Endoscopy of the ciliary body reveals anatomic details

Whether viewed from front or back, the ciliary processes are the point of reference for identifying surrounding structures.

Issue: June 1, 2000

ByJoseph A. Leon, MD

ByClaude S. Leon, MD

Anatomic endoscopy of the ciliary body performed during a surgical procedure may enhance the surgeon’s ability to employ diagnostic and therapeutic in vivo applications to this intraocular region as it is revealed by the endoscope.

The ciliary body appears as the key feature of reference, as soon as the endoscopic probe illuminates the periphery of the posterior chamber. No doubt that is because of the protruding aspect of the ciliary processes emerging from the base of the ciliary plane. It is in relationship to these ciliary appendices that we define the other fundamental structures of this area – the base of the iris, the irido-ciliary angle, the zonules, the crystalline equator, the pars plana and so on.

Observation of the ciliary body can be approached from either the anterior or posterior direction after insertion of the endoscopic probe.

With the anterior route, whether through a corneal or corneoscleral entrance, the endoscope is advanced across the iris and through the pupil to observe the ciliary processes (Figure 1). Simply turning the objective of the endoscope posteriorly illuminates the posterior chamber cavity and angular borders.

With the posterior approach, through the pars plana, the processes can be viewed from behind. The cilio-retinal junction as well as the posterior capsule and equatorial area of the crystalline lens can be observed.

Seeing the ciliary body

The ciliary body can be described from different angles of observation. The ciliary processes show three sides (anterior, posterior, lateral), a summit and a base. The external base corresponds to the extension of the stroma of the ciliary body toward each process.

The anterior side. This is at an abrupt angle from the summit to the base of the process. It is situated at the irido-ciliary junction (the ciliary sulcus or irido-ciliary groove), and defines a junction line between the intermediate and anterior uvea. More than its appearance as a groove, it can be distinguished by a color change. It is a transition zone, with more pigmentation anteriorly than on the posterior side, between the epithelial structures of the process and those of the posterior iris.

The irido-ciliary junction is not always visible, hidden sometimes by the bulging of the process. It should not be confused with the projected shadow of the process. Another image can cause confusion: the cyclodialysis, more regular and spread out. The anterior side has an average height of about 1 mm, and an approximate width of 0.2 mm to 0.5 mm. These parameters vary depending on the secreting or accommodating activities of the process and under varied intraoperative circumstances.

The posterior side. This has a gentler angle, undulating from the summit of the process to the limit of the ciliary junction between the corona and the orbiculus ciliaris. This junction is made at an obtuse angle. It appears often delimited by a line with doubled outline corresponding to a zonular-hyaloidal bundle that rests on this side of the ciliary epithelium. It is irregular with epithelial winding of the processes.

White atrophic areas are apparent; through them the ciliary capillaries are visible. The junction line between the ciliary crown and the pars plana is indicated by a change in color between the two regions; the orbiculus ciliaris for the most part is darker, a dark brown. Beyond that, the pars plana is a flat zone without folds.

The lateral side. This includes the crevasses of the ciliary valleys. At the back of the valley, the epithelium is much closer to the peripheral side (external). The width of the valley seems to be inferior to that of the process if we compare the back of the valley at the head of the process. The lateral side of the ciliary process is, in general, masked by epithelial folds closed from behind by the anterior circular orbiculary ligament (ligament of Salzmann), and covered by the anterior orbiculo-capsulary fibers.

The head or anterior extremity of the process. This is an area that opens at the joining of the anterior, posterior and lateral sides. This zone of the process is the most prominent and the closest to the equator of the crystalline lens (Figure 2). Protruding radially, the head of the process is the furthest from the ciliary body, pointing toward the central axis of the globe. It corresponds to a dilation, an enlargement of the process. This trait sometimes precludes clear observation of the anterior side and of the irido-ciliary junction.

This head is an essential feature, because its anterior and posterior limits are capped by the zonular fibers, and is important to distinguish. Its posterior area shows the uniqueness of being doubled with the anterior orbiculo-ciliary ligament, a true mark of the hyaloido-ciliary plane. The posterior zonular fibers (long or short) piled in a side plane (posterior orbiculo-capsular plane and Salzmann ligament) will always be perfectly visible: linear condensation.

A remarkable endoscopic sign identifies the Salzmann ligament (Figure 3), which can be described as a “tightrope line” (Endoscopic tight rope line, Leon and Leon, 1985) aligned with the head of the process. The process can be compared with a tightrope walker. The “crest line” of the head of the processes lines up perfectly with the equator of the crystalline lens. The endoscopic view and diagram allow for a better identification of these structures.

The object of endoscopy is to reveal one of the last intraocular areas still unexplored, with macroscopic and microscopic data. This surgical innovation permits direct action on the ciliary body, directly under the control of endoscopy, and it still holds quite a few surprises, not only in cataract surgery, but also equally in the fields of glaucoma and vitreoretinal surgery.

Endoscopic view of the ciliary body through the crystalline lens capsule during cataract surgery: heads of four processes (the tops of the processes) are more visible when the lens equator is cleaned.

Endoscopic plane of reference of the ciliary crown. Ideally, the lens equator is in the same plane (D) as the top of the ciliary body.

Endoscopic signs of fiber densification: anterior and posterior orbiculo-capsular fibers, orbiculo-ciliary ligament of Salzmann, endoscopic tightrope line. The ciliary process can be compared with a tightrope walker.

For Your Information:

Claude S. Leon, MD is president of the International Society of Ophthalmic Endoscopy Inc. in New York. He can be reached at Ocular Endoscopic Surgery, Avenue George Pompidou, Porto-Vecchio, 20137, France; fax: (33) 4-95-70-62-93; email: endo.leon@wanado.fr. Joseph A. Leon, MD, under a European laser certification, is working in all ophthalmic applications of laser endoscopy; email: leon.joseph.opht.endoscop@wanado.fr. The Drs. Leon have a direct financial interest in the endomicroscope (endoscopy under operating microscope) and endoscopic instruments. The Drs. Leon would like to thank the scientific endoscopic collaborators for their help with this article: Daniele S. Aron-Rosa, MD, PhD (France); Yale L. Fisher, MD (USA); Karen M. Joos, MD, PhD (USA); Frank H. Koch, MD (Germany); and Bruce M. Massaro, MD (USA).