purpose: controversy has recently risen about the presence of compensatory ocular countertorsion (coct) after head tilt. this study was performed to define the functional range of this phenomenon. methods: cycloplegic autorefraction was performed on 80 eyes with regular astigmatism 2d. objective autorefraction was performed in normal position, right and left head tilt positions of 5º, 10º, 15º,...

Pulsatile ocular blood flow, intraocular pressure, systemic blood pressure, and heart rate was measured in two groups of 15 patients. One received lignocaine 1.5 mgtkg intravenously prior to induction. There was a significant increase in intraocular pressure after suxamethonium, which was not associated with any rise in ocular blood flow. Both the IOP and ocular blood flow increased significant...

A submersible analyzer (Geochemical Anomaly MOnitoring System, GAMOS-IV) powered by micro-diaphragm pumps has been developed for in situ monitoring of time-series changes in manganese concentrations. The analyzer determines dissolved manganese in a continuous manner using a H2O2-luminol chemiluminescence method. The analyzer operates with a sample and reagent flow rate of approximately 60 ml/mi...

Nonlinear systems can be probed by driving them with two or more pure tones while measuring the intermodulation products of the drive tones in the response. We describe a digital lockin analyzer which is designed explicitly for this purpose. The analyzer is implemented on a field-programmable gate array, providing speed in analysis, real-time feedback, and stability in operation. The use of the...

Concentrations of ampholytes in the nitrogen pool of ox ocular tissues and nervous tissues were analyzed systematically by an automatic amino acid analyzer with a special reference to their minor components. DCEC was found in lens and also in nervous tissues. Ophthalmic acid was found in lens (highest), in retina (moderate), and in vitreous humor and spinal cord (trace). Glutathione content was...

PURPOSE To determine the effect of caffeine on microcirculation in the human ocular fundus. METHODS The microcirculation in the ocular fundus of 10 healthy volunteers (10 eyes) was studied using a laser speckle tissue circulation analyzer. Caffeine or placebo (100 mg) was administered orally in a double-masked manner. Square blur rate (SBR), a quantitative index of blood flow velocity, was me...

Background: Dry eye disease (DED) is a common and debilitating condition that affects millions of people worldwide. Despite its prevalence, the diagnosis management DED can be challenging, as multifactorial symptoms nonspecific. In recent years, there have been significant advancements in diagnostic technology for DED, including development several new devices. Methods: A literature review arti...

PURPOSE To investigate the long-term effect of 0.12% isopropyl unoprostone (Rescula) on microcirculation in the human ocular fundus. METHODS A laser speckle tissue circulation analyzer was used to measure normalized blur (NB), a quantitative index of blood flow velocity, in the optic nerve head (ONH) and choroid-retina before and 4.5 hours after the instillation of a placebo into both eyes of...