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Capsulorrhexis in Capsular Delamination
Arch Ophthalmol. 2002;120:1581-1582.
INTRODUCTION
Separation of the anterior layer of the lens capsule, also known as true exfoliation and capsular delamination, has become an increasingly rare clinical finding. Although its pathogenesis is not precisely known, the condition has been associated with age, trauma, and exposure to toxins and/or to thermal radiation.1 An association with occupational infrared radiation exposure was accepted after Elschnig2 described the classic clinical findings in 2 glassblowers and Kubik3 and others4-5 noted the condition in blacksmiths, puddlers, chainmakers, and steelworkers. With improved safety standards, the condition is now reported less frequently in association with occupational hazards. Capsular delamination remains of interest particularly because there may be mild subclinical forms of the condition,6 and because modern cataract surgery is dependent on successful anterior capsule removal.
Report of a Case
An 81-year-old man who under treatment for a cardiac arrhythmia and hypertension reported blur and glare in both eyes. There was a family history of cataracts and glaucoma. His career involved more than 20 years in a steel mill. During 4 of these years, he experienced frequent and intense prolonged exposure to the heat of the blast furnaces.
On ophthalmic examination, his best-corrected visual acuity was 20/70 OU. The patient had hyperopia of 4 diopters. Bilateral cataracts were present, having combined cortical and nuclear elements. Within the central anterior chamber in both eyes was a folded cellophane-like membrane fixed to the anterior lens capsule's surface, unassociated with any evidence of inflammation (Figure 1). The degree of delamination was approximately symmetrical. There were no other abnormal deposits on the lens capsule or the iris, no unusual pigmentation of the angle, and no phacodonesis. Results of tonometry, fundus, and optic nerve examinations were all normal.
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Figure 1. Preoperative appearance of a diaphanous membrane (arrows) in the anterior chamber that is attached to the lens.
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The patient underwent bilateral cataract extraction with a 2-month interval between procedures. The phacoemulsification technique was standard except for a larger than usual capsulorrhexis and the submission of the capsule specimens for histopathologic study. The diaphanous membrane was gently teased to the side and the deeper capsular layer was dissected with a bent 30-gauge needle. There were no complications in either operation. Two years postoperatively, the uncorrected vision was 20/25 OU with a mild astigmatism with the rule noted on refraction. The posterior capsules remained clear and the anterior capsular edges appeared normal.
Findings from the histopathologic examination of the specimens revealed delamination of the lens capsule that was best illustrated by transmission electron microscopy (Figure 2). The capsule was moderately electron dense with a laminated granular appearance. The splitting of the capsule was documented with the anterior layer thinner than the posterior layer.
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Figure 2. Electron microscopy ultrastructural appearance of a 3-µm-thick layer (asterisk) that is split from the anterior lens capsule. Note surface-parallel vacuolization of the anterior capsule extending beyond the split (original magnification x12 000).
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Comment
Multiple reports exist of capsular delamination specimens from successful intracapsular and extracapsular cataract surgery.4, 7-8 In this case, the curvilinear capsulorrhexis technique was successful. With the exception of the manipulation required to take the surgical specimen, the cases were routine and without complication. To our knowledge, no series to date has reported a rate of complication in cataract extraction with capsular delamination, but the true incidence of complications associated with this finding will be difficult to establish because of its rarity.
While capsular delamination is rare, mild and subclinical forms of the condition may be more prevalent than currently recognized. In a series of 10 cases, Wollensak and Wollensak6 reported the appearance of a double contour visible at the capsulorrhexis edge. Pathologic analysis of the capsulorrhexis specimens by light and electron microscopy revealed the double contour to result from a characteristic step formation at the capsulorrhexis edge. In 7 of 10 of these cases, these authors also noted surface-parallel splits in the outer third of the capsule. They postulated that the double contour and microscopically evident surface-parallel splits may represent a subclinical form of true exfoliation that results from zonular traction on the superficial capsule over less elastic deeper layers in older patients. These findings suggest that true exfoliation may represent one extreme of a continuum representing different degrees of capsular delamination. Although Wollensak and Wollensak reported anecdotally that the incidence of radial capsular tears appeared lower when a double contour was seen, no evidence currently exists regarding the relative strength or weakness of the capsulorrhexis with the double contour. Likely, the finding goes unnoticed in most cases. No double contour was observed after curvilinear capsulorrhexis in our case. Perhaps this is because the delamination did not extend to the capsulorrhexis edge, although evidence for shearing of the capsular layers beyond the edge of true exfoliation is suggested by the vacuolization of the capsule seen ultrastructurally beyond the split (Figure 2).
Although associations with trauma, toxins, inflammation, and heat are well recognized, the underlying etiology of true exfoliation of the lens capsule remains uncertain. Small case series of patients without a history of trauma or heat exposure suggest aging may be a major factor.9 It has also been suggested that capsular protein abnormalities may play a role.10 In this case, however, a volunteered history of prolonged exposure to the heat of a blast furnace provided the most likely etiologic factor related to both the cataract and delamination of the anterior capsule. Clinically, diaphanous transparent membranes were similar to those reported as glassblower's cataracts. Fortunately, occupational safety standards and protective engineering have made true exfoliation from infrared exposure rare.
AUTHOR INFORMATION
The authors have no financial interest in this article.
James S. Kelley, MD;
Tony Tsai, MD;
Mary B Kansora, MD;
W. Richard Green, MD
Baltimore, Md
Corresponding author: James S. Kelley, MD, 6565 N Charles St, Suite 302, Baltimore, MD 21204 (e-mail: jimkell{at}aol.com).
REFERENCES
1. Duke-Elder S. System of Ophthalmology: Diseases of the Lens and Vitreous; Glaucoma and Hypotony. St Louis, Mo: CV Mosby; 1969.
2. Elschnig A. Abhlösung der Zonulalamelle bei Glasblasern. Klin Monatsbl Augenheilkd. 1922;69:732-734.
3. Kubik J. Ablösung der zonulalamelle bei Glasblasern. Klin Monatsbl Augenheilkd. 1923;70.
4. Burde RM, Bresnick G, Uhrhammer J. True exfoliation of the lens capsule: an electron microscopic study. Arch Ophthalmol. 1969;82:651-653.
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5. Holloway TB, Cowan A. Concerning lamellar membranes of the anterior surface of the lens. Am J Ophthalmol. 1931;14:189-195.
6. Wollensak G, Wollensak J. Double contour of the lens capsule edges after continuous curvilinear capsulorhexis. Graefes Arch Clin Exp Ophthalmol. 1997;235:204-207.
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7. Fukuo Y, Takeda N, Hirata H, et al. Histological findings of capsular delamination of the lens. Jpn J Ophthalmol. 1994;38:87-91.
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8. Kuchle M, Iliff WJ, Green WR. Kombinierte Feuerlamelle und Pseudoexfoliation der vorderen Linsenkapsel. Klin Monatsbl Augenheilkd. 1996;208:127-129.
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9. Cashwell LF Jr, Holleman IL, Weaver RG, van Rens GH. Idiopathic true exfoliation of the lens capsule. Ophthalmology. 1989;96:348-351.
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10. Anderson IL, van Bockxmeer FM. True exfoliation of the lens capsule: a clinicopathological report. Aust N Z J Ophthalmol. 1985;13:343-347.
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SECTION EDITOR: W. RICHARD GREEN, MD
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