Method and device for optical measurement of biological properties

A method operable on a device comprising at least one light source configured and operable to illuminate an examined tissue with light radiation of one or more wavelengths with a direction of the at least one light source defined by the longitudinal and central axis thereof and a light detector configured to be located at a same side of said examined tissue, wherein the light detector is configured to receive light components of said one or more wavelengths reflected from the examined tissue in response to the illuminated light radiation for measuring biological properties of an examined tissue, the method comprising:

• measuring, by the device, the value of the ratio between light waves reflected from blood vessels of the examined tissue and the combination of light waves reflected from other parts of the examined tissue;
• configuring the angle between the at least one light source and the light detector to maximize the ratio value between light waves reflected from blood vessels of the examined tissue and the combination of light waves reflected from other parts of the examined tissue, wherein at least one light source direction is positioned at an angle of at least 2 degrees from the direction of light detector imaginary line perpendicular to the examined tissue or form an angle of at least 2 degrees between the light source direction and light detector direction;
• starting to operate the device in order to examine the examined tissue;
• wherein the direction of the at least one light source is oriented away from the direction of the light detector;
• wherein a distance between the at least one light source and the light detector is optimized relatively to the angle formed between the at least one light source direction and the direction of light detector imaginary line perpendicular to the examined tissue to collect an optimized signal from the blood vessel.