Textbook of Ophthalmology by Sanjeev Kumar Mittal & Raj Kumar Agarwal

Author:Sanjeev Kumar Mittal & Raj Kumar Agarwal [Mittal, Sanjeev Kumar]
Language: eng
Format: epub
Publisher: Thieme Publishers Delhi
Published: 2022-06-27T05:00:00+00:00

Fig. 13.58 Anatomy of ciliary body and ora serrata.

■Ora Serrata

It is the junction between retina and ciliary body. At ora, fusion of sensory retina with RPE and choroid limits forward extension of SRF. However, choroidal detachments may progress anteriorly to involve ciliary body, as there is no such adhesion between choroid and sclera. Externally, ora corresponds to insertions of rectus muscles. So, in emmetropic eye ora is located 7 mm behind limbus temporally and 6 mm behind limbus nasally.

■Vitreo Retinal Traction

It is a force exerted on retina by structures originating in the vitreous. It may be:

•Dynamic traction: It is induced by eye movements. It plays the role in the pathogenesis of retinal breaks (tears) and rhegmatogenous RD.

•Static traction: It is independent of eye movements and it plays a role in the pathogenesis of tractional RD.

■Retinal Breaks

A retinal breaks is a full-thickness defect in the sensory retina. Breaks can be tears or holes. Tears are caused by dynamic vitreoretinal traction. A tear may be:

•Horseshoe-shaped or arrowhead (apex is pulled by vitreous and base remains attached to retina) (Fig. 13.59).

•Dialysis (circumferential tear along ora serrata).

•Giant tear (tear involving more than a quadrant of the circumference of globe).

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