The advantages and capabilities of endoscope use are as follows:
• With endoscopy, the timing of surgery is determined by the condition of the injured tissues, not by the clarity of the media. If visualization of the posterior segment is severely compromised by the corneal damage and vitrectomy is urgent, the surgeon may want to forgo using the TKP (see Chap. 2.15). Endoscopic bypassing of the anterior segment opacities [1, 3] spares the patient of the potential complications of performing PK on an acutely injured eye. If PK becomes necessary subsequently, it can be scheduled so that the risk of transplantation-related intra- and postoperative complications is reduced.
• During EAV, progressive intraoperative opacification of the cornea or lens does not jeopardize surgical success.
• The endoscope helps identify the site for ideal sclerotomy placement, including that for the infusion cannula. The proper position of the cannula's port3 can be confirmed before the infusion is opened.
• Endoscope use allows inspection of intraocular spaces that are impossible or very difficult to view by traditional methods: the posterior surface of the iris; the lens capsules, bag, and the IOL behind the iris; the zonules and capsulozonular complex; and the ciliary body.
• The endoscope makes it unnecessary to employ scleral indentation, regardless of whether it would be used to examine or treat the crucial peripheral structures4. Foregoing scleral indentation means that pathologies, such as ciliary body detachment or vitreoretinal traction, are inspected "in vivo", i.e., without physical distortion. The presence of anterior PVR or cyclitic membranes [2, 3] is not only easier to recognize, but their true effect on the normal tissues can be observed.
3 i.e., is it in front of, rather than underneath, the retina and uvea.
4 i.e., anterior retina, pars plana, ciliary body.
Fig. 2.20.2 Endoscopic peeling of the anterior vitreous base. This eye had an IOFB injury, and the retina was also detached. Endoscopy-assisted vitrectomy was performed 20 days later. Blood, adherent to the pars plana, is being dissected and removed
• With proper technique,5 complete and unhindered intraoperative inspection is achieved, both circumferentially (360° visualization of all anterior structures; see Chap. 2.8) and antero-posteriorly (from the retrolental to the subretinal space). Endoscopy thus has unique significance in eyes whose injuries involve the posterior eye wall (see Chaps. 2.9, 2.14).
- The endoscope is not simply a diagnostic tool: with its high-magnification and high-resolution image and tangential approach it allows performing surgical tasks (e.g., EAV) that would be difficult or impossible to accomplish with traditional viewing techniques. An incomplete list of such tasks includes:
- Dissection of the vitreous base area to remove vitreous, blood (Fig. 2.20.2), proliferative cells, stem cell ingrowth , scar tissue, and cyclitic membranes [2, 3]
- Releasing traction to help reattach the retina, choroid, and ciliary body (Figs. 2.20.3, 2.20.4)
- Complete removal of the vitreous from behind the lens
5 i.e., using multiple sclerotomies in the presence of a clear lens.
- Freeing the iris (see Chap. 2.6) from scar tissue grown over its posterior surface or "unrolling" of a retracted iris 
- Repositioning subluxated or luxated IOLs
Fig. 2.20.3 Endoscopy-assisted vitrectomy revision of the ciliary body area after failure of conventional vitrectomies. A thick cyclitic membrane is adherent to a corneal wound, and there is ciliary detachment. The iris and cornea are visible at the top of the image. The flow is raised up to 14 ml/m to allow grasping of the elastic membrane. Even though complete removal was not possible, the remnants could be dissected from the ciliary epithelium
Fig. 2.20.4 Endoscopy-assisted vitrectomy revision of complex posttraumatic anterior segment pathologies. Tangential, high-magnification view of the peeling of adhesions between the ciliary body and vitreous, which is also incarcerated into the corneal wound. The retracted iris and cornea are visible on the right side of the image
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