Measurement of scleral rigidity in patients with age‐related macular degeneration

Abstract

AbstractPurpose It has been hypothesized that altered mechanical properties of the sclera may contribute to the pathogenesis of age‐related macular degeneration. Unfortunately, the determination of structural stiffness of the sclera in vivo is difficult. In this study, we present a new technique to estimate sclera stiffness in vivo. In addition, we aim to test the hypothesis that sclera stiffness is altered in patients with AMD.Methods 44 patients with AMD and 22 healthy subjects, matched for age, sex and intraocular pressure were included in the study. Ocular pulse amplitude(PA) and pulsatile ocular blood flow were assessed using pneumotonometry. Ocular fundus pulsation amplitude(FPA) was measured by the means of laser interferometry. A coefficient for ocular rigidity(E1), based on the Friedenwald equation was calculated relating PA/FPA, as a measure for structural stiffness.Results FPA was decresased in patients with AMD when compared to the healthy group (p = 0.025). However, no difference was observed PA between patients with AMD and healthy subjects ( p = 0.34). E1 was significantly higher in the patients with AMD (0.91 ± 0.11AU) than in the control subjects (0.70 ± 0.07AU; p < 0.001).Conclusion Our data indicate that the mechanical properties of the sclera are different in patients with AMD compared to healthy subjects. In particular, our data indicate an increased sclera stiffness in the AMD group. Whether this causatively involved in the pathogenesis of AMD or a consequence of the disease, has yet to be shown.