Knapp procedure
A surgical technique used to treat double elevator palsy by full tendon width transposition of the medial and lateral rectus muscles to the insertion of the superior rectus muscle. This allows the horizontal rectus muscles to act as elevators, improving elevation and reducing hypotropia.
Knapp’s law
A correcting spectacle lens placed at the anterior focal plane of an axially ametropic eye will form a retinal image equal in size to that formed in a standard emmetropic eye. Knapp’s law allows calculation of retinal image size and is useful for predicting aniseikonia, the image size difference between the two eyes.
Krimsky test
A method for objectively measuring the angle of strabismus. The clinician positions their eye directly above a light source that the patient fixates on. Prisms are placed in front of the fixating eye until the corneal light reflex appears centered in the deviated eye.