Confocal microscopy identification of keratoconus associated with posterior polymorphous corneal dystrophy

Abstract

We present a case of keratoconus in which the association with posterior polymorphous corneal dystrophy was established by confocal microscopy. Confocal microscopy enable us to assess the differential diagnosis between posterior corneal dystrophies, essential for a prognosis and therapeutic decision.

Corneal thickness changes after corneal collagen crosslinking for keratoconus and corneal ectasia: One-year results

“…However, the continued decrease in corneal thickness from 1 to 3 months suggests other causes of the changes in corneal thickness. Anatomic and structural changes in corneal collagen fibrils, such as compression of collagen fibrils (especially the more transverse-oriented anterior fibrils), 10,23 changes in corneal hydration 24 and edema, 25,26 keratocyte apoptosis, 13,27,28 and changes in glycosaminoglycans 29 might be implicated.…”

“…39 However, the decrease in pachymetry found in this study could be an artifact of inaccurate measurement by the Pentacam system as a result of the postoperative corneal haze, 39,40 typically seen clinically after CXL. 4,5,9,13,28 Indeed, difficulty measuring post-CXL pachymetry has been reported using the Orbscan scanning-slit topography device (Bausch & Lomb). 4 However, in contrast to postoperative Orbscan measurements, Pentacam and ultrasound pachymetry measurements are found to be similar after PRK, despite the corneal haze inherent in that procedure.…”

Classification of Posterior Polymorphous Corneal Dystrophy as a Corneal Ectatic Disorder Following Confirmation of Associated Significant Corneal Steepening

“…7–20 While the association of PPCD with keratoconus was initially reported in the English-language literature almost 40 years ago, the subsequent 9 reports of this association published between 1989 and 2010 consisted of either individual case reports (4) or small case series (3, 3, 4, 5 and 7 subjects). 7, 8, 10–15, 18, 20 Given the relative frequency of keratoconus in the general population, estimated to have an incidence of 1 in 2000, as well as its reported association with a variety of ocular and non-ocular disorders, the significance of the reported association with PPCD has been questioned. 21 However, mutations in the visual system homeobox gene 1 ( VSX1 ; MIM #605020) have been implicated as playing a pathogenic role in both PPCD and keratoconus, thus providing support to the contention that the reported association between the disorders is more than just coincidental.…”

Phenotypic Spectrum of Granular Corneal Dystrophy Type II in Two Italian Families Presenting an Unusual Granular Corneal Dystrophy Type I Clinical Appearance

“…IVCM analysis [8, 9] provided an interesting insight in the microstructure of the deposits showing a mix of granular hyaline deposits associated with circular fusiform or linear deposits, maybe of amyloid origin, starting at sub-Bowman layers and involving the anterior-mid stroma until 300–350  μ m of depth. These morphological findings justified another alternative name given in the past to GCD2 as combined Granular-Lattice Corneal Dystrophy although the amyloid component is typically only apparent by histopathology and does not resemble lattice lines.…”