When an ophthalmologist suspects glaucoma, he or she usually performs a gonioscopy to closely examine the "angle", where fluid drains out of the eye. First, the pupils are medically dilated and the eye is numbed with topical drops. The ophthalmologist then uses a handheld goniolens to direct a beam of light at the angle, which is magnified through a specialized microscope called a slitlamp. The goal of the examination is to reveal problems with the angle that could hamper drainage and consequently endanger the optic nerve (due to the increased intraocular pressure). Once the mydriatic medication and the anaesthetic are in full effect, the procedure creates very little discomfort and generally takes only a few minutes, which is much less time than it takes for the dilation drops to wear off.