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Multirecurrence of corneal posterior polymorphous dystrophy. An ultrastructural study
W Sekundo1, W R Lee, D A Aitken
1Tennent Institute of Ophthalmology, Western Infirmary, Glasgow, Scotland.
Cornea
|November 1, 1994
Summary
Posterior polymorphous corneal dystrophy (PPD) involves an abnormal endothelium and Descemet's membrane thickening. This study found host endothelium repopulated donor corneas, with a fibrocellular layer forming at the periphery, not from the endothelium itself.
Area of Science:
- Ophthalmology
- Corneal Diseases
- Histopathology
Background:
- Posterior polymorphous corneal dystrophy (PPD) is a rare, inherited corneal disease.
- Characterized by an epithelium-like corneal endothelium and thickening of Descemet's membrane by a posterior collagenous layer (PCL).
- Reepithelialization of posterior cornea in donor tissue is exceptionally rare.
Observation:
- Examined three corneal buttons from a patient with bilateral PPD using light and electron microscopy.
- Investigated donor corneas after 3 and 4 years post-keratoplasty.
- Assessed the morphology and composition of the posterior collagenous layer and endothelium.
Findings:
- Host epithelium-like endothelium repopulated the posterior surface of donor corneas.
- Posterior collagenous layer (PCL) was absent centrally but present peripherally in failed grafts.
- Peripheral PCL was fibrocellular, distinct from the fibrillar PCL in the initial graft, suggesting host fibrous ingrowth.
Implications:
- The epithelium-like endothelium's synthetic capacity is limited, similar to corneal epithelium, not native endothelium.
- Host fibrous ingrowth, not the epithelium-like endothelium, is the primary contributor to the fibrocellular PCL in repeat keratoplasties.
- Understanding PPD pathogenesis aids in managing corneal transplantation outcomes.