purpose : to report a rare case of large vascularized astrocytoma on optic disc. case report : a 12-year-old boy with history of decreased vision in the left eye since 5-6 months ago was referred to the ocular oncology service at rassoul akram hospital with provisional diagnosis of retinoblastoma. on examination, visual acuity was counting fingers at 50 cm, and a 3+ relative afferent pupillary ...

An in vitro test for the development of corneal opacity in response ocular irritants was first proposed by Muir (1984). This test required the clamping of a bovine cornea between two chambers filled with physiologic saline and measuring the transmittance of white light through the cornea using the voltage output of a photocell. This was followed by exposure of the epithelial surface of the corn...

This paper presents an advanced patterned vertical aligned nematic liquid crystal (APVA) mode as a way of improving the transmittance of the conventional patterned, vertically-aligned nematic liquid crystal (PVA) mode. The APVA was characterized by multi-electrodes, which play an important role in generating a horizontal electric field that prevents LC disclination in the vicinity of the middle...

Graphene oxide (GO) emerges as a functional material in optoelectronic devices due to its broad spectrum response and abundant optical properties. In this article, it is demonstrated that the change of optical transmittance amplitude for monolayer GO (mGO) could be up to 24.8% by an external electric field. The frequency harmonics for transmittance spectra are analyzed by use of Fast Fourier Tr...

Zinc Oxide (ZnO) has attracted interest due to its potential applications including nonlinear optical devices, blue‐violet emission device, buffer layer for GaN‐based devices, visible‐range transparent electrodes for solar cell and flat panel displays, surface acoustic wave devices, piezoelectric and piezo‐ optic devices, gas sensors for oxygen, and integrated opt...

Measurements of middle ear (ME) acoustic power flow (power reflectance, power absorption, and transmittance) and normalized impedance (acoustic resistance, acoustic reactance, and impedance magnitude) were compared for their utility in clinical applications. Transmittance, a measure of the acoustic power absorbed by the ME, was found to have several important advantages over other measures of a...

abstract background and aim: consider ing based on the presence or absence of swelling of the optic disc, optic neuritis classified nto two types of anterior and retrobulbar optic neuritis. the aim of this study was to compare the visual functions of patients with anterior optic neuritis and retrobulbar optic neuritis. materials and methods:this cross-sectional study was conducted in 48 patient...

We investigated the cause of optical transmittance degradation in tapered fibers. Degradation commences immediately after fabrication and it eventually reduces the transmittance to almost zero. It is a major problem that limits applications of tapered fibers. We systematically investigated the effect of the dust-particle density and the humidity on the degradation dynamics. The results clearly ...