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Year : 2002  |  Volume : 50  |  Issue : 2  |  Page : 140-142

"String of Pearls" following Nd:YAG laser posterior capsulotomy

L. V. Prasad Eye Institute, L.V. Prasad Marg, Banjara Hills, Hyderabad-500 034, India

Correspondence Address:
S Chatterjee
L. V. Prasad Eye Institute, L.V. Prasad Marg, Banjara Hills, Hyderabad-500 034
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Source of Support: None, Conflict of Interest: None

PMID: 12194574

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Posterior capsular re-opacification can occur following Nd-YAG capsulotomy. This necessitates multiple capsulotomies with its potential complications. We report one such case and discuss possible predisposing factors and preventive measures for this condition

Keywords: Posterior capsule reopacification, Nd: YAG capsulotomy, string of pearls

How to cite this article:
Chatterjee S, Garg P. "String of Pearls" following Nd:YAG laser posterior capsulotomy. Indian J Ophthalmol 2002;50:140-2

How to cite this URL:
Chatterjee S, Garg P. "String of Pearls" following Nd:YAG laser posterior capsulotomy. Indian J Ophthalmol [serial online] 2002 [cited 2020 Oct 20];50:140-2. Available from: https://www.ijo.in/text.asp?2002/50/2/140/14803

Posterior capsule opacification is the most common complication of extracapsular cataract surgery, requiring treatment in up to 50% of patients by 3 years.[1] For the past two decades, Nd: YAG laser posterior capsulotomy has been the preferred mode of treatment for any opacification of the posterior capsule.[2],[3] This is an out patient procedure that clears the visual axis and improves vision instantaneously, and is not associated with the complications of intraocular surgery. However, a small percentage of patients develop reopacification of the posterior capsule opening after initial successful Nd: YAG capsulotomy.[4],[5] We report one such case.

  Case report Top

A 48-year-old diabetic male underwent phacoemulsification with posterior chamber intraocular lens (PCIOL) implantation in the right eye for senile cataract in 1998. The surgery was uneventful. He was implanted with a single piece, biconvex, all PMMA (polymethyl methacrylate) intraocular lens. The optic diameter was 5.5 mm and the over all diameter was 12 mm. The capsulorhexis was overlapping the optic edge all around at the conclusion of the surgery. The postoperative course was uneventful and at five weeks follow-up the visual acuity in the operated eye was 6/9 with -1.0 diopter cylinder at 90.

Two years later the patient presented to us with complaints of glare and blurring of vision in the same eye of 4 months duration. He had undergone Nd: YAG capsulotomy elsewhere 8 months before, after which the vision was satisfactory. On examination the unaided and best-corrected visual acuity was 6/9. The anterior segment was within normal limits. The capsulorhexis edge was overlapping the intraocular lens all around [Figure - 1]. The posterior capsule had a central opening measuring 3mm in the widest area. The edge of the opening showed large balloon shaped cells attached to each other and extending into the opening from all sides [Figure - 2]. Remaining posterior capsule showed Elschnig's pearls. Fundus examination showed features of non-proliferative diabetic retinopathy. The patient was diagnosed t o having narrowing of the posterior capsule opening and was managed by a repeat Nd: YAG capsulotomy.

  Discussion Top

Continuous tear capsulorhexis, with its many advantages, is the preferred method of anterior capsulotomy. But certain untoward results have also been observed; these include capsular bag hyperdistention, shrinkage of anterior capsular opening, and epithelial cell hyperproliferation on the posterior capsule.[5] This hyperproliferation of lens epithelial cells may occur even after laser posterior capsulotomy causing narrowing of the opening and resulting in visual disturbances, as seen in our case.

The reported incidence of posterior capsular reopacification is 0.7%.[4] Masket, coined the term "string of pearls" for these balloon shaped cells proliferating around the capsulotomy reducing the size of capsular opening.[5] These pearls appear to form on the anterior hyaloid and capsulotomy edge using either of these as scaffold and then progressing centrally.

This complication seems to appear less often in the paediatric population when primary surgical posterior capsulotomy and anterior vitrectomy is performed.[6] Possibly with the removal of the anterior vitreous face, the scaffold for the cell migration is removed. This discourages reopacification of the posterior capsule. Jamal and Solomon,[7] showed that patients below 50 years of age were twice as likely to develop pearls following lens removal. The patient reported by us also belongs to the same age group. Lens epithelial cells in the young are more juvenile and are less affected by the contact inhibition of the intraocular lens or by other substances, and have a greater propensity of proliferation.

Jones et al,[8] reported proliferation of lens epithelial cells after Nd: YAG laser posterior capsulotomy in patients with proliferative vitreoretinal diseases, including proliferative diabetic retinopathy. They pointed to the role of growth factors in the initiation and perpetuation of the lens epithelial proliferation. The disruption of the capsule may result in the growth factors bathing the lens epithelial remnants and stimulating them. Our patient had non-proliferative diabetic retinopathy; therefore, the possibility of such factors causing re-opacification of the capsule appears remote.

The "string of pearls" is noted with PMMA, hydrogel, and silicon intra-ocular lenses (IOL) and the phenomenon is not related to a particular IOL material. Masket,[5] observed this phenomenon in cases where the IOL diameter exceeded the anterior capsulorhexis; a similar situation existed in our case. Although the causes and significance of long-term unchecked proliferation of lens epithelial cells is poorly understood, continued cell growth may necessitate multiple capsulotomies in the same eye. Each laser treatment is likely to increase the risk of potential complications. An anterior capsulorhexis larger than the optics of the IOL, such that the capsular leaflets can fuse may eliminate this problem. Developments of methods to eliminate lens epithelial cells at the time of cataract surgery could also prevent this complication.

  References Top

Apple DJ, Solomon KD, Tetz MR, Assia EI, Holland EY, Legler UF, et al. Posterior capsular opacification. Surv Ophthalmol 1992;37:73-116.  Back to cited text no. 1
Aron-Rosa D, Aron J-J, Griesemann M, Thyzel R. Use of the Neodymium YAG laser to open the posterior capsule after lens implant surgery: a preliminary report. J Am Intraocul Implant Soc 1980,6:352-54.  Back to cited text no. 2
Terry AC, Stark WJ, Maumenee AE, Fagadau W. Neodymium YAG laser for posterior capsulotomy. Am J Ophthalmol 1983,96:716-20.  Back to cited text no. 3
Roger JE, McPherson BM, Govan AA. Posterior capsule opacification after Neodymium YAG laser capsulotomy. J C a t Refract Surg 1995,21:351-52.  Back to cited text no. 4
Masket S. Postoperative complications of capsulorhexis. J Cat Refract Surg 1993,19:721-24.  Back to cited text no. 5
Hutcheson KA, Drack AV, Ellish NJ, Lambert SR. Anterior hyaloid face opacification of the pediatric Nd: YAG laser posterior capsulotomy. J AAPOS 1999, 3:303-7.  Back to cited text no. 6
Jamal SA, Solomon LD. Risk factors for posterior capsule pearling after uncomplicated extra-capsular cataract extraction and plano-convex posterior chamber lens implantation. J Cat Refract Surg 1993;19:333-38.  Back to cited text no. 7
Jones NP, McLeod D, Boulton ME. Massive proliferation of lens epithelial remnants after Nd: YAG laser capsulotomy. B r J Ophthalmol 1995;79 261-63.  Back to cited text no. 8


  [Figure - 1], [Figure - 2]

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