Ординатура / Офтальмология / Английские материалы / Ocular Traumatology_Kuhn_2008

1 Typically at 90−180° from the wound if it is limbal; if the wound is more toward the central cornea, the primary factor in determining the paracentesis location is convenience for the surgeon.

2  Cosmesis may be another indication if the synechia is large; the patient must understand the risks of the procedure before the surgeon consents to the patient’s wish.

3  i.e., an iris bombans is present

4  i.e., short-acting dilatation is to be used, not atropin; a wide pupil may have to be constricted even though this risks increasing the inflammation

2.5.3.6Comprehensive Anterior Segment Reconstruction

Several structures of the AC and adjacent tissues may be damaged during the injury, and posttraumatic scarring may make the condition worse. The scar tissue can destroy the cornea and the angle, elevate the IOP, and seriously impede vision (Fig. 2.5.4). Reconstruction of such eyes requires a surgeon skilled in both anterior and posterior segment techniques, ranging from PK to vitrectomy. Chapters 2.1−2.15 and 2.18−2.20 describe various elements of the intervention, which must also be carefully planned.25

25The reconstruction is typically done as a late procedure, the details of which are beyond the scope of this book.

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Fig. 2.5.4  Comprehensive anterior segment reconstruction. The patient had bilateral injuries several years ago; multiple surgeries (repeat PK, lens removal, IOL implantation, repeat vitrectomies) have been performed, but visual acuity is LP in both eyes and the IOP is under 8 mmHg. The two eyes look virtually identical. a Preoperative image of the right eye. The graft is clear but the peripheral cornea has multiple layers of new vessels. There is a large, vascularized retrocorneal membrane. The iris is barely visible; even its color is difficult to determine. b Postoperative image of the left eye. Most of the corneal vessels have been closed. The retrocorneal membrane has been removed. The angle has been freed. The IOL has been respositioned. The vitreous cavity has been lavaged. Visual acuity improved to 20/160, the IOP is 16 mmHg

2.5.3.7Angle Recession

A condition that often leads to glaucoma, angle recession is discussed in Chap. 2.18.

DO:

•determine whether sickle cell disease has played a role in hyphema development

•prevent corneal blood staining by aggressively bringing the IOP down and by removing the intracameral blood early if staining threatens

•learn the basics of viscoelastic properties and use to maximize their benefits and reduce the risks of their use

DON’T:

•start hyphema removal before planning all aspects of surgery including timing, instrumentation, and wound preparation

•forget that damage to other intraocular structures are very common in eyes with hyphema

•leave vitreous incarcerated into a corneal wound

Summary

The AC has a wide variety of pathologies; in addition to knowing how to deal with each, the surgeon should also learn some basic rules such as

space and tissue tactics. Of the major pathologies, hemorrhage has the greatest importance.

References

[1]Beyer TL, Hirst LW (1985) Corneal blood staining at low pressures. Arch Ophthalmol 103: 654−655

[2]Bhargava S, Chopdar A (1971) Gas gangrene panophthalmitis. Br J Ophthalmol 55: 136−138

[3]Edwards W, Layden W (1973) Traumatic hyphema. Am J Ophthalmol 75: 110−116

[4]Erol N, Ozer A, Topbas S, Yildirim N, Yurdakul S (2003) Treatment of intracameral fibrinous membranes with tissue plasminogen activator. Ophthalmic Surg Lasers Imaging 34: 451−456

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[5]Katz J, Feldman MA, Bass EB, Lubomski LH, Tielsch JM, Petty BG, Fleisher LA, Schein OD (2003) Risks and benefits of anticoagulant and antiplatelet medication use before cataract surgery. Ophthalmology 110: 1784−1788

[6]Mandell MA, Pavlin CJ, Weisbrod DJ, Simpson ER (2003) Anterior chamber depth in plateau iris syndrome and pupillary block as measured by ultrasound biomicroscopy. Am J Ophthalmol 136: 900−903

[7]Ozdal MP, Mansour M, Deschenes J (2003) Ultrasound biomicroscopic evaluation of the traumatized eyes. Eye 17: 467−472

[8]Park S, Marcus D, Duker J, Pesavento R, Topping P, Frederick A, D’Amico D (1995) Posterior segment complications after vitrectomy for macular hole. Ophthalmology 102: 775−781

[9]Parrish R, Bernardino V Jr (1982) Iridectomy in the surgical management of eightball hyphema. Arch Ophthalmol 100: 435−437

[10]Pieramici DJ, Goldberg MF, Melia M, Fekrat S, Bradford CA, Faulkner A, Juzych M, Parker JS, McLeod SD, Rosen R, Santander SH (2003) A phase III, multicenter, randomized, placebo-controlled clinical trial of topical aminocaproic acid (Caprogel) in the management of traumatic hyphema. Ophthalmology 110: 2106−2112

[11]Sholiton DB, Solomon OD (1981) Surgical management of black ball hyphema with sodium hyaluronate. Ophthalmic Surg 12: 820−822

[12]Striph G, Halperin L, Stevens J, Chu F (1988) Afferent pupillary defect caused by hyphema. Am J Ophthalmol 106:

[13]Walton W, Hagen S von, Grigorian R, Zarbin M (2002) Management of traumatic hyphema. Surg Ophthalmol 47: 297−334

[14]Weissman JL, Beatty RL, Hirsch WL, Curtin HD (1995) Enlarged anterior chamber: CT finding of a ruptured globe. Am J Neuroradiol 16: 936−938

  2.6  Iris and Pupil

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2.6.1Introduction

The two most important attributes of the iris are its regulatory function, controlling the amount of light reaching the retina, and its barrier function, separating the two main chambers of the eye. In addition, the iris has a cosmetic function, whose significance should not be underestimated. Restoration of the injured iris to its normal anatomy is one of the most neglected aspects of ocular traumatology.

The presence of major iris damage is an indicator of ciliary body trauma: if traumatic aniridia is found, the risk of eventual phthisis increases.

2.6.2Evaluation

Major abnormalities are easily seen with the naked eye, especially if the iris is light colored. A penlight is used to compare the injured iris’ color with that of the fellow eye.

Examination of the iris always includes examination of its aperture, the pupil. Dividing the globe into anterior and chambers is especially important in an aphakic or pseudophakic eye filled with silicone oil.

Heterochromia is obviously impossible to diagnose without inspecting the fellow eye. Color difference is much more difficult to notice at the slit lamp since the two eyes cannot be viewed simultaneously.

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Fig. 2.6.1  Transcameral suture for damaged iris sphincter muscle.1 The initial step is to assure that there is no synechia; if there is, this must be broken before suture introduction (see Chap. 2.5). a The iris lesion may involve the pupillary margin or may be more peripheral. b A long, straight or curved needle is used to enter the AC through the cornea at a convenient location but outside the visual axis. The needle enters the torn iris on both sides of the lesion, and exits the cornea on the opposite side (thick arrow). Do not enter/exit the AC in the limbus; it is easier to catch the suture later during the procedure if the suture is in an area with greater AC depth. Once the suture has been pulled through, the needle is cut off. c A paracentesis is made somewhere in the middle plane between the two needle entry/exit points, over the iris lesion (arrow). As described in Chap. 2.5, the angle of the paracentesis must allow easy maneuvering as well as watertightness without suture. The paracentesis should not be far away from where the knot will be (see below). d A hook fashioned at the tip of a hypodermic needle or a vitrectomy forceps is used to engage the two sutures above the iris and pull them out from the AC through the paracentesis. e The sutures are tightened. The iris must be sufficiently loose because it will be tented as the suture is tightened. This is the reason why the paracentesis must be strategically placed, and placed after, and not before, the sutures are introduced into the iris. If the iris is rigid or the lesion is wide, intraocular suture tightening may have to be performed or the lesion is treated only partially.2 Internal tightening of the knot requires a paracentesis on both sides. The suture enters the AC via one paracentesis, picks up the iris as described above, and exits the AC through the other paracentesis. The suture is then partially withdrawn3 and tied using the loop: the knot is formed inside the AC, without tenting the iris. The needle is then pulled back through both paracenteses and the entire procedure is repeated. An alternative is not to bring the iris edges in apposition but leaving a small gap between them. f The iris is left to slide back in place; the suture remains visible, but the gap in the iris should disappear or become very small. If need be, additional sutures may be introduced in the same way. The procedure can also be performed in a phakic eye, after first carefully injecting cohesive viscoelastics under the iris

1 Viscoelastics are typically not necessary, although the surgeon should apply them if the AC gets shallow.

2  A description of these two techniques are given here, but neither is shown.

3 The needle remains outside the eye.

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Transcameral needles are not easy to use (Fig. 2.6.2). The needle’s path through the cornea acts as a fulcrum; the more forward the needle’s position in the AC is, the smaller a movement with the needle holder is needed to cause in a large movement of the needle’s tip. To make needle use easier, the surgeon should either bring the needle’s entry point as close to its intracameral target as possible, or use another instrument (e.g., a vitrectomy forceps) to guide the needle inside the AC.

ZCave

Any suture placed into the iris must provide a permanent lock: there is no iris healing. The suture material must be nonabsorbable [10/0 or 9/0 polypropylene on a straight (STC-6) or curved (CIF-4) needle] and the knot must be made very secure. The suture must not exert undue tension on the iris to avoid “cheesewiring.”

If the sphincter muscle is completely nonfunctional, an iris cerclage (purse string) suture should be used (Fig. 2.6.3).

2.6.3.2Laceration/Coloboma

Surgery should be considered if the lesion prevents proper pupillary function, visual disturbance , or causes a significant cosmetic problem. The surgical technique is identical to the one described above for sphincter muscle damage (Fig. 2.6.1).

2.6.3.3Iridodialysis

The pathognomic sign of the condition – tearing of the peripheral portion of the iris root from the ciliary spur – appears as a black slit at the limbus.

Ethicon/Johnson & Johnson, New Brunswick, N.J. Every suture mentioned in this chapter is one of the two types described above.

Monocular diplopia, photophobia.

It is usually visible to the naked eye, although the slit lamp is often needed to confirm the diagnosis. If the iridodialysis is large enough, a red reflex is apparent where it should not be (Fig. 2.7.2).