|LETTER TO EDITOR
|Year : 2006 | Volume
| Issue : 3 | Page : 215-216
Ultrastructural study of a contusion cataract
Koray Gumus1, Hayyam Kiratli1, Sinan Yuruker2
1 Department of Ophthalmology, Hacettepe University School of Medicine, Ankara, Turkey
2 Department of Histology, Hacettepe University School of Medicine, Ankara, Turkey
Department of Ophthalmology, Hacettepe University School of Medicine, Ankara
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Gumus K, Kiratli H, Yuruker S. Ultrastructural study of a contusion cataract. Indian J Ophthalmol 2006;54:215-6
Ocular blunt trauma may damage the lens epithelium and capsule, creating a rosette-shaped anterior/posterior subcapsular opacification of cortical lens fibers., In our case, we provide new ultrastructural features of a contusion cataract, which may further shed light onto the possible physiopathologic mechanisms for its development.
A 48-year-old man with a history of blunt trauma, presented with blurred vision in his right eye. Rosette-shaped anterior and posterior subcapsular opacifications [Figure - 1] and accompanying lens subluxation and phacodonesis, led to an intracapsular cataract extraction followed by anterior vitrectomy, sector iridectomy and IOL implantation. The lens material was analyzed by light and electron microscopy. Light microscopy showed an anterior subcapsular cataract with a prominent depression in the centre of the anterior lens capsule. In this area, the normal regular one layer cellular arrangement was largely disrupted. Electron microscopy documented that in the anterior subcapsular region, the lens epithelium was replaced by multilayered fibrous plaque and different cell types were dispersed, with marked intercellular cyst formations. Two prominent cell types were observed; one with a cytoplasm with moderate density having a euchromatic nucleus and a second degenerated type with an electron-dense cytoplasm and vacuoles [Figure - 2]. While normal appearing cells had few organelles [Figure - 3], degenerated cells had no obvious organelles and their nuclei were ondulated, with coarse chromatin distribution. These were squamous in shape and were scattered among neighboring normal appearing cells which usually formed clusters, possibly indicating a tendency for proliferation [Figure - 4]. No abnormality was documented in the superficial lens fibers [Figure - 5].
The diagnostic feature of a contusion cataract is a circumscribed rosette-shaped opacity of the lens, in association with the suture system. With the development of new clear lens fibers, the opacifications increase in density and become separated from the subcapsular zone. At the early stage of injury, lens opacity shows a superficial zone of swollen lens fibers, which are irregular in size, shape and cytoplasmic density. In the course of time, these swollen fibers undergo degeneration and shrinkage, remaining as cytoplasmic and membranous remnants within large intercellular cystic spaces between normal flattened fiber cells. This alteration may lead to the formation and accumulation of prominent intercellular cavities. In the outer layers, the cell swelling and breakdown may be due to osmotic effects. It has been postulated that dysfunction of the ion pump mechanisms in the lens epithelial cells, which have important roles in the active uptake of ions, myo-inositol and other constituents of the lens, lead to an influx of aqueous into the lens tissue, subsequently leading to swelling and damage of cortical fiber cells similar to that occurring in late-onset diabetics. Eventually, in the late course of a cataractous lens, vacuolic appearance occurs due to degeneration of these swollen lens fibers.
Consequently, the ultrastructural findings of our case support the pivotal role of the lens epithelium in the self-repair mechanisms of the lens, following blunt trauma. The mitotic activity of the epithelium may represent efforts to contain the damage resulting from acute disruption of the one-cell-layer normal epithelium.
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]