Having observed a very tight adhesion between the trochlea and the tendon of the obliquus superior bulbi muscle or an increase in tendon thickness posterior to the trochlea in operated patients, the author tried to correct this abnormality using partial trochleotomy and the lysis of the adhesions, followed by the application of Scott-Knapp sutures. The morphological basis of Brown's syndrome, consisting of an obstruction at the level of the trochlea, was demonstrated experimentally by means of an eye motion simulator.