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Year : 1999  |  Volume : 47  |  Issue : 3  |  Page : 173-176

Incidence and management of posteriorly dislocated nuclear fragments following phacoemulsification.

Schell Eye Hospital, Christian Medical College, Vellore, India

Correspondence Address:
A Mathai
Schell Eye Hospital, Christian Medical College, Vellore
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Source of Support: None, Conflict of Interest: None

PMID: 10858772

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PURPOSE: To report the incidence, management and complications of nucleus dislocation into the vitreous during phacoemulsification. METHODS: Retrospective review of 1250 consecutive phacoemulsification performed by consultants and residents in a teaching hospital. RESULTS: The incidence of nucleus drops was 0.8% (10 out of 1250). Loss of nuclear fragments occurred during phacoemulsification in 9 patients. In one, the dislocation was caused by hydro-dissection. All except one patient (who refused further intervention) underwent pars plana vitrectomy with removal of nuclear fragments. Eight of them had intraocular lens (IOL) inserted at the time of cataract surgery or at vitrectomy; one patient was scheduled for a secondary IOL. Postoperative best corrected visual acuity ranged from 6/24-6/6; 8 patients achieved a vision of 6/12 or better. Complications included cystoid macular oedema (5 patients), retinal break (1 patient) and retinal detachment (1 patient). CONCLUSION: Appropriate management of posteriorly dislocated nucleus can restore good visual acuity. The use of phacoemulsification mandates availability of referral facilities for management of complications.

Keywords: Phacoemulsification, posteriorly dislocated nucleus, vitrectomy, complications

How to cite this article:
Mathai A, Thomas R. Incidence and management of posteriorly dislocated nuclear fragments following phacoemulsification. Indian J Ophthalmol 1999;47:173-6

How to cite this URL:
Mathai A, Thomas R. Incidence and management of posteriorly dislocated nuclear fragments following phacoemulsification. Indian J Ophthalmol [serial online] 1999 [cited 2023 Feb 8];47:173-6. Available from: https://www.ijo.in/text.asp?1999/47/3/173/14921


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Phacoemulsification, the preferred method of cataract surgery in the west, is becoming increasingly popular in India. While phacoemulsification has several major advantages, nucleus and nuclear fragment dislocation is a potentially serious complication of this technique.[1][2][3][4][5][6][7][8] This complication may occur during hydrodissection, phacoemulsification of the nucleus in the presence of a posterior capsular tear, posterior extension of a tear in the continuous curvilinear capsulorrhexis (CCC) or a zonular diaysis. While the reported incidence of this complication is 0-18%[9] (the latter figure reported by a surgeon learning phacoemulsification) the more recent literature reports incidences of 0.3%-2.7%.[10],[11] Retained nuclear fragments can result in severe intraocular inflammation, glaucoma, and may lead to loss of useful vision.

The modern management of a nucleus drop requires pars plana vitrectomy by an experienced vitreoretinal surgeon. While successful removal of nuclear fragments can result in good visual recovery,[1][2][3],[5][6][7][8] the requisite instrumentation and trained personnel must be available. With an increasing number of surgeons all over the country learning and performing phacoemulsification, estimating the need for such facilities requires documentation of the incidence of this complication in the Indian context.

  Materials and Methods Top

The posterior nuclear or nuclear fragment drop reported here occurred in a consecutive series of 1250 phacoemulsifications performed during a period of 2 years. The relevant information was retrieved from patient records. The surgeries were performed by one experienced consultant and several other consultants and residents converting to phacoemulsification. The selection of cataracts for those learning phacoemulsification in our centre has been described elsewhere.[12] Beginners operated on nuclear sclerosis grades III or less.[13] The more experienced consultant operated on grade IV and the occasional grade V sclerosis. Totally white and black cataracts were excluded. Phacoemulsification was performed using a standard technique that has been described earlier.[14],[15] Towards the middle of the series, we started using an anterior chamber maintainer in all cases.[12]

When confronted with a nucleus drop, the protocol in our hospital required the operating surgeon to perform a partial anterior vitrectomy with an ocutome vitrector introduced through the side port and a separate infusion source, usually the anterior chamber maintainer. Unless the clinical impression was that of a hard nucleus, the surgeon would implant an IOL. If adequate capsular support was available, a posterior chamber intraocular lens (PCIOL) was preferred. If not, an anterior chamber intraocular lens (ACIOL) or scleral fixated lens was used. In case of doubt, a vitreoretinal surgeon was consulted, and if available, depending on media clarity and state of anaesthesia, the nuclear fragment was removed at the same sitting. Otherwise patients were managed with an elective 3-port pars plana vitrectomy later. Wire-loop vectis or similar devices were not used to retrieve the sunken nucleus or nuclear fragments.

The pars plana vitrectomy and technique of nuclear removal conformed to the published literature.[10],[16],[17] In brief, following pars plana vitrectomy, nuclear fragments were floated up with perfluorocarbon liquid (PFCL) and removed using the techniques of elevation and emulsification with the ultrasonic fragmenter. Softer nuclear fragments were removed with the vitrectomy cutter itself. If the entire nucleus was in the vitreous, the nucleus was floated up into the anterior chamber using PFCL and removed through an extension of the original scleral tunnel incision. If an IOL had not been implanted during the primary surgery, it was implanted at this time. A detailed indirect ophthalmoscopy with scleral depression was performed at the end of the procedure.

Two patients were operated at the same session as the cataract surgery, 6 patients within 2 weeks and one patient within 3 weeks. One patient refused the second surgery and marked intraocular inflammation resulted in a phthisical eye. Eight of the 9 patients had an IOL implanted. In 6, the IOL was implanted at the time of the cataract surgery while in 2 it was implanted during the vitrectomy. Of the 9 patients, 5 had PCIOL placed on the anterior capsule, 2 had sclerally fixated PCIOL, one had an ACIOL and one was slated for a secondary IOL. Further surgeries included endolaser photocoagulation for a retinal break and retinal attachment surgery using 360 encirclage and long-acting gas (C3F8) injection.

  Results Top

The overall incidence of nucleus drop into the vitreous was 0.8% (10 out of 1250 patients). The incidence for the experienced surgeon was 0.3% (2 in 600) and for those learning it was 1.23% (8 in 650). The nucleus drop occurred during the actual process of phacoemulsification in all except one patient. The number of nuclear fragments lost ranged from one to three. In one patient hydrodissection led to a blowout of the posterior capsule with subsequent dislocation of the entire nucleus into the vitreous.

With a postoperative follow up of 18-30 months the best corrected visual acuity ranged from 6/24-6/6; eight patients improved to 6/12 or better. The complications related to management with pars plana vitrectomy are shown in the Table. These included transient intraocular pressure elevation in 5, cystoid macular oedema (CME) in 5, and a commotio retinae-like picture in one patient. The patient who had endolaser photocoagulation for retinal break regained 6/9 and the other patient following retinal attachment surgery regained 6/24 vision.

  Discussion Top

Indian reports on incidence and management of nucleus drop are lacking. Available reports have been limited to mention of the nucleus drop rate in publications dealing with the learning curve.[12],[15] With an increasing number of Indian surgeons converting to phacoemulsification, such data is of critical importance in planning appropriate or relevant treatment facilities.

The combined lens drop rate was 0.8% with both experienced and learning surgeons performing phacoemulsification. This is comparable to published reports.[10],[11] The lowest reported incidence of 0.3% as an "impression" by experienced surgeons is similar to that of the senior surgeon in this study.[10] This rate does overlap the lower limit to 95% confidence interval of the overall incidence (0.3 - 1.3%) and is close to the lower limit of the beginners (0.38 - 2.07%). Since the incidence of nucleus drops was more for those learning the technique, it could be argued that reports that include beginners could overestimate the incidence. In our opinion the spectrum of experienced and learning surgeons more closely resembles the current situation in India. In fact as conversion to phacoemulsification in our hospital is supervised,[12],[25] as far as an estimation for the country is concerned, our rates may actually be an underestimate.

Left unmanaged posterior dislocation of the lens can lead to significant intraocular inflammation, elevated intraocular pressure, corneal oedema, cystoid macular oedema (CME), vitreous haemorrhage, vitreous opacification, retinal tears and detachment.[1][2][3][4][5],[18] Retained lens fragments can be a potentially disastrous complication. It has been suggested that less than 25% retained nucleus may be observed indefinitely and may not need surgical intervention.[5],[10],[19] In one series 9 cases were managed conservatively without surgical intervention.[3] Of these, 50% of eyes developed clinically significant complications such as persistent CME, uveitis, glaucoma and retinal detachment. These findings suggest that eyes even with a minimal amount of posterior dislocated lens material need close observation and half of them eventually need a vitrectomy. Considering the ground realities in our country, we chose to electively remove all nucleus droppings. Also in our opinion it is not easy to clinically assess the size of the nuclear fragment.

Surgical techniques described for the cataract surgeon for retrieval of nuclear fragments includes floating the nucleus anteriorly using a viscoelastic material,[20] vitrectomy using a glass side and co-axial illumination of the microscope,[21] Tennant's method (Jerald L Tennant, M.D., Fun with phako, the basics of phacoemulsification, handout from Dallas Eye Institute. p 18-20), one-port pars plana vitrectomy[22] and 2-port pars plana vitrectomy.[23] Some of these methods can produce potential complications like retinal detachment because of direct traction on the vitreous base and therefore any retrieval of the nucleus from the vitreous should be attempted only with an adequate vitrectomy. The safer technique is a 3-port pars plana vitrectomy[2] with or without use of perfluorocarbon liquid.[17],[24],[25] The PFCL is not an absolute neccessity for retrieval of retained lens fragments but is well suited to cases with co-existing retinal breaks and detachments.

In our series the best corrected visual acuity was 6/24 to 6/6; only one patient had a significant complication requiring reintervention. This is similar to other published reports.[2],[5],[6] Our protocol for the cataract surgeon encountering such a complication followed published guidelines.[12] The incidence of retinal detachment associated with retained lens fragments is 9.6% before vitrectomy and 8.8% following vitrectomy.[26] This high incidence can be reduced if cataract surgeons do not attempt retrieval of the nucleus from the vitreous and instead, a complete vitrectomy before phacofragmentation is performed by the vitreoretinal surgeon.

The optimal timing of vitrectomy has been a matter of debate. To avoid the cycle of progressive lens-induced inflammation, the best time for vitrectomy is at the same sitting as the cataract surgery.[19] This may not be practical due to non-availability of a vitreoretinal surgeon or the anaesthesia wearing off. A delay in vitrectomy of more than 3 weeks could cause an increased incidence of chronic glaucoma,[9] though another study failed to demonstrate statistical difference between time of surgery and final visual outcome or incidence of glaucoma.[3] Most of our cases underwent vitectomy within 2 weeks of initial cataract surgery It has been suggested that a delay of up to 3 weeks is acceptable.[5] This delay may be necessary to reduce corneal oedema and intraocular inflammation. In one of our patients visualization was difficult due to corneal oedema and necessitated waiting for 3 weeks before intervention. Associated retinal tears, retinal detachment and endophthalmitis, however, are all indications for urgent surgical intervention.

In conclusion, retained nuclear fragments after cataract surgery represents a potentially vision-threatening complication. Our small series demonstrates that appropriate management and timely removal of these nuclear fragments by vitrectomy facilitates visual recovery with resolution of complications. However, the required intervention is expensive and labour intensive. We perform a large number of cataract operations in our country; many surgeons voice the opinion that our cataract blind would be best served by advantages offered by phacoemulsification. The relative frequency of nucleus drop with phacoemulsification as well as ethical considerations requires that the patient be informed about this potential complication. Furthermore referral facilities for its management must be available before this technique is used.

  References Top

Blodi BA, Flynn HW, Jr., Blodi F, Folk JC, Daily MJ. Retained nuclei after cataract surgery. Ophthalmology 1992;99:41-44.  Back to cited text no. 1
Lambrou FH, Jr., Stewart MW. Management of dislocated lens fragments during phacoemulsification. Ophthalmology 1992;99:1260-62.  Back to cited text no. 2
Gilliland GD, Hutton WL, Fuller DG. Retained intravitreal lens fragments after cataract surgery. Ophthalmology 1992;9:1263-67.  Back to cited text no. 3
Irwine WD, Flynn HW, JR., Murray TG, Rubsamen PE. Retained lens fragments after phacoemulsification manifesting as marked intraocular inflammation with hypopyon. Am J Ophthalmol 1992;114:610-14.  Back to cited text no. 4
Kim JE, Flynn HW, Jr., Smiddy WE, Murray TG, Rubasmen PE, Davis JL et al. Retained lens fragments after phacoemulsification. Ophthalmology 1994;101:1827-32.  Back to cited text no. 5
Borne MJ, Tasman W, Regillo C, Malecha M, Sarin L. Outcome of vitrectomy for retained lens fragments. Ophthalmology 1996;103:971-76.  Back to cited text no. 6
Kapusta MA, Chen JC, Lam WC. Outcomes of dropped nucleus during phacoemulsification. Ophthalmology 1996;103:1184-88.  Back to cited text no. 7
Wong D, Briggs MC, Hickey-Dwyer MU, McGalliard JN. Removal of lens fragments from the vitreous cavity. Eye 1997;11:37-42.  Back to cited text no. 8
Emery JM, McIntyre DJ. Extracapsular Cataract Surgery. St. Louis, USA:CV Mosby, 1983. pp 340-58.  Back to cited text no. 9
Smiddy WE, Flynn HW Jr. Managing retained lens fragments and dislocated posterior chamber IOLs after cataract surgery. Focal Points. Clinical Module for Ophthalmologists. American Academy of Ophthalmology 1996;Vol XIV No.7:l-14.  Back to cited text no. 10
Pande M, Dabbs TR. Incidence of lens matter dislocating during phacoemulsification. J Cat Ref Surg 1996;22:737-42.  Back to cited text no. 11
Thomas R, Naveen S, Jacob A, Braganza A. The visual outcome and complications of residents learning phacoemulsification. Indian J Ophthalmol 1997;45:215-19.  Back to cited text no. 12
Emery JM, Mc Intyre DJ. Extracapsular Cataract Surgery. St. Louis, USA:CV Mosby; 1983.p 98-99.  Back to cited text no. 13
Cruz OA, Wallace GW, Gay CA, Matoba Ay, Koch DD. Visual results and complications of phacoemulsification with intraocular lens implantation performed by ophthalmology residents. Ophthalmology 1992;99:448-52.  Back to cited text no. 14
Thomas R, Braganza A, Raju R, Lawrence, Spitzer KH. Phacoemulsification - A senior surgeon's learning curve. Ophthalmic Surg 1994;25:504-9.  Back to cited text no. 15
Charles S. Principles and techniques of vitreous surgery. In: Ryan SJ, editor. Retina. Vol 3:Surgical Retina. 2nd ed. St. Louis, USA:CV Mosby; 1994. p 2063-92.  Back to cited text no. 16
Wallace RT, McNamara JA, Brown G, Benson W, Belmont J, Goldberg R et al. The use of perfluorophenanthrene in the removal of intravitreal lens fragments. Am J Ophthalmol 1993;116:196-200.  Back to cited text no. 17
Fastenberg DM, Schwartz PL, Shaking JL, Golub BM. Management of dislocated nuclear fragments after phacoemulsification. Am J Ophthalmol 1991;112:535-59.  Back to cited text no. 18
Smiddy WE, Flynn HW Jr. Management of retained lens nuclear fragments and dislocated posterior chamber intraocular lenses after cataract surgery. Seminars in Ophthalmology 1993;8:96-103.  Back to cited text no. 19
Truhlsen SM. Approaching nuclear slippage, [correspondence] Arch Ophthalmol 1991;109:627.  Back to cited text no. 20
Schechter RJ. Glass slide vitrectomy for use by the cataract surgeon, [letter]. Am J Ophthalmol 1991;112:100.  Back to cited text no. 21
Gonvers M. New approach to managing vitreous loss and dislocated lens fragments during phacoemulsification. J Cat Ref Surg 1994;20:346-49.  Back to cited text no. 22
Michels RG, Shacklett DE. Vitrectomy technique for removal of retained lens material. Arch Ophthalmol 1977;95:1767-73.  Back to cited text no. 23
Rowson NJ, Bacon AS, Rosen PH. Perflourocarbon heavy liquids in the management of posterior dislocation of the lens nucleus during phacoemulsification. Br J Ophthalmol 1992;76:169-70.  Back to cited text no. 24
Movshovich A, Berrocal M, Chang S. The protective properties of liquid perflourocarbons in phacofragmentation of dislocated lenses. Retina 1994;14:457-62.  Back to cited text no. 25
Smiddy WE, Flynn HW Jr., Kim JE. Retinal detachment in patients with retained lens fragments or dislocated posterior chamber intraocular lenses. Ophthalmic Surg and Lasers 1996;27:856-61.  Back to cited text no. 26


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