Alterations of the anterior lens capsule with associated climatic droplet keratopathy have been reported in elderly individuals exposed to ultraviolet light. These alterations vary in severity from mild forms like frosting and plateau formation which are more common, to a severe herniation also known as a 'bag' or bagging of the anterior lens capsule which is rare.12 Capsular herniation can be mistaken for an anterior lenticonus in which both the capsule and the cortex bulge forward. The exact pathology behind this finding is still unclear.
We report the clinical, ultrasound biomicroscopy (UBM) and histopathological findings of a case of herniation of the anterior lens capsule. UBM was done to differentiate this condition from anterior lenticonus and histopathology to determine the exact capsular abnormality in the area of herniation.
A 75-year-old male farmer residing in rural Tamil Nadu was screened at a camp and brought to the base hospital for cataract surgery. The best corrected visual acuity was finger counting at two meters in his right eye and one meter in the left eye. Slit-lamp examination revealed spheroidal degeneration (Grade III),3 in both eyes with associated iris atrophy and pseudoexfoliation along the pupillary ruff. In addition, the left eye of the patient had a shallow anterior chamber with herniation of the anterior lens capsule in the pupillary area and phacodonesis. The region of capsular herniation had a clear fluid-filled space between its anterior and posterior layer [Fig. 1A]. The intraocular pressure was normal in both the eyes. Gonioscopy in the left eye revealed a narrow angle with bowing of the iris; pseudoexfoliative material was visible over the peripheral iris. An UBM (OTI/UBM, HF 35-50, Ontario, Canada) was performed and revealed a clear cyst of the anterior lens capsule measuring 0.92 mm x 2.03 mm (height and breadth) [Fig. 1B]. However, the underlying cortex did not show a forward herniation. There was no evidence of a scolex within the cyst. The angle measured 16.8 degrees and there was bowing of the peripheral iris.
Due to the advanced cataract, gross phacodonesis and spheroidal degeneration, phacoemulsification was not performed and the patient underwent extracapsular cataract extraction in the left eye.
At the start of surgery, the cyst fluid was aspirated through a temporal paracentesis. The anterior lens capsule specimen obtained at the time of capsulotomy (envelope) was collected and sent for histopathological evaluation. The surgeon noted friability of the anterior capsule. The remaining surgical steps were uneventful. Due to severe zonular weakness and spheroidal degeneration, the patient was left aphakic.
The anterior lens capsule specimen was processed in alcohol and embedded in paraffin wax. Samples of 5 mm thickness were stained with hematoxylin and eosin and observed under oil immersion (total magnification 1000x).
The specimen revealed a split in the anterior capsule at the site of herniation, into an outer thicker and inner thinner layer, the remaining anterior capsule revealed superficial partial splits on its surface [Fig. 2A and B]. Cyst fluid analysis did not reveal any cells.
Exposure to ultraviolet light has been linked to the development of climatic droplet keratopathy, exfoliation syndrome and cataract,45 as well as alterations in the anterior lens capsule.12 As the basement membrane of the lens epithelial cells, the lens capsule is one of the thickest such membrane in the body and still has sufficient selective permeability to allow nourishment and protection of the enclosed lens. In 1922, Elschnig reported peeling of the central anterior capsule in glass blowers exposed to high degrees of heat.6 There have been several reports of true exfoliation associated with other conditions like iridocyclitis, trauma and increased age (senile exfoliation).7 This entity was originally called capsular exfoliation and later renamed true exfoliation by Dvorak-Theobald to distinguish it from psuedoexfoliation.8 Brodrick suggested the term capsular delamination to describe the condition better.7 The delaminated portion of the capsule may split and yet maintain its attachment to the capsule at one end or may separate entirely and come to lie in the anterior chamber. Clinical appearance of true exfoliation is like that of a scroll or a cellophane sheet or a diaphanous membrane in front of the lens. The ultrastructural finding of such a capsule reveals a split into an anterior and posterior layer.910 The pathology behind capsular delamination is still obscure. The possibility of heat-activated proteolysis has been suggested as a cause of capsular delamination by Anderson et al.9 Brodrick et al. proposed cellular abnormality as a potential underlying cause of scrolling.7
Histopathology in our patient clearly revealed a split in the capsule in the area of herniation as well as partial splits of the surrounding capsule suggestive of diffuse capsular delamination. Cyst formation could be one of the presentations of capsular delamination with aqueous collection within it. Herniation of the anterior lens capsule must be differentiated from anterior lenticonus where both, the capsule and cortex bulge forward, not merely the capsule. UBM is useful when visibility is hampered by the presence of corneal conditions like spheroidal degeneration. Because of the extreme friability, care has to be taken in such patients when handling the anterior capsule during anterior capsulotomy. To our knowledge the UBM and histopathological findings of herniation of the anterior lens capsule have not been reported in the past.
The strong association of climatic droplet keratopathy and herniation of the anterior capsule with exposure to ultraviolet light could implicate it as a cause of diffuse capsular delamintion with cyst formation unlike true exfoliation caused by infrared radiation which is membranous and localized.
Our sincere gratitude to Dr. Jeena Mascarenhas (Cornea Consultant) for her guidance during the preparation of this case report.
1. J ohnson G, Minassian D, Franken S. Alterations of the anterior lens capsule associated with climatic keratopathy Br J Ophthalmol. 1989;73:229–34
2. Johnson GJ, Green JS, Paterson GD, Perkins ES. Survey of ophthalmic conditions in a Labrador community: II. Ocular disease Can J Ophthalmol. 1984;19:224–33
3. Johnson GJ. Aetiology of spheroidal degeneration of the cornea in Labrador Br J Ophthalmol. 1981;65:270–83
4. Resnikoff S, Filliard G, Dell'Aquila B. Climatic droplet keratopathy, exfoliation syndrome and cataract Br J Ophthalmol. 1991;75:734–6
5. Taylor HR. The environment and the lens Br J Ophthalmol. 1980;64:303–10
6. Elschnig A. Detachment of the zonular lamellae in glassblowers Klin Monastsbl Augenheilkd. 1922;69:732–4
7. Brodrick JD, Tate GW Jr. Capsular delamination (true exfoliation
) of the lens. Report of a case Arch Ophthalmol. 1979;97:1693–8
8. Dovorak-Theobald GD. Pseudo exfoliation of lens capsule: Relation to true exfoliation
Am J Ophthalmol. 1954;37:1–12
9. Anderson IL, van Bockxmeer FM. True exfoliation
of the lens capsule. A clinicopathological report Aust NZJ Ophthalmol. 1985;13:343–7
10. Karp CL, Fazio JR, Culbertson WW, Green WR. True exfoliation
of the lens capsule Arch Ophthalmol. 1999;117:1078–80