Final answer:
Primary angle closure glaucoma can cause permanent damage to the optic nerve due to increased intraocular pressure. A force calculation using a specific eye area and net pressure illustrates the potential damage the optic nerve can endure. The optic nerve's role in vision is crucial as it transmits information to the brain, and its impairment can lead to vision loss.
Step-by-step explanation:
Primary angle closure glaucoma can cause permanent damage to the optic nerve. This condition occurs when there is a sudden increase in intraocular pressure due to a blockage of the drainage canals within the eye, leading to damage of the nerve fibers. To understand the extent of the force that can be exerted on the optic nerve consider the calculation using a net pressure of 85.0 mm Hg on the back of the eye's area of 6.0 cm² which yields a force of about 6.8 Newtons. The optic nerve is responsible for transmitting visual information from the retina to the brain, and its damage can result in vision loss.
In a situation where light exposure in one eye leads to pupil constriction in the other, it indicates a consensual reflex due to an intact oculomotor nerve connection on the reacting side. If this reflex fails to occur, it implies damage to the oculomotor nerve or related pathways though specifically in the context of glaucoma it is the optic nerve that is affected.