P Baumbach | PubMed Health

PubMed1989

Absolute ocular fundus dimensions measured by multiple-beam interference fringes.

Multiple-beam interference fringes have been projected onto the retina to serve as a size reference for fundus photography. The absolute fringe spacing is determined by measurable parameters. The interference fringes are extremely narrow so that fringe maxima and fundus structures can be perceived equally well, and a high precision of measurement is achieved. The method has been applied to a model eye of varying ametropia (within +/- 7 diopters). The reproducibility of measurement is within 0.5%. In vivo measurements on human eyes demonstrate the clinical applicability.

Fundus Oculi↗

PubMed1985

A combined tc-PO2 and skin blood flow sensor.

A new approach to the determination of energy delivered to the skin during transcutaneous oxygen tension (tc-PO2) measurements was tested. The test was carried out using a tc-PO2 electrode constructed with an active thermal shield in order to provide more sensitive and specific heat transport measurements, and consequently to create the possibility of determining skin blood flow rates. The oxygen measurement properties did not differ from the conventional tc-PO2 electrode. In vivo measurements were performed on 11 adult volunteers. Skin blood flow was determined by a blood flow cessation technique to be 0.124 +/- 0.053 ml . cm-2 . min-1 at the start of the experiments, rising to 0.164 +/- 0.61 ml . cm-2 . min-1. Tc-PO2 changed from 56.2 +/- 9.8 mmHg (7.5 +/- 1.3 kPa) to 68.3 +/- 9.0 mmHg(9.1 +/- 1.2 kPa). It is concluded that a thermally shielded electrode makes it possible to determine the convectional component of the heat loss from the electrode to the skin and consequently to compute a relative measure of skin blood flow rate. The observed change in computed skin blood flow rate was correlated to the observed change in tc-PO2 (P less than 0.1).

Body Temperature Regulation↗