What term describes a small or constricted pupil?

The term that describes a small or constricted pupil is "miosis." This condition can occur in various situations, such as in response to certain medications, lighting conditions, or as a result of some underlying medical issues. Miosis is often a physiological response to bright light, helping to protect the retina from excessive illumination, or it can be a sign of specific neurological conditions or toxicity.

In the context of this question, the other terms refer to different conditions that are not related to pupil size. Myopia refers to nearsightedness, where the eye cannot focus on distant objects properly. Astigmatism is a refractive error caused by an irregular curvature of the eye's lens or cornea, leading to blurred vision at any distance. Hyperopia, or farsightedness, is the inability to see near objects clearly while distant objects may be seen more clearly. All these terms pertain to vision and refractive issues rather than the state of the pupil itself, which reinforces why miosis is the correct answer for describing a small or constricted pupil.