[Myopia in pseudoxanthoma elasticum]

Refraction in patients with pseudoxanthoma elasticum (PXE) has not yet been studied in the literature. The purpose of our study was to determine if PXE may be associated with myopia, similarly to Marfan syndrome, another collagen-vascular disease.

This cross-sectional study evaluated 53 consecutive patients (32 women and 21 men, mean age 50 ± 16) from September 2009 to June 2011, with 53 age- and sex-matched controls. For each patient, we measured spherical equivalent, visual acuity, keratometry, axial length and crystalline lens power of each eye. Results were compared with Student's t-test.

There was a significant difference between the mean values of myopia in the PXE population (-0.98) compared to the group of healthy controls (-0.33, P<0.0093). There was no significant difference between the two groups for the axial length (23.9 mm versus 23.69 mm; P=0.236), keratometry (43.53 versus 43.44; P=0.68), lens power (22.03 versus 21.71; P=0.225).

PXE induces calcification of elastic fibers in various human tissues (skin, retina, vascular walls). Since there are no elastic fibers in the cornea or lens, we assume that the elastic zonular fibers may be pathologic in PXE patients. This could result in an anterior displacement of the lens in PXE, which could explain the moderate myopia.

PXE may be associated with mild myopia compared to healthy controls. Additional studies, including more patients and evaluating anterior chamber depth and zonular histology are necessary to confirm these preliminary findings.