Differential intraocular pressure in strabismus diagnosis.

An evaluation of the differential intraocular pressure test in the diagnosis of non-comitant strabismus is described and the results compared with findings in ten normal subjects. Increased intraocular pressure occurring when an eye cannot complete a full duction indicates both the existence of a restriction and the presence of underlying muscle force generation. The differential intraocular pressure test is easily performed, non-invasive, generally reliable, and can be performed on children who are unlikely to cooperate with other types of diagnostic procedures. Although false-negative results may occur, this test nevertheless provides useful additional information to that normally obtained in a motility examination. When combined with passive forced ductions, an accurate picture of both active and passive components of the strabismus may be determined.