Angle Evaluation

Modesto / Stockton LASIK Eye Surgery Specialist – Dr. Ash
Visante OCT – Angle Evaluation

Gonio Angle Evaluation

The gonio angle is the point in the anterior sgement of the eye where the iris root is attached to the wall of the eye.

The anatomical scleral spur is clearly markedGonio Angle with the measuring tools in place at the Scleral Spur


The Visante has a standard angle measurement tool.  This tool may be used for any structure.  The base of the angle is placed on the desired object and the arms are then used as calipers to measure the angle.  In case of the gonio angle the base is placed upon the scleral spur and then the gonio angle is measured.

The Visante 2.0 also added a new feature of irido-corneal tool.  This tool is a far more advanced measurement of the angle and takes into account the measurements of the angle openning distance and the trabeculo-iris surface area.  Both these measurements are automatically done at 500 microns and 750 microns away from the scleral spur.


The green dot is placed at the scleral spur.  The Visante automatically calculates all the other measurements.  Of course, it goes without saying that the measurements can be adjusted manually as well.  The image on the right is busy, but worth studying.  The yellow dot is automatically placed at 500 microns away from the green and the white dot at 750 microns.  The angle opening distance (AOD) is the distance from the yellow or white dot vertically until the iris surface is reached.  The AOD 750 is marked in the purple line in the right side image.  The trabeculo-iris surface area (TISA) trapazoidal area outlined at the 500 and the 750 microns area.  The TISA 500 is filled with red dots to denote the area in the right side image.  The final numbers are automatically calculated and generated by the Visante.

This page is written on 11/7/09 – still under construction.