Volume 6, Chapter 65. Retained Lens Material

Chapter 65
Retained Lens Material
Robert C. Wang, Dwain G. Fuller and William L. Hutton
Main Menu Table Of Contents

INCIDENCE
IMMUNOPATHOLOGY OF RETAINED LENS MATERIAL
MANAGEMENT BY THE ANTERIOR SEGMENT SURGEON
POSTOPERATIVE EVALUATION
SEQUELAE OF RETAINED LENS FRAGMENTS
UVEITIS
GLAUCOMA
TIMING OF VITREOUS SURGERY
VITRECTOMY TECHNIQUE
RESULTS OF VITRECTOMY
CONCLUSION
REFERENCES

The loss of lens material using extracapsular techniques has become less frequent with modern methods. Phacoemulsifcation with multiple ultrasound settings and various irrigation/aspiration tips has simplified the removal of nuclear and cortical material. In high-risk cases such as pseudoexfoliation syndrome, the additional use of capsular tension rings has made lens extraction in these patients much safer than in the past.

Despite these advances, posterior capsular rupture and lens loss into the vitreous cavity still occur. Multiple complications can result, severely compromising final visual acuity. Corneal edema secondary to high phacoemulsification power and inflammatory glaucoma can impair vision and impede posterior segment evaluation. Loss of endothelial cells can cause permanent corneal edema, necessitating future corneal transplantation. Iris adhesions from secondary inflammation may also occur as can iris capture from sulcus or anteriorly placed intraocular lenses. Frequently, complicated surgery with the loss of lens material posteriorly results in cystoid macular edema. More significantly, vitreoretinal traction from disruption of the posterior capsule with vitreous presenting into the anterior chamber can result in retinal tears and detachments, which may lead to significant visual loss.

INCIDENCE

Extracapsular surgery, specifically modern phacoemulsification and small incision techniques has led to excellent visual results and rapid patient recovery. Posterior capsular rupture does still occur with a reported incidence of 1.9%.¹ However, not all cases of posterior capsular rupture is associated with lens loss. With modern techniques, posterior capsular rupture tends to occur during the irrigation and aspiration phase, after which the majority of lens material has been removed. However, breach of the posterior capsule early in the procedure often leads to luxation of lens material into the vitreous cavity, starting a cascade of complications unless the problem is corrected. Zonular rupture may result in loss of an essentially complete lens posteriorly. Although the exact incident of retained lens material in all cases of posterior capsular rupture is uncertain, older data estimated the rate to be up to 4%.² Possibly because of better techniques, a large case series has a lower reported incidence of 0.20%.³

IMMUNOPATHOLOGY OF RETAINED LENS MATERIAL

The anterior chamber and eye itself are unique in that they are relatively immune privileged. Under normal conditions, there is minimal ocular immune surveillance due, in part, by the blood–eye barrier. After eye injury, however, blood vessels become incompetent and an immunologic response occurs. Early in the response, there is the immediate but transient presence of neutrophils. Next follows a cell-mediated inflammatory response, mainly of T lymphocytes and macrophages. T cells are, however, antigen specific, binding to their specific antigen and releasing cytokines that are cytotoxic to target cells. Macrophages, however, are not antigen specific and attack targeted cells through their phagocytic properties. Additionally, macrophages have an important role in antigen presentation, cytokine secretion, and cytotoxicity.

The immunopathology of lens-induced uveitis remains to be completely elucidated. It is thought that the mechanism maybe a delayed hypersensitivity reaction rather than a rejection of antigenic tissue. Macrophages predominate in the inflammatory reaction from retained lens material. They appear to be activated, then mediate and amplify the immune reaction. Epithelioid and giant cells can be formed as well as phacolytic cells, (macrophages with ingested lens material). Histiologic studies of vitreous specimens in eyes with luxated lens material have shown no macrophage response three days after lens loss. The inflammatory response gradually increases, and by 90 days, 80% of cases demonstrated a macrophage response. The increase in response is linear up until 28 days. After 90 days, there seems to be a decrease in this response.^4,5

MANAGEMENT BY THE ANTERIOR SEGMENT SURGEON

Loss of lens material can occur even in the hands of an experienced cataract surgeon. The surgeon's quest for immediate patient satisfaction and prompt visual improvement can influence surgeons to proceed with aggressive attempts to remove dislocated lens material. Fishing in the vitreous cavity in the attempt to remove lens fragments is often an invitation for disaster. Similarly, aggressive attempts to irrigate lost lens material anteriorly can cause retinal tears and bleeding.

Cortical material is typically easier to manage and smaller in nature than nuclear material when lost. Small cortical particles that are lost posteriorly during the irrigation and aspiration phase can generally be left in place although the patient must be monitored for an inflammatory reaction and development of cystoid mocular edema (CME). Impending loss of larger cortical fragments can sometimes be prevented by injection of viscoelastic material under the fragment to inhibit posterior dislocation. This allows not only lenticular support, but also displaces the vitreous posteriorly to allow safe removal of the lens material with minimal vireo-retinal traction. Additionally, decreasing the irrigation rate maybe helpful in reducing hydration of the vitreous and minimize prolapse of the vitreous into the anterior chamber and posterior migration of lens particles.

Management of dislocated nuclear lens material or, more typically, the lens in toto is much more difficult. Major loss of nuclear material or the entire lens occurs early in the procedure from either loss of a continuous curvilinear capsularrhexis with posterior capsular rupture or zonular dehiscence. Commonly, the anterior segment surgeon has little time to stabilize the larger lens piece as it sinks posteriorly out of view. Unfortunately, nuclear material in the vitreous cavity is associated with an increased risk of inflammation, glaucoma, and corneal decompensation. If the nuclear material is still within the iris or lens capsular plane, stabilization with a combination of a viscoelastic and a secondary instrument inserted underneath the particle can allow enough time to prevent posterior dislocation. Occasionally, the lens can then be lifted and placed in the peripheral anterior chamber angle, allowing time to make a limbal incision to remove the larger lens fragment. Care must be taken to facilitate a complete vitreous removal from the anterior chamber and entry incision wound. Typically, the vitreous cutter can be inserted safely to just below the iris plane to faciliate vitreous clean up and reduce the risk of vitreoretinal traction during intraocular lens insertion. If enough capsular support remains, placement of the intraocular lens in the bag or sulcus is desirable. Otherwise, placement of anterior chamber intraocular lens may be elected. Although, there is evidence that final visual acuity with posterior chamber lenses may be slightly better statistically than with anterior chamber lenses.^6–9

If lens material is lost below the iris/lens plane, aggressive retrieval is not advisable. Attempts to aspirate lens material with the phacoemulsification tip in the vitreous cavity is not recommend and is fraught with complications.¹⁰ If one has immediate access to a vitreoretinal surgeon, pars plana retrieval at the time of the complication may be possible.^3,9 Some authors have advocated a pars plana approach by the cataract surgeon to stabilize dislocated nuclear material with either a secondary instrument or viscoelastic material.¹¹ Unfortunately, many anterior segment surgeons may not have extensive training in pars plana manipulation and its potential complications. Additionally, despite promising reports, case series are still small, and it is difficult to determine if aggressive retrieval of lens material through a pars plana approach by a anterior segment surgeon should be recommended at this time.

A preferred approach would be to place the intraocular lens if possible, remove those particles readily accessible, and then close the eye. In those circumstances where there is a vitreoretinal surgeon readily available and the operating room is suitability equipped, definitive removal of dislocated lens material can be accomplished. However, in most instances it is best to discuss the problem with the patient and refer the patient the next day for further evaluation.

We recommend that at the conclusion of a complicated cataract surgery a subconjunctival injection of a short-acting steroid to minimize the inflammatory response and cystoid macular edema. Frequent postoperative topical steroids, antibiotics, and cycloplegics should be initiated.

POSTOPERATIVE EVALUATION

Early postoperative evaluation can be difficult due to the presence of corneal edema. Additionally, intraocular pressure may be elevated because of lens material, or more typically, remaining viscoelastic material. Incision wound integrity should be carefully inspected, particularly if the intraocular pressure is low. The presence of vitreous strands incarcerated into the cataract wound can act as a source for endophthalmitis or cystoid macular edema. Intraocular lens placement with a poorly supported capsule can lead to phacodonesis and possible intraocular lens dislocation into the vitreous cavity. Cortical material can become very flocculent and mimic a pseudo-hypopyon in the anterior chamber.

Despite these potential problems, early evaluation of the posterior segment is invaluable in assessing retinal complications after surgery and determining the timing of definitive surgery. Frequently, the view is compromised because of corneal edema, miotic pupils, and lens particles. Ultrasonography can readily identify the amount of nuclear and cortical material present in the posterior segment. Cortical material typically produces a snowstorm appearance on ultrasonography, with larger pieces demonstrating irregular borders deposited inferiorly (Fig. 1). Nuclear material typically is found inferiorly and not suspended in the vitreous and is acoustically denser with more regular borders (Fig. 2). Ultrasonography can also identify areas or vitreal-retinal traction, retina tears, or retina detachment not otherwise easily discernable on funduscopic examination.

Fig. 1 Contact B-scan ultrasonogram demonstrates snowstorm appearance of the vitreous from greater amounts of lens material than suspected on clinical examination.

Fig. 2 Contact B-scan untrasound shows nuclear fragment in the inferior periphery of the vitreous cavity in an eye with chronic low-grade inflammation and macular edema.

SEQUELAE OF RETAINED LENS FRAGMENTS

BULLOUS KERATOPATHY

Corneal edema can occur after phacoemulsification even without the presence of retained lens material (Table 1). Loss of endothelial cells from high phacoemulsification power can result in persistent, pseudophakic bullous keratopathy. Additionally, retained lens material and uveitis can result in elevated intraocular pressure contributing to further corneal decompensation. Treatment consists of management of the underlying condition. Topical steroid therapy aids in decreasing the inflammatory response. A multitude of topical pressure lowering agents now exist to control elevated intraocular pressure. Oral carbonic anhydrase inhibitors can be added to topical regimens to lower intraocular pressure in recalcitrant cases. However, in 10% of cataract surgeries complicated by retained lens material, corneal edema will persist often requiring a penetrating keratoplasty.^9,12–15

TABLE 1. Complications From Retained Lens Fragments Following Phacoemulsification

Complication	Percentage
Vitreous opacification*	90%
Uveitis	57%
Glaucoma	52%
Corneal edema	45%
Retinal detachment	7%
Cystoid macular edema†	7%

*Visual acuity of 20/200 (20/60) or less
†Difficult to assess because of opaque media.
(Data from Gilliland et al. Retained intreavitreal lens fragments after cataract surgery. Ophthalmology 99:1263, 1992)

UVEITIS

Inflammatory response to retained lens fragments consists mainly of macrophages engulfing lens material. Inflammation occurs in 25% to 50% of patients with dislocated lens fragments depending on the amount of lens material present.^4,5,13 Onset can be extremely variable with quiescence for weeks, only to develop severe inflammation and cystoid macular edema later. The inflammation, however, differs from the severe granulomatous response seen from reaction to lens proteins released through an intact capsule from a hypermature lens. This reaction is an antigen-antibody–mediated response to previously sequestered lens proteins versus the cell-mediated response seen in retained lens material.

Cystoid macular edema can also be present from the escalating inflammation. Recognition and management of the inflammatory response is vital since the presence of severe inflammation is a poor prognostic sign and frequently augurs a poor final vision.^6,12,16–18

GLAUCOMA

Increased intraocular pressure can be present in 50% of patients with retained lens fragments.^{13,15,19–21} In the immediate postoperative period, increases in intraocular pressure tend to be caused by retained viscoelastic material, hyphema, and lens debris. As the inflammatory response worsens, pressure rise can be secondary to the inflammatory response or rarely, pupillary block from posterior synechiae. Occasionally, topical treatment with steroids can induce an idiosyncratic rise in intraocular pressure. This typically has an onset 10 days after initiation of therapy with a quiet appearing anterior chamber. Fortunately, intraocular pressure can be lowered with currently available medical therapies or by the surgical intervention of removing lens fragment particles. Nonetheless, a manageable rise in intraocular pressure does not seem to have a negative effect on final visual acuity.^12,15,22

RETINAL DETACHMENT

The presence of retinal detachment remains one of the most serious factors effecting final visual acuity.²³ The presence of retinal detachment at the time of initial evaluation occurs in 4% to 10% of patients, although the percentages have declined somewhat in recent years. At the time of surgery to remove retained lens material, retinal tears and detachment may also be discovered. Additionally, there can be significant comorbidities such as giant retinal tears, suprachroidal hemorrhages, and endophthalmitis. Proliferative vitreoretinopathy may occur and usually results in a final vision of 20/200 or less (Fig. 3). In general, retinal reattachment is still achieved in 90% of patients with complicated surgery from retained lens material. However, 31% of patients require more than one surgery. Only 48% of patients achieve final visual acuity of 20/100 or better.^17,21,24,25

Fig. 3 Typical retinal detachment associated with retained lens fragments. Multiple tears are present from vitreal-retinal traction during attempted lens retrieval. Early proliferative vitreoretinopathy is evidenced by the rolled edges of tears.

CYSTOID MACULAR EDEMA

Cystoid macular edema is another important factor affecting final visual acuity. Although macular edema can occur from any lens surgery, prolonged surgery and phacoemulsification power can increase the incidence and severity. The occurrence of uveitis in retained lens material cases also increase the prevalence of CME and offers a poorer visual prognosis.¹⁵

ENDOPHTHALMITIS

The incidence of endophthalmitis in eyes with retained lens material after cataract extraction is rare. However, the exact incidence is unknown. Patients present with signs and symptoms typical of endophthalmitis with ocular pain and inflammation. Hypopyon must be differentiated from the pseudohypopyon secondary to retained lens material. Typically, endophthalmitis produces a more cellular reaction in the anterior chamber as well as a fibrinoid reaction. The decision for surgical intervention versus medical management is unclear. No current studies have evaluated the diference in regard to final visual acuity. Due to the severity of the disease and possible confusion in differentiating the clinical picture, however, we feel that early surgical intervention is prudent in cases of suspected endophthalmitis in the setting of retained lens material. In a small case series, a majority of such patients achieved better than 20/400 acuity following vitrectomy and use of intravitreal antibiotics.²⁶

TIMING OF VITREOUS SURGERY

Postoperative management involves mainly of recognizing factors that significantly affect final visual acuity, specifically, retinal detachment and cystoid macular edema. Medical management of the sequelae of retained lens material involves mainly topical therapy with topical steroids, antibiotics, and cyloplegics. Subconjunctival injection of steroids postoperatively may reduce the immediate, post-operative inflammation. Intraocular pressure-lowering treatment can be initiated at the time of observed pressure increase.

Timing of vitreous surgery is controversial and not clearly defined. Common indications for the initiation of surgical intervention include the presence of retinal detachment, persistent uveitis and glaucoma, and visual loss from lens particle opacities (Table 2).²⁷ Frequently, early intervention is difficult because of corneal edema and pupillary miosis. Although with newer, wide angle, viewing systems this is not an insurmountable problem.

TABLE 2. Indications for Surgery

Indications for Surgery
Poor visual acuity from lens particles or opaque vitreous
Uveitis (persistent)
Glaucoma
Corneal edema secondary to lens particles
Retinal detachment

Prolonged observation and topical medical therapy will typically allow a sufficient view into the vitreous cavity to safely perform surgery but at the risk of persistent CME and glaucoma. It is not uncommon to see late exacerbations of macular edema for up to 12 months in patients in whom observation was chosen. Of these patients, 50% will demonstrate recurrences of uveitis and glaucoma. Close observation is therefore of utmost importance to ensure that all of the fragments are safely absorbed and complications minimized.¹³

In those patients for whom surgery is indicated, there currently are no definitive studies demonstrating a benefit for earlier surgical intervention. The incidence of postoperative glaucoma appears no higher if surgery is performed later, though this data is conflicting. However, a recent comparative study suggests that vitrectomy within 3 weeks postoperatively, is associated with better visual results and lower incidence of glaucoma and retinal detachment then in eyes with further delay of surgery. Our own observations of patients with small amounts of cortical lens material treated medically showed that over 50 % developed CME. Earlier intervention may therefore be warranted.^{4,5,8,12,16,28}

VITRECTOMY TECHNIQUE

A standard three-part pars plana vitrectomy approach in conjunction with vitreous cavity phacofragmentation is sufficient to remove the majority of lens material in all but the most unusual cases. If lens particles are small or consist mainly of cortical material, the use of the new 25-gauge sutureless system may permit faster closer and healing time.²⁹

Prior to vitreous surgery, careful assessment of the anterior segment is mandatory. Specifically, the cataract wound incision should be inspected to ensure that no vitreous is incarcerated and that the wound is adequately closed. Securing the cataract incision with sutures maybe necessary. Vitreous should be meticulously removed from the anterior chamber. Frequently, vitreous that has prolapsed into the anterior chamber will be pulled back with removal of the anterior vitreous located behind the lens and iris plane. Occasionally, vitreous is still seen in the anterior chamber and insertion of the vitrectomy cutter into the anterior chamber is needed. If the intraocular lens is relatively stable or if the lens is an anterior chamber lens, the cutter can be inserted between the lens and iris into the anterior chamber (Fig. 4). Care must be taken because aspiration in the anterior segment can collapse the chamber due to infusion pressure being directed into the vitreous cavity. Finally, in cases when vitreous is difficult to identify, we have found that injection of triamcinolone into the anterior chamber makes visualization of the vitreous extremely straightforward due to steroid adherence to vitreous strands.

Fig. 4 Posterior capsule and cortical material removed (top). Vitreous cutter inserted into the anterior chamber and cortical material aspirated (bottom).

Removal of cortical material from the vitreous is easy. Most pieces are readily aspirated into the vitreous cutter. Larger, denser fragments can be removed by gently “stuffing” the material into the cutter opening with the light pipe. It is imperative to remember that most of the vitreous should be removed before manipulation of larger lens fragments to limit any vitreal-retinal traction and subsequent retinal tears.

Larger nuclear pieces, if sufficiently soft, can also be removed with the vitreous cutter. More commonly, the phacofragmenter is needed to remove nuclear material. The technique typically involves gentle aspiration with the phacofragmenter tip to lift the piece into the midvitreous cavity (Fig. 5). A light pipe, especially one with a spatulated extension, can be used to stabilize the fragment. Ultrasound is then initiated to remove the piece. Not uncommonly, the lens piece will disengage from the fragmentation tip. We have found that lower energy or energy set in the pulse mode is beneficial in these circumstances. Higher aspiration rates are also helpful in prevent lens fragment from becoming disengaged from the fragmentation tip and falling onto the retina.

Fig. 5 Lens material is gently engage with aspiration (1) and lifted to the midvitreous (2) and phacoemulsification initiated.

If a phacofragmenter is not available, a phacoemulsification tip with the sleeve in place can be used to remove lens material. However, the incision must be increased to 3 mm and the infusion rate increased.

Retinal contusions can occasionally occur from lens material falling back onto the retina. The use of liquid perfluorocarbons can act as a buffer to minimize injury (Fig. 6). In our experience, however, smaller particles can get trapped beneath the perfluorocarbon liquid and hinder removal. With the newer instrumentation and techniques, retinal contusion from dropped particles occurs infrequently and the use of perfluorocarbon is rarely necessary. We have found the use of perfluorocarbon more beneficial in cases of dislocated lenses combined with total retinal detachments. Partial perfluorocarbon placement can temporarily flatten the retina to allow a more complete vitreous removal and minimizing the chance of retina incarceration into the fragmentation tip.

Fig. 6 Liquid perfluorocarbon used to float lens fragments off retinal surface and buffer retina from dropped lens particles.

Large pieces of nuclear material almost never need to be removed from the eye through a limbal incision. Sizable chunks can be managed by using a divide-and-conquer technique and subsequently removed with the phacofragmenter.

Rarely, perfluorocarbons are needed to float the intact lens or large fragment up to the iris plane to facilitate removal. Additionally, lens removal through an enlarged pars plana incision is rarely necessary. With modern instrumentations, these techniques have limited future use (Table 3).

TABLE 3. Intraoperative Management Scheme

Condition	Management
Cataract wound	1. Rehydrate clear cornea incision
dehiscence	2. Place additional 10–0 sutures
Choroidal detachment	1. Prevent intraoperative hypotony
(hemorrhagic/	2. Expedite completion of surgery
exudative)	3. Use post-operative steroids
Corneal edema	1. Apply topical hyperosmotic agent
	2. Perform corneal epithelium debridement
	3. Place a temporary keratoprosthesis
	4. Perform penetrating keratoplasty
Retinal detachment	1. Primary vitrectomy with 360° laser and gas tamponade
	2. Place scleral buckle
	3. Meticulous inspection of retinal periphery for additional breaks
Cystoid macular edema	1. Elimination of any source of secondary inflammation (e.g., vitreous incarceration, papillary capture, etc.)
	2. Placement of intraocular steroids

RESULTS OF VITRECTOMY

Vitrectomy has proved to be effective in rapid restoration of vision in eyes with retained lens fragments. At least half of patients obtain 20/40 or better vision.^12,15,24 Intraocular lens placement at the time of initial surgery does seem to affect postoperative vision. Specifically patients with posterior chamber intraocular leness tend to have better final visual acuity after surgery for retained lens material.

Patients with ultimate poor vision often have a history of retinal detachment or cystoid macular edema. Unfortunately, retinal detachment can be seen in 12.8% of cases, with 7.3% occurring before or during pars plana vitrectomy and 5.5% occuring after vitreous surgery. Almost half of patients obtain better than 20/100 vision with reattachment rates approaching 90.9%.¹⁷

Cystoid macular edema can compromise visual acuity following vitrectomy. In patients with complicated anterior segment surgery, placement of intravitreal triamcinolone at the time of surgery may rapidly resolve cystoid macular edema and improve visual acuity. We have found that such placement of triamcinolone at the time of surgery has few side effects.

CONCLUSION

Fortunately, retained lens material following cataract extraction is becoming less frequent. Careful postcataract surgery assessment of the anterior and posterior segment permits a logical decision regarding observation versus vitreous intervention. Vitrectomy can be deferred if only small cortical materials are present. Precise timing of vitrectomy remains controversial.

REFERENCES

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7. Collins JF, Gaster RN, Krol WF, et al: A comparison of anterior chamber and posterior chamber intraocular lenses after vitreous presentation during cataract surgery: the Department of Veterans Affairs Cooperative Cataract Study. Am J Ophthalmol 136:1, 2003

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