Book of the Ten Treatises of the Eye the sclera, a thick, hard membrane which protects the inner parts of the nerves from injury. The chorioid, a thin and soft structure filled with veins and arteries, follows next and provides nourishment to the overall structure. Finally, the retina transmits nutrients to the lenses themselves. Hunayn then presents the system responsible for protecting the eye. From the outermost level, these are the conjunctiva, cornea, and uvea. While both the conjuctiva and cornea provide protection with minimizing hindrance to the lenses, the uvea has an extra function of concentrating the pneuma exiting out of the eye to prevent it from
Iris cyst a shadow with a tumor but almost never with a cyst. Ultrasound B-scan (USB) uses wavelengths of 10-20MHz to form an image of the eye. USB can be used to identify the extension of the iris cyst in either the anterior or posterior chamber. It can also be used to identify midzonal cysts behind the iris and to determine whether there is ciliary body involvement. The preferred method to determine ciliary body involvement however, is not USB but ultrasound biomicroscopy. Ultrasound biomicroscopy, (UBM) has a higher resolution than USB an di t also using soundwaves with a higher frequency from