Quantitative evaluation of the strabismus patient.

Quantitative techniques of measuring ocular motor function have proven extremely useful in evaluating the strabismus patient. The forced duction test has been valuable in determining the extent of mechanical restrictions and, in some instances, indirectly provides information about muscle strength. The active force generation test is a direct measure of active muscle force, while the differential intraocular pressure test (which may be easier to perform) provides data on active force indirectly. Saccadic velocity studies reveal the presence of muscle paresis or paralysis as contrasted with restrictions. Several neuro-ophthalmic conditions have typical eye movement patterns that are helpful in identifying them correctly. Saccadic velocity tests can also be helpful in diagnosing a disinserted extraocular muscle. Quantitative studies assist in more accurate diagnosis and are helpful in therapeutic decision making in terms of the timing and type of therapy indicated.