Glaucoma ducts, and narrowing or closure of the angle between the iris and cornea. The primary division in categorizing different types of glaucoma is open-angle and closed-angle (or angle-closure) glaucoma. In open angle glaucoma, the iris meets the cornea normally, allowing the fluid from inside the eye to drain, thus relieving the internal pressure. Where this angle is narrowed or closed, pressure increases over time, causing damage to the optic nerve, leading to blindness. Primary open-angle glaucoma (also, "primary glaucoma", "chronic glaucoma") refers to slow clogging of the drainage canals resulting in increased eye pressure which causes progressive optic nerve damage.
Supernumerary body part Supernumerary body part Supernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs. Many additional body parts form by the same process as conjoined twins: the zygote begins to split but fails to completely separate. This condition may also be a symptom of repeated occurrences of continuous inbreeding in a genetic line. Specific types of additional body parts include: Vestigial structures are anatomical structures of organisms in a species which are