convergence

n. the rotation of the two eyes inward toward a light source so that the image falls on corresponding points on the foveas. Convergence enables the slightly different images of an object seen by each eye to come together and form a single image. The muscular tension exerted is also a cue to the distance of the object from the eyes.

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Psychology term of the day

February 24th 2025

motor neuron disease

any one of a group of degenerative disorders of the lower motor neurons or both the lower and upper motor neurons, marked by progressive weakness and wasting of skeletal muscles and paralysis. This group of disorders includes several forms, but—especially in the United States—the term often is applied specifically to amyotrophic lateral sclerosis.