the ciliary body, the 'pars plana' is modified into a scalloped edge that fits into and corresponds with the tooth-like edge of the ora serrata of the neural part of the retina.
Structurally speaking, the ciliary body is made up of (1) The ciliary epithelium, (2) The ciliary stroma, and  (3) The ciliary muscle.
The ciliary epithelium is that outermost part of the ciliary body that cover the inner surface of the cilliary body. It is made of two layers of pigmented and non-pigmented epithelial cells with their apices juxtaposing. Their basement membrances lies paralel with each other. These arrengement is unique and unlike in other epithelial cell which justifies the diferences in the content of blood plasma and  aqueous humor! The ciliary epithelium forms the blood-aqueous barrier which plays a significant role in Intra-ocular pressure (IOP) maintainance.
The ciliary stroma is a bundle of loose connective tissue, rich in blood vessels and melanocytes. The loose connective tissue in the stroma forms a connective tissue core with the ciliary process. The stroma also provides attachment for the ciliary muscles which functions in crystaline lens accomodation.
 The ciliary muscle is innervated by the posganglionic parasympathetic fibres derived from the oculo-motor nerves, via the short cilliary nerves. They form the bulk of the ciliary body and consists of smooth muscle fibres.

Finally,the aim of this detailed discription of the ciliary body is to identify the role it plays in production of aqueous humor and the regulation of IOP in the eye. The eye is regarded as a leaking system for aqueous humor, from the ciliary body to the collector channels and aqueous veins of the Sinus venosus sclerae (canal of Schlem); or the episcleral spaces. It is on record that the rate of aqueous humor formation is approximately 2.4+/-0.6 ul/min (Micro-liter per minute).
To be continued...

Dr Ezebuiroh Okwudiri Victor.