A device that used to determine degree of red or green color vision deficit. A dial on the anomaloscope is adjusted until the viewer (patient) believes that the green-red balance is appropriate compared with a standard yellow light whose intensity can also be varied. When a person with normal color vision views the “match” made by a patient with abnormal color vision, a deficit in either red or green color vision is readily apparent.
Short-sightedness, requiring a concave lens to focus the vision. Near-sightedness, an eye that is too powerful or too long. The image forms in front of the retina; a person with myopia thus sees badly in far vision but well in near vision. A Refractive Error in which the eye over-focuses light. Rays of light traveling from a distant object are brought to focus in front of the retina. Requires a minus (concave) lens to correct.
An eye drop or ointment which dilates the pupil.