Slit lamp ophthalmodynamometry was done by Dynoptor instrument in 6 cases of internal carotid artery, insufficiency, 18 cases of middle cerebral artery thrombosis and 20 control cases free from neurological disease. The average difference between the ophthalmic artery pressures of the two sides was 7.6% (diastolic) and 4.8% (systolic) in control cases. It was 6.6% (diastolic) and 4.6% (systolic) in cases of middle cerebral artery thrombosis. This difference was much higher in cases of<sup> -</sup>sub internal carotid artery insufficiency (41.3% ′diastolic and 25.4% in systolic); thus elucidating the role of ophthalmodynamometry as a non-invasive technique in diagnosis of these cases