A modified Schirmer test: the fine-thread method for measuring lacrimation.

Fine cotton thread is used instead of the filter paper of the Schirmer test. One end stained with fluorescein is inserted into the lateral upper conjunctival sac for 5-30 seconds. The length of the soaked portion is measured in millimeters and the two eyes are compared with each other. One test consists of several consecutive measurements. This new method has many advantages over the conventional Schirmer test: (1) It takes less time (5-30 seconds, compared to Schirmer's method which takes five minutes); (2) It is less injurious to the eye than the stiff and rather large absorbing paper; (3) A diagnosis of lacrimal deficiency must be based on several consecutive measurements and the comparison between two eyes in each measurement (the lacrimation normally is very irregular in the same person). It is difficult to measure consecutively with filter paper; (4) The fine thread itself acts as a potent mechanical trigeminal stimulator and as absorbing agent; (5) The thread maintains a stable position in the eye, while the filter paper which hangs on the lower lid sometimes shifts out of place; (6) The fluorescein dye disappearance and dilution tests can be performed simultaneously; (7) This method can be applied to children.