Characterized by a progressive loss of ganglion cells and the retinal nerve fiber layer and related to a higher intraocular pressure (IOP) than normal, glaucoma can be divided into open-angle and angle-closure, which is more aggressive and known for reaching extremely high IOP levels.

At the time the technique idealized and known as a prone position provocative test for angle-closure glaucoma was created, optical coherence tomography (OCT) did not exist, so angle-closure glaucoma was determined by comparing IOP measurements before and after patients lie in the prone position. 

A team of researchers improved this technique by incorporating OCT to help identify the camerular sinus type and improve the diagnosis of angle-closure glaucoma by performing OCT of the anterior segment in the lying position.