A new system, consisting of a double-channel Fabry-Perot etalon and laser diodes emitting around 780 nm, is described and proposed for use for measuring air-refractive index. The principle of this refractometer is based on frequency measurements between optical laser sources. It permits quasi-instantaneous measurement with a resolution of better than 10(-9) and uncertainty in the 10(-8) range. ...

PURPOSE To assess the normal values and the repeatability of the Galilei Dual Scheimpflug Analyzer (GDSA), the biometer IOL Master, and the autokerato/refractometer WAM 5500 in anterior segment examinations. METHODS Eighty-eight eyes from 88 healthy volunteers were prospectively and consecutively recruited. The repeatability was assessed, calculating the intraclass correlation coefficient (IC...

Optical techniques used for the measurement of the optical properties of blood are of great interest in clinical diagnostics. Blood analysis is a routine procedure used in medical diagnostics to confirm a patient's condition. Measuring the optical properties of blood is difficult due to the non-homogenous nature of the blood itself. In addition, there is a lot of variation in the refractive ind...

In this work, we are interested in the denaturation process of a laccase from Tramates versicolor via the determination of the refractive index, the refractive index increment and the specific volume in various media. The measurements were carried out using an Abbe refractometer. We have shown that the refractive index increment values obtained from the slope of the variation of the refractive ...

paratus. In activity 2, students can use the equipment used by hobby winemakers – a vinometer – to measure the alcohol content of the must and wine. 3. A well balanced wine needs a certain amount of fruit acid; the total acid content is a very important measure, because it directly affects the flavour. In activity 3, the acid content is determined by pH titration. Four further activitiesw2 can ...

PURPOSE To assess objective and subjective methods to measure accommodation in a young human population. SETTING Research laboratory, University of Houston, College of Optometry, Houston, Texas, USA. METHODS Accommodation was measured in the right eye of 15 young subjects (9 women and 6 men) whose ages ranged from 23 to 28 years and 1 36-year-old subject. The mean age of all subjects was 26...

PURPOSE The purpose of the present study was to develop mathematical relationships that allow obtaining equilibrium water content and refractive index of conventional and silicone hydrogel soft contact lenses from refractive index measures obtained with automated refractometry or equilibrium water content measures derived from manual refractometry, respectively. METHODS Twelve HEMA-based hydr...

We present a thiol-ene/methacrylate-based polymer capable of creating both physical fluidic features and optical index features via a series of three UV mask-lithography steps. The process of creating the two types of features are addressed independently by control of the polymerization and diffusion rates within the polymer system. The rapidly curing methacrylate creates a gelled, rubbery scaf...