J

O Fig. 2.7.4 The management flowchart for eyes with traumatic cataract. Y yes, N no

Lens touch during vitrectomy is a rare complication. The risk is higher if anterior PVR or retinal detachment is the indication because a judicious anterior vitrectomy is one of the goals of surgery. Paradoxically, wide-angle viewing systems have increased the risk since they make it more difficult to visualize the posterior capsule.

T Pearl

Injecting a small air bubble into the anterior vitreous helps identify the plane of the posterior capsule and reduce the risk of lens touch.

If lens touch has occurred, the surgeon should not panic: unless the capsule is actually broken, cataract formation is not inevitable. If, however, major lens opacity does develop intraoperatively and interferes with visualization, cataract extraction must be performed to allow completion of the vitrectomy and unhindered postoperative viewing of the retina. Lens "feathering" is described in Chap. 2.9.

2.7.3.6 IOL 2.7.3.6.1 Implantation

There are several methods to restore the eye's lost refractive power after cataract extraction.30 Of these methods, the IOL is the one that is most convenient for the patient, although it has its own disadvantages.3i Details of

30 Prescription glasses, contact lens, epikeratophakia

31 e.g., the optimal power is difficult to determine in children whose eye is still growing (see Chap. 2.16), and implantation represents additional trauma to the eye, especially if the IOL needs to be sutured into the sulcus

IOL implantation are beyond the scope of this book; only a few important issues are discussed briefly here:

• Timing. Whether primary [11, 13] or secondary [6] implantation should be performed remains a controversial issue. Primary implantation is important for a child in the amblyopic age, or if the patient is unable to afford a second procedure or return for one. Primary implantation causes increased postoperative inflammation and may interfere with subsequent retinal procedures due to visibility issues.32 A careful individual decision must be made, but as a general rule, secondary implantation is recommended.

TCave

Primary IOL implantation should not be performed if the eye has a serious retinal injury or if the risk of PVR is high (see Chap. 2.9).

• Type of implant. Ideally, the IOL is placed in the bag; however, if this is not possible for the lack of adequate capsular support, the lens can be placed in the AC [20], fixated to the iris [22], or sutured into the sul-cus.

• Material of the implant. Silicone IOLs should to be avoided, especially if posterior segment surgery with silicone oil use is expected; the oil may adhere to the IOL surface, making its removal very difficult [19].

- One method to deal with silicone oil that is coating the IOL's surface is to grab a small piece of cotton33 with a vitrectomy forceps, and wipe the IOL's surface with it. The oil cannot be removed completely, but it can be pushed toward the IOL's periphery to reduce its interference with the patient's vision.

- If the zonules are weakened, use of a capsular tension ring may be considered; however, in a trauma case there are several unknowns,

32 The IOL's edge can be disturbing; opacification of the capsule is another issue to consider.

33 e.g., torn from a cotton-tipped applicator and late, "unexplained" luxation of the IOL or even of the capsular tension ring itself may occur [9] if the zonules are weaker than expected.

2.7.3.6.2 Trauma to the IOL Already in Situ

Subluxation is usually treatable by simple repositioning; often it is only the haptic that is partially dislodged. If one of the scleral-fixated IOL's haptics is loose because its suture is broken, the intravitreally hanging haptic can be resutured using a simple technique.

• Prepare a scleral bed in the area where the IOL haptic needs to be fixated.

• Introduce a long, straight intracameral needle (see Chap. 2.6) 1 mm from the limbus through the scleral bed; the needle must be passed behind the haptic and in front of the optic of the IOL, and then partially34 out of the AC on the other side.

• A 27-g hypodermic needle is passed into the AC 1 mm from the limbus through the scleral bed at some distance from the suture. This needle is passed in front of the haptic and optic of the IOL.

• The straight needle is pushed back into the barrel of the 27-g needle. The polypropylene suture is now looped around the free-hanging hap-tic.

• The 27-g needle is withdrawn from the eye, bringing the suture with it: the suture can now be tied, trimmed, and the scleral flap reattached.

Luxation into the vitreous may involve only the IOL or the IOL may still be inside the capsule (Fig. 2.7.5). The IOL luxation does not itself represent a major complication: erosion of the retina is unlikely, but vision is compromised because of the lost IOL power and because of the presence of a large floating object inside the vitreous cavity.

34 The suture end of the needle remains in the AC, only about a half of the needle is externalized.

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