Cataract surgery is the most common operation performed in the United States and has one of the highest success rates.1 Phacoemulsification techniques have revolutionized the field of cataract surgery, and have allowed for the development of innovations such as small incisions and foldable intraocular lens implants. More recently, sutureless corneal incision techniques have come into favor, and many cataract operations are done with topical anesthesia, thus eliminating retrobulbar and peribulbar anesthesia and the associated risks.

These remarkable advances in technology have led to equally remarkable refinements in the surgical skills of the ophthalmologist, operations of shorter duration and higher surgical case loads. Expectations of patients have dramatically increased as a result of the rapid visual and physical rehabilitation of what has become a relatively minor operation. Commercial advertising for cataract surgery has fueled this increase in expectations by minimizing the need for injections or patches, reducing postoperative pain, and emphasizing that return to normal activities may be possible within days.

The uncomplicated cataract operation with implant is indeed a minor operation with remarkable outcomes in the vast majority of cases. Although the complication rate is quite low, the consequences can cause significant visual loss. Awareness of these complications and appropriate management can minimize the visual impairment and enhance the outcome and recovery for the patient, thereby reducing the risk of litigation that so often arises when patient expectation is not met.

The posterior segment complications of cataract surgery are not specific to phacoemulsification. This chapter reviews the important clinical features and treatment options, with emphasis on phacoemulsification. Posterior segment complications include retained lens fragments, dislocated intraocular lens implant, endophthalmitis, suprachoroidal hemorrhage, and needle penetration of the globe for anesthesia.

RETAINED LENS FRAGMENTS

The most common clinical situation leading to retained lens fragments in the vitreous is posterior capsular rupture, with loss of lens fragments posteriorly into the vitreous cavity during the fragmentation phase of phacoemulsification. The displaced lens fragment may involve the entire nucleus or any fraction of it. The best estimate of the incidence of posteriorly displaced lens fragments is 0.3%.2 Once posterior capsule rupture occurs, the surgeon must proceed with extreme caution in using a limbal approach to retrieve displaced lens fragments. Although in some instances converting to a larger incision and using a lens loop or forceps will allow retrieval of a nuclear fragment before it migrates posterior to the capsule, once the fragment falls posteriorly a high chance of further complication ensues with limbal retrieval attempts. Some surgeons advocate vigorous attempts at retrieving the lost lens nucleus from the limbal cataract incision by probing posteriorly with a lens loop or other instrumentation, or by using high volumes of infusion fluid to create vortex currents to

float the lens fragment anteriorly.3 However, vigorous attempts at retrieving a posteriorly dislocated nucleus from the limbus with high volumes of intraocular fluid or posterior manipulation of the instrument has been associated with giant retinal tears that have a poor prognosis for visual acuity.4 In a recent case managed by one of the authors, the nucleus was found underneath a giant tear retinal detachment in the inferior nasal quadrant.

CLINICAL FEATURES

Posterior loss of lens fragments is usually recognized intraoperatively after posterior capsular rupture. Occasionally retained lens material may present with chronic intraocular inflammation and no visible fragments in the posterior pole. The degree of intraocular inflammation usually reflects the size of the retained lens fragment, the time interval since cataract surgery, individual inflammatory reactivity, and the extent of previous intraocular manipulations. Associated clinical signs including corneal edema, glaucoma, uveitis, and vitreous opacities. Initially these findings are frequently mild, especially in the immediate postoperative interval, but, over time, may worsen and lead to other complications such as retinal detachment, causing profound visual loss.5,6

SURGICAL INDICATIONS

The size of the lens fragment and severity of intraocular inflammation usually forms the basis for surgical intervention. Operations should probably be performed if the lens nucleus fragment is larger than about 3 mm in diameter because secondary inflammatory complications will virtually always ensue. Eyes with very small retained fragments have a better prognosis and can often be observed indefinitely. However, if inflammation has not subsided by 1 to 2 weeks, surgical intervention should be considered regardless of how small the retained fragment is, because other occult fragments may be harbored behind the iris.

Chronic glaucoma was reported to be more common when the subsequent vitrectomy was performed more than 3 weeks following surgery.7 Other studies have not found any outcome differences between earlier and later intervention.8–11 A study of 126 patients before vitrectomy for posterior chamber lens fragments after phacoemulsification demonstrated a 37% prevalence of intraocular pressure (IOP) above 30 mm Hg preoperatively.8 The IOP normalized in all except 3% of patients after vitrectomy. The patient’s overall clinical situation may influence timing, but usually surgery to remove retained lens

material is performed within 2 weeks of the original cataract surgery to expedite visual rehabilitation, to break the cycle of progressive lens-induced inflammation, and to lessen risks of secondary lens induced glaucoma. These goals may be logistically maximized when lens fragment retrieval and removal can be expertly performed during the original cataract operation. When this is not feasible, a delay of several days or even weeks may be equally effective, because the inflammation, corneal edema, and glaucoma will improve with topical treatment over several days following cataract surgery.

SURGICAL TECHNIQUES

A variety of techniques have been described for use by the anterior segment surgeon at the time of lens fragment loss. Although some cases may be satisfactorily managed through a limbal incision, pars plana vitrectomy techniques probably offer superior results in most cases.7–15 There are three basic surgical techniques for lens fragment removal using a pars plana vitrectomy: (1) ultrasonic fragmentation, (2) mechanical crushing of the nucleus between two instruments, and (3) limbal extraction of hard nuclear fragments. The availability of modern phacofragmentation units generally precludes the need for the latter two techniques, but they are options when fragmentation is unavailable or in cases with an extremely hard nuclear fragment.

There are three key elements in successful lens fragment removal technique. First, adequate initial vitrectomy avoids unintended vitreous traction during phacofragmentation (Fig. 26–1). Second, reducing fragmentation power to only 5 to 10% of maximum allows more efficient nuclear extraction by continuous occlusion of the suction port minimizing the risk of mechanical retinal trauma from projectile fragments. This maneuver also minimizes the chance of fragments dropping back onto the retina even though these fragments rarely strike the retina with sufficient force to damage the retina. Third, fragments should be cautiously aspirated from the retinal surface and moved to the mid-vitreous before activating ultrasonic fragmentation to avoid suction or ultrasonic damage to the retina (Fig. 26–2).

Perfluorocarbon liquids have been described to float the nucleus anteriorly to facilitate removal,16,17 but are most useful when retinal detachment coexists.18 Techniques for reattaching the retina when associated with retained lens fragments are similar to those for other complex retinal detachments.19,20

Most anterior segment surgeons proceed to intraocular lens (IOL) insertion at the time of the origi-

FIGURE 26–1 Attention to complete central vitrectomy allows access to retained lens fragments. (From Regillo CD, Brown GC, Flynn HW Jr. Vitreoretinal Disease: The Essentials. New York: Thieme; 1999:568, Fig. 35–5.)

FIGURE 26–2 Low ultrasonic fragmentation power allows more controlled removal of fragments. (From Regillo CD, Brown GC, Flynn HW Jr. Vitreoretinal Disease: The Essentials. New York: Thieme; 1999:569, Fig. 35–6.)

nal cataract surgery, as is recommended by the majority of vitreous surgeons in spite of the intraoperative complication of posteriorly displaced lens fragments. If there is sufficient capsular support, the IOL is placed in the posterior chamber (PC). If not, suture fixation techniques may be used 21–32 or an anterior chamber (AC) IOL may be placed. If the cataract surgeon is reluctant to insert the IOL primarily, it can be inserted at the time of the subsequent vitrectomy.

OUTCOMES OF VITRECTOMY FOR

RETAINED LENS FRAGMENTS

The visual results of managing such cases are generally good.7–16 Postoperative visual acuity of 20/40 has been achieved in the majority of patients in many series. One series reported only a 41% rate of 20/60,7 but recent series report 60 to 82% rates of 20/40.8–15 This apparent improvement may reflect changing patterns of cataract surgery technique because a poorer prognosis has been suggested with dropped lens nuclei when extracapsular cataract extraction (ECCE) techniques are used compared to phacoemulsification extraction methods.7

Postoperative complications related to vitrectomy surgery may be difficult to differentiate from those attributable to complicated cataract surgery, and may include corneal edema, glaucoma, persistent intraocular inflammation, and new retinal detachment.33 Retinal detachment coexisted with retained lens material in 8.0% of reported series and retinal detachment has been reported after vitrectomy for removal of retained lens fragments in 8.3% of reported series (Table 26–1). Thus, it is of critical importance to evaluate the retina throughout the perioperative course in such patients. One author suggested prophylactic scleral buckle in cases undergoing vitrectomy for retained lens fragments,34 but this entails needless surgery (and its incumbent complications) in 90% of eyes.

RECOMMENDATIONS FOR

MANAGEMENT OF RETAINED

LENS FRAGMENTS

Recommendations to the anterior segment surgeon experiencing the complication of posterior dislocation of lens fragments include (1) avoid loss of fragments by immediate use of dispersive viscoelastic to trap nuclear fragments; (2) use a Sheets’ glide to stabilize the nucleus in the presence of a large capsular tear; (3) attempt lens fragment retrieval only if fragment is readily accessible; (4) perform anterior vitrectomy as necessary to avoid anterior vitreous prolapse

into the surgical incision; (5) if possible, insert PC IOL using residual posterior capsule or AC IOL, as merited by the situation; (6) close the cataract wound in a standard fashion and remove viscoelastic (sutures are indicated to ensure wound integrity during subsequent vitrectomy); (7) prescribe frequent postoperative topical antiinflammatory treatment and IOPreducing agents; and (8) refer the patient for vitreoretinal consultation within a few days for initial evaluation (Table 26–2). If the opportunity and expertise exists, perform the vitrectomy and retrieval of displaced lens fragments at the same operation.

Recommendations for the vitreoretinal surgeon include (1) initially observe eyes with minimal inflammation and a very small lens fragment; (2) continue or initiate treatment with topical corticosteroids and antiglaucoma agents; (3) intervene surgically if inflammation or IOP is not controlled, or if the fragment is estimated to measure 3 mm; (4) delay surgery as necessary to allow for initial treatment of postoperative inflammation and allow clearing of corneal edema; (5) perform adequate core vitrectomy before attempting phacofragmentation; (6) use low fragmentation power settings (5 to 10%) for more efficient removal of small fragments; (7) be prepared for secondary IOL insertion in aphakic eyes or IOL exchange in some pseudophakic eyes; and (8) exam-

ine peripheral retina for possible retinal tear or detachment (Table 26–3).

INTRAOCULAR LENS DISLOCATION

Postoperative decentration of PC IOLs occurs in 0.2 to 1.2% of cases and usually does not require treatment.35,36 A less common but more significant complication is IOL dislocation into the vitreous cavity. A common element in all cases is insufficient posterior capsule support. This is typically due to posterior capsular rupture during cataract extraction.When dislocation occurs within the first few days or weeks after surgery, the cause may be less apparent and may be the result of unknowingly placing the IOL through a posterior capsular defect onto the anterior hyaloid, or as a result of subsequent IOL haptic rotation out of a zone of residual capsule remnants. Late dislocation is less common and may be due to traumatic37 or spontaneous loss of zonular support such as in eyes with pseudoexfoliation syndrome.

CLINICAL CHARACTERISTICS

Complete dislocation of PC IOLs into the vitreous cavity is typically observed within the first week fol-