Intravitreal bevacizumab (Avastin) for choroidal neovascularisation secondary to pathological myopia: 6-month results.

BACKGROUND: To determine the efficacy and safety of intravitreal Avastin (bevacizumab) in the treatment of choroidal neovascularisation (CNV) secondary to pathological myopia (PM). METHODS: This paper reports on a consecutive prospective study of patients with CNV secondary to PM who were treated with intravitreal bevacizumab (1.25 mg/0.05 ml). Patients underwent complete ophthalmic evaluation, which included best-corrected visual acuity testing measured with Early Treatment Diabetic Retinopathy Study charts, optical coherence tomography (OCT), and fluorescein angiography. RESULTS: There were 17 eyes of 17 patients, and the mean age was 55.4 (SD 10.0) years. At the 6-month follow-up, the mean visual acuity improved by 8.4 letters (p = 0.04). Forty-one per cent of patients increased at least one line, and 17% increased more than six lines. There were no cases of moderate vision loss (>or=3 lines) or severe vision loss (>or=6 lines). The mean OCT foveal thickness decreased by 79.6 mum (p = 0.002). Favourable outcomes were obtained in all subgroups. Patients received an average of one injection. As a complication, there was a tear of the retinal pigment epithelium. No other ocular or systemic side effects were observed. CONCLUSION: In our study, intravitreal bevacizumab appeared to be safe and efficacious in eyes with CNV secondary to PM.

Scaling exponents for fracture surfaces in homogeneous glass and glassy ceramics.

We investigate the scaling properties of postmortem fracture surfaces in silica glass and glassy ceramics. In both cases, the 2D height-height correlation function is found to obey Family-Viseck scaling properties, but with two sets of critical exponents, in particular, a roughness exponent zeta approximately 0.75 in homogeneous glass and zeta approximately 0.4 in glassy ceramics. The ranges of length scales over which these two scalings are observed are shown to be below and above the size of the process zone, respectively. A model derived from linear elastic fracture mechanics in the quasistatic approximation succeeds to reproduce the scaling exponents observed in glassy ceramics. The critical exponents observed in homogeneous glass are conjectured to reflect the damage screening occurring for length scales below the size of the process zone.

Glass breaks like metal, but at the nanometer scale.

We report in situ atomic force microscopy experiments which reveal the presence of nanoscale damage cavities ahead of a stress-corrosion crack tip in glass. Their presence might explain the departure from linear elasticity observed in the vicinity of a crack tip in glass. Such a ductile fracture mechanism, widely observed in the case of metallic materials at the micrometer scale, might be also at the origin of the striking similarity of the morphologies of fracture surfaces of glass and metallic alloys at different length scales.