Bilateral Keratoconus In A Patient With Confirmed Pseudoxanthoma Elasticum

Although 97% of keratoconus cases are isolated, an estimated 3% are related to diseases that affect multiple organs throughout the body, such as Down Syndrome, Ehlers-Danlos syndrome and Osteogenesis Imperfecta. We present a case of a patient with the autosomal recessive heritable connective tissue disorder pseudoxanthoma elasticum (PXE), who, in addition to the to characteristic PXE retina findings (choroidal neovascularization [CNV], Angiod streaks [AS]) also presented with bilateral keratoconus.

ELZA Institute, Zurich, Switzerland

A 64-year-old female with PXE, diagnosed 12 years previously was referred to us because of abnormal findings in both corneas. A retina specialist had treated CNV secondary to AS with intravitreal anti-VEGF since diagnosis.

Patient’s CDVA was <0.1 OD and 0.32 OS. Subjective refractions were -8.25sph -2.50cyl @ 101° (OD) and -6.00sph -1.25cyl @ 73° (OS). Slit lamp and fundus examinations revealed no ectasia, normal optic discs (C/D ratio 0.2), and bilateral macular scarring.

Corneal tomography revealed bilateral keratoconic irregular astigmatism. The thinnest point of the cornea and Kmax being 464µm and 55.1 D (OD) and 501 µm and 46.8 D (OS). Rigid gas-permeable lenses improved vision from <0.1–0.40 OD and 0.32–0.80 OS. No ectasia progression was observed at follow-up visits.

 

Patients with noninflammatory connective tissue diseases like PXE who present for an eye examination should not simply be examined for retinal pathologies, but also be carefully examined with a corneal tomographer for the presence of changes in corneal shape like corneal ectatic disease.