Posterior Corneal Steepening in Posterior Polymorphous Corneal Dystrophy

The aim was to evaluate the anterior and posterior corneal topographic characteristics of three patients with posterior polymorphous corneal dystrophy (PPCD) using a rotating Scheimpflug camera combined with a Placido disc system (Sirius, CSO, Italy).

Two children with unilateral PPCD and a 53-year-old woman with bilateral PPCD were diagnosed by the presence of vesicles and railroad track lesions at the level of the Descemet membrane with slitlamp biomicroscopy and in vivo confocal microscopy. Anisometropic and/or meridional amblyopia was detected in both children. In the 16-year-old child, there was unilateral anterior corneal steepening with high astigmatism (plano -7.00 x 170) in the eye with PPCD. The 5-year-old boy had unilateral axial myopia and against-the-rule corneal astigmatism (-12.00 -2.00 x 90). Corneal topography of the woman revealed with-the-rule astigmatism and thin corneas (464 μm OD and 445 μm OS) in both eyes. Posterior corneal steepening greater than 25 μm either in a vertical or in a horizontal pattern changing with the orientation of the railroad track band lesions was detected in all subjects.

Besides anterior corneal changes, PPCD seems to cause posterior corneal elevation, which necessitates corneal tomographic evaluation. In unilateral or highly asymmetric cases, children with PPCD should be screened for amblyopia.