Intracapsular Lens Deliveryduring AttemptedExtracapsular CataractExtraction

Association with Capsulorrhexis

DAVID J. HARRIS, Jr., MD/,2 CHARLES S. SPECHT, MD3

Abstract: Continuous circular tear capsulotomy, or capsulorrhexis, has becomea popular technique in cataract extraction, especially in phacoemulsification.The authors report on six cases from five different surgeons at three institutions,in which the entire lens was inadvertently delivered on attempted expressionof the nucleus after circular capsulorrhexis. In one case, scanning electronmicroscopy suggests that the smooth edge of a small, closed, capsular tear isnot capable of controlled extension to allow nuclear egress. Therefore, superiorradial anterior capsular relaxing incision is recommended when circular cap­sulorrhexis is used in extracapsular cataract extraction.Ophthalmology 1991; 98:623-627

Continuous tear capsulotomy, also known as capsu­lorrhexis, has revolutionized cataract surgery. By assuringplacement of the lens prosthesis within the capsular bag,this technique allows the surgeon to implant an intraocularlens (IOL) designed specifically for capsular support, withno contact between the lens and vascular structures of

Originally received: September 26, 1990.Revision accepted: December 27, 1990.

1 Department of Ophthalmology, National Naval Medical Center, Bethesda.2 Ophthalmology Section, Department of Surgery, University of Tennessee

Medical Center, Knoxville.3 Department of Ophthalmic Pathology, Armed Forces Institute of Pathol­

ogy, Washington, DC.

Presented at the American Academy of Ophthalmology Annual Meeting,Atlanta, OctjNov 1990.

The opinions or assertions contained herein are the private views of theauthors and are not to be construed as official or as reflecting the viewsof the Departments of the Army or Navy, or the Department of Defense.

Reprint requests to David J. Harris,Jr., MD, University of Tennessee MedicalCenter, Suite 324.1928 Alcoa Highway, Knoxville, TN 37920.

the eye. Other advantages of this technique, such as easeof cortical removal and absence of radial tears, have beenreviewed by Gimbel and Neuhann.' Relatively few com­plications with capsulorrhexis have been reported.

Capsulorrhexis has been advocated for extracapsularcataract extraction as well as phacoemulsification. Afterone of us (DJH) observed a case of inadvertent intracap­sular lens delivery after capsulorrhexis at Bethesda NavalHospital, informal questioning of the staffsof that hospitaland two other hospitals revealed five similar cases. Therecords of these cases, which occurred between 1987 and1989, were reviewed. We report these cases, including thehistopathologic findings in three of them. Based on ourfindings, we suggest that one or more peripheral, superi­orly oriented, radial capsulotomies be placed after cap­sulorrhexis to ensure orderly egress of the nucleus.

CASE REPORTS

Case 1. A 74-year-old woman was scheduled for extracapsularcataract extraction with intraocular lens (ECCE IOL) in the left

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Fig 2. Lens specimen from case 2. Capsulotomy edges (arrows) andnuclear equator (*) in configuration similar to Case I, showing nuclearrotation (periodic acid-Schiff stain; original magnification, X20).

Fig 1. Lens specimen from case I. The edgesof the capsulorrhexis (arrows)demonstrate that the (presumably superior) nuclear equator (*) has ro­tated 90° within the softer cortical material. The thin posterior capsuledoes not show wellat this magnification but is intact (periodic acid-Schiffstain; original magnification, X20).

Case 3. A 78-year-old woman was scheduled for ECCE IOLin the right eye. She had mild corneal guttae and age-relatedmacular degeneration. A 5-mm horizontal X 6-mm vertical ovalcapsulorrhexis was performed using a bent needle tip. The nu­cleus was loosened from the cortex but not prolapsed. After astandard limbal incision, superior scleral pressure resulted inintracapsular delivery of the lens. The vitreous face remainedintact. An anterior chamber IOL was placed. Except for a tran­sient rise in intraocular pressure, the postoperative course wasuneventful. The lens was processed for scanning electron mi­croscopy.

Case 4. A 65-year-old man was scheduled for ECCE IOL inthe right eye. The ocular history was negative except for cataracts.An approximately 6-mm capsulorrhexis was performed with abent needle tip. The nucleus was loosened but not prolapsed.After a limbal incision, scleral pressure caused delivery of theentire lens without vitreous loss. An anterior chamber IOL wasplaced and the postoperative course was uneventful.

Case 5. A 70-year-old woman was scheduled for ECCE IOLin the right eye. The ocular history was unremarkable exceptfor cataracts. Capsulorrhexis was performed with a bent needletip. Superior limbal pressure caused delivery of the entire lens,but this was not recognized intraoperatively. A posterior chamberlens was placed behind the iris and remained stable. On the firstpostoperative day, total absence of the lens capsule was noted,but the IOL remained centered and the vitreous face remainedintact.

Case 6. A 75-year-old man was scheduled for ECCE IOL. Hiscourse was similar to that of case 4, with delivery of the entirelens but no violation of the vitreous face. After IOL placement,the postoperative course was uneventful.

HISTOPATHOLOGY

The lens specimen in cases 1 and 2 were immersed in10% neutral buffered formalin and prepared in the usualmanner for light microscopy. Sections through the longestaxes were stained with the periodic acid-Schiff reagent toemphasize the lens capsule (Figs I, 2). In both cases, thenucleus had rotated 90° within the capsule, so that itsequator projected from the anterior capsule defect.

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eye. The operative eye was considered a glaucoma suspect andwas under therapy with dipivefrin with intraocular pressure be­low 20 mmHg. There was no history of trauma or exfoliation.A capsulorrhexis, 6 mm in diameter, wasperformed with forceps,followed by nuclear hydrodissection and dislocation of the su­perior equator of the nucleus into the anterior chamber. An 11­mm chord length limbal incision was made. Superior limbalpressure resulted in delivery of the entire lens. Vitreous presentedat the wound and was removed with an automated vitrector.An anterior chamber IOL was placed. The postoperative coursewas uneventful. The lens was processed for light microscopy.

Case 2. An 84-year-old woman with no ocular abnormalityother than cataract was scheduled for ECCE IOL in the left eye.A 6-mm diameter forceps capsulorrhexis, hydrodissection, andan Ll-mm limbal incision were performed. Limbal pressure re­sulted in expression of the entire lens as well as vitreous loss.Mechanical anterior vitrectomy and anterior chamber IOL in­sertion were performed. The postoperative course was unevent­ful. The lens was processed for light microscopy.

SCANNING ELECTRON MICROSCOPY

The specimen in case 3 was prepared in standard fash­ion for scanning electron microscopy. The specimen wasscanned on its anterior surface. At low power (Fig 3), arelatively small circular anterior capsular defect is seen,with loose lens epithelial tissue protruding. The nuclearequator does not appear to have prolapsed as in cases 1and 2. At a higher magnification (Figs 4,5), details of thetorn capsular edge are clearly seen. The extremely sharpand smooth edge, even at high power, shows no smallradial splits or tears. Fibrillar material is seen on the cap­sular surface at high power and in the equatorial regionin association with zonular remnants (Fig 6). This rep­resents nonspecific proteinaceous debris, as it does nothave the typical appearance ofpseudoexfoliative materialon scanning electron microscopy.

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HARRIS AND SPECHT • ZONULYSIS AFTER CAPSULORRHEXIS

Fig 3. Lens specimen from case 3. Lens cortex (*) protrudes from roundcapsulorrhexis (arrows) (scanning electron microscopy; original magni­fication, X12).

Fig 4. Lens specimen from case 3. Anterior capsule shows extremelysmooth tear (arrows). Fibrillar material (*) on anterior capsule representsnonspecific proteinaceous debris, not pseudoexfoliation (scanning elec­tron microscopy; original magnification, X300)

DISCUSSION

In phacoemulsification, the capsulectomy needs onlyto be large enough to admit the ultrasonic instrument andthen an IOL. Because a circular capsulorrhexis can bedeformed to an oval during IOL placement, a 5-mm di­ameter opening can admit a 7-mm diameter IOL. How­ever, if the nucleus is to be expressed in one piece, thecapsular opening must be large enough to allow nuclear

Fig S. Lens specimen from case 3. Detail of capsulorrhexis shows a nearperfect capsule tear edge (arrows) (scanning electron microscopy; originalmagnification, X1000).

Fig 6. Lens specimen from case 3. Zonular fibers (arrow) and fibrillardebris (*) are seen (scanning electron microscopy; original magnification,X220).

egress. In the cases presented, the force necessary to propelthe nucleus through the anterior capsular opening wasapparently greater than that required to rupture thezonule.

CAUSES OF ZONULAR DEHISCENCE

Zonular dehiscence can complicate cataract surgery re­gardless of capsulotomy technique.? In addition to the

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Fig 7. Use of a bent needle tip to create a small radial tear in the superiorportion of an otherwise smooth circular capsulorrhexis (arrow).

obvious association with previous trauma to the zonuleand conditions causing congenital zonular weakness suchas Marfan's syndrome, zonular dialysis has been stronglyassociated with pseudoexfoliation syndrome.v' However,in a recent study, only I in 5 cases of pseudoexfoliationsyndrome with zonular dialysis during cataract surgeryresulted in total lens delivery. Although the fibrillar ma­terial seen in case 3 could conceivably represent atypicalpseudoexfoliation, it is unlikely that pseudoexfoliationsyndrome and other causes of zonular weakness weremissed preoperatively in all the cases we have reported.

REVIEW OF THE LITERATURE

Others have noted similar problems when using cap­sulorrhexis in extracapsular surgery. Maher5 noted cum­bersome nuclear expression with occasional anterior pro­lapse of the inferior equator ofthe lens. Almallah" reportedtwo cases of inadvertent intracapsular lens delivery, aswell as one case of partial zonular dehiscence after cap­sulorrhexis. Hunyor" observed intracapsular lens deliveryin another three cases. In addition, through personalcommunication, we are aware of several other similarmishaps. We surmise that this complication is relativelycommon. The only other complication that has been spe­cifically ascribed to capsulorrhexis is capsular bag disten­tion."

MECHANICS OF NUCLEAR EXPRESSION

If one assumes that the edge of a continuous tear cap­sulotomy will stretch or split radially only under extremeforce, then there are only two ways for a relatively largenucleus to escape from the capsular opening. First, it ispossible that the edge of the capsulotomy could shear offsofter peripheral nuclear material, allowing the harder coreto pass through. Second, since the anteroposterior radius

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of an ellipsoidal nucleus is shorter than the other two,presumably equal, radii, tilting of the nucleus so that itselliptical profile passes through the opening will alloweasier egress. Shimuzu? and Hunyor" have advocatedmethods of prolapsing the superior nuclear equator toachieve this goal. However, the histologic appearance ofthe expressed lenses in cases 1 and 2 demonstrate thatthis technique may not be adequate even with a roundcapsulorrhexis 6 mm in diameter. In theory, superior nu­clear equator prolapse can assure safe expression only ifmore than one half of the nucleus is delivered anterior tothe capsular opening. Quantification of the strength andelasticity of the aging human anterior lens capsule is out­side the scope of this study but is worthy of further re­search. Unfortunately, mathematical determination of thediameter of circular capsulorrhexis needed to allow nu­clear egress is more difficult. Not only is the nucleus ahistologically ill-defined structure, but the "clinical" nu­cleus enlarges with age. Nuclear size seems to vary a greatdeal even within age groups, dependent on the type oflens opacity present.

PREVENTION OF ZONULYSIS

Many methods have been proposed to allow orderlynuclear egress through a continuous capsulotomy.Witreman'" advocated aD-shaped capsulotomy followedby hydrodissection to deliver the nucleus atraumatically.Hunyor" favors hydrodissection also. Shimuzu? recom­mended a two-handed technique to prolapse the entirenucleus into the anterior chamber before expressionthrough the wound. All of these methods require that thenucleus be physically capable of passing through the cap­sular opening. Clearly, a larger opening will allow easiernuclear delivery. However, the nuclear size is never knownexactly, and a large diameter capsulectomy carries a riskof disinsertion of anteriorly anchored zonular fibers.

Another approach is to inject a viscoelastic substancebeneath the nucleus so that high pressure within the cap­sular bag, as opposed to high vitreous pressure, expels thenucleus. Presumably, the thin posterior lens capsule,rather than the zonule, would then be the susceptiblestructure if too much pressure is generated.

For these reasons, we favor a radial tear in the anteriorcapsule, which can enlarge to accommodate the nucleus.Maher" recommended cuts at the 3- and 9-0'clock posi­tions. We prefer the method ofAlmallah,6 who advocateda single cut superiorly. This technique (Fig 7), performedwith a bent needle tip, encourages the superior equatorof the nucleus to prolapse first and provides easier aspi­ration of superior cortex while leaving only two comersor flaps in the anterior capsule. It is important that thehaptics of the IOL be placed horizontally. If one hapticis directed toward the superior radial tear, late asymmet­rical capsular contracture can push the haptic through thetear, resulting in marked lens decentration.

In approximately 100cases involving both resident andstaff cataract surgery, we have not observed this tear to

HARRIS AND SPECHT • ZONULYSIS AFTER CAPSULORRHEXIS

Fig 8. Slit-lamp photography with broad tangential illumination showsminimal upward decentration of an intraocular lens placed within thecapsular bag after circular capsulorrhexis and an intentional superiorradial tear. Extreme upper edge of intraocular lens is behind the dilatedpupillary margin, while inferior optic edge (arrow) is exposed.

Fig 9. Slit-lamp photography of near-perfect postoperative centration ofan intraocular lens behind a circular capsulorrhexis following phaco­emulsification.

extend posteriorly or to result in vitreous loss or zonulardehiscence. We have occasionally observed subtle late su­perior IOL decentration (Fig 8) compared with the near­perfect centration seen with capsulorrhexis alone andphacoemulsification (Fig 9). However, we are not awareof any case where this amount of decentration, presum­ably caused by asymmetric capsular contracture, hascaused any visual symptom.

However, we recommend the use of a large diameter(7-mm) optic to minimize the effect of any decentration,since the wound readily admits such a lens.

PHACOEMULSIFICATION VERSUSEXTRACAPSULAR EXTRACTION

One obvious way to avoid alterations in the capsulor­rhexis technique is to perform phacoemulsification exclu­sively. Although a discussion of the relative merits of thetwo procedures is beyond the scope of this report, we favorplacement of a superior capsular cut in situations whereconversion to extracapsular cataract extraction may berequired, such as early resident surgery, transition fromextracapsular extraction to phacoemulsification, and casesof extremely large or brunescent nuclei. This capsular tearcan be placed after partial nuclear emulsification, but vi­sualization may not be ideal.

CONCLUSION

Capsulorrhexis appears to be associated with increasedrisk of total zonular disruption during attempted ECCE.A single, superior, radial capsular cut reduces this riskwhile preserving most of the advantages of the capsulor­rhexis technique. Thus, capsulorrhexis can be safely usedin both phacoemulsification and ECCE.

REFERENCES

1. Gimbel HV, Neuhann T. Development, advantages, and methods ofthe continuous circular capsulorrhexis technique. J Cataract RefractSurg 1990; 16:31-7.

2. Goodman DF, Stark WJ, Gottsch JD. Complications of cataract ex­traction with intraocular lens implantation. Ophthalmic Surg 1989; 20:132-40.

3. Goder GJ. Our experiences in planned extracapsular cataract extrac­tion in the exfoliation syndrome. Acta Ophthalmol Suppl 1988; 184:126-8.

4. Skuta GL, Parrish RK II, Hodapp E, et al. Zonular dialysis during ex­tracapsular cataract extraction in pseudoexfoliation syndrome. ArchOphthalmol1987; 105:632-4.

5. Maher JF. Nucleus expression after capsulorrhexis. [Letter] J CataractRefract Surg 1988; 14:693.

6. Almallah OF. Capsulorrhexis complications with planned extracapsularcataract extraction. [Letter]. J Cataract Refract Surg 1989; 15:232-3

7. Hunyor ABL. Avoiding capsulorrhexis complications with extracapsularcataract surgery [Letter]. J Cataract Refract Surg 1989; 15:464.

8. Davison JA. Capsular bag distension after endophacoemulsificationand posterior chamber intraocular lens implantation. J Cataract RefractSurg 1990; 16:99-108.

9. Shimuzu K. Double-hook extraction technique. J Cataract Refract Surg1989; 15:702-4.

10. Witteman GJ. Avoiding capsulorrhexis complications with extracapsularcataract surgery [Letter]. J Cataract Refract Surg 1989; 15:463-4.

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