Early-Onset Posterior Polymorphous Dystrophy

Confocal Microscopy of Posterior Polymorphous Endothelial Dystrophy

“…Chiou The ultrastructural features of PPED have been described as a round ''nest'' of abnormal cells surrounded by normal endothelial cells. 6 Similar features were also present in our cases. Vesicular lesions on the endothelial layer were observed in all the diseased eyes.…”

Missense mutations in COL8A2, the gene encoding the alpha2 chain of type VIII collagen, cause two forms of corneal endothelial dystrophy

“…2). The secretion of an abnormal PCL containing type VIII collagen has also been demonstrated in aphakic bullous keratopathy and the ICE syndromes (3,15,35) suggesting that alteration of its expression and deposition may be relevant to the pathological responses of the endothelium to ageing and trauma. Moreover, as type VIII collagen is a component of other endothelial basement membranes, including those of vascular endothelia, understanding the interaction of the corneal endothelium with both DM and type VIII collagen may provide a broader insight into endothelial cell maintenance and ageing.…”

In Vivo Confocal Microscopy of Posterior Polymorphous Dystrophy

“…[9][10][11] Focal areas may be devoid of endothelial cells. 12 Some studies have reported areas of thinning in Descemet's membrane 9,11 and most have shown abnormal lamination with deposition of collagenous material between laminae. [10][11][12] Unfortunately, histologic studies have only been performed on corneal buttons after penetrating keratoplasty and therefore represent only severe cases of PPD with corneal edema.…”

“…12 Some studies have reported areas of thinning in Descemet's membrane 9,11 and most have shown abnormal lamination with deposition of collagenous material between laminae. [10][11][12] Unfortunately, histologic studies have only been performed on corneal buttons after penetrating keratoplasty and therefore represent only severe cases of PPD with corneal edema. Both specular and confocal microscopy enable imaging of the cornea in vivo and may be used to examine earlier or mild cases that represent the most common form of PPD.…”