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The developed measuring system is based on a VR viewer, that has been modified to include all the optical/elctronics parts required. The Van Herick procedure is performed using a line laser instead of the slit lamp usually used, in order to design a portable instrument. According to the theory, the laser line must impinges on the eye with a 60◦ angle respect to the optical axis of the patient. The laser is moved by a piezoelectric actuator and, simultaneously, a camera acquires the projection of the laser line on the eye. A Raspberry board is used to control all the components of the system.

The device performs several steps to complete the measurement. The first operation performed consists in finding the correct position of the limbus; this will represent the reference position to perform the measurement. The image of the eye is acquired, in order to roughly determine the position of the limbus. Afterward, the laser is turned on and it starts the eye scan. The images captured by the camera are analyzed to measure the position of the laser line. When this position is equal to limbus position, the board starts to save twenty images of the eye, that will be successively analyzed to perform the Van Herick measurement. From these images, the contours of the laser line on the cornea (anterior/posterior) and the contour of the laser line diffused on the iris are analyzed to estimate the information of interest. See the Video