The most common surgery performed for glaucoma. Here, a flap is made in the scleral wall of the
eye (the white of the eye), and a window opening made under the flap to remove a portion of the
trabecular meshwork. The scleral flap is then sewen loosely back in place. This allows internal fluid
to flow out of the eye through this opening, resulting in lowered internal pressure and the formation
of a bleb or fluid bubble on the surface of the eye. Scarring can occur around or over the flap opening,
causing it to become less effective or lose effectiveness altogether.

Visual  Field Test

Visual field testing is most commonly used to detect any signs of glaucoma and damage to the
optic nerve. Also, visual field tests are useful for detection of central or peripheral retinal disease,
eyelid conditions such as drooping, optic nerve disease, and diseases affecting the visual pathways
to the brain. The visual pathways carry information from the eye to the visual cortex in the brain,
where this information is processed into vision.