b. Macular degeneration (Berson, pp 41, 50–54.)
Macular changes include the formation of drusen, subretinal neovascularization, and degenerative changes (depigmentation and atrophy) of the retinal epithelium. Drusen are hyaline nodules or colloid bodies deposited in Bruch’s membrane. Amsler grid testing is a method of evaluating the function of the entire macula. The patient looks at a square grid pattern; if he or she sees irregularities in the grid in the form of wavy or fuzzy lines, this indicates a scotoma (due to macular involvement). Open-angle glaucoma is an insidious form of glaucoma whereby the chamber angle remains open. Acute angle-closure glaucoma (also called narrow-angle glaucoma) is an ocular emergency in which the trabeculum suddenly becomes completely occluded by iris tissue. Patients complain of severe eye pain, nausea, and the presence of halos or rainbows around light. The pupil may be fixed and dilated secondary to the abrupt rise in intraocular pressure.