Lacrimal plugs as a therapy for contact lens intolerance

We investigated whether canalicular occlusion with a lacrimal plug could increase objective and/or subjective comfort in contact lens (CL) wearers (n = 9) with both a history of lens intolerance and relative tear fluid deficiency. A modified Schirmer test (MST) was performed with the lids closed and under topical anaesthesia. Patients with values of < or = 10 mm/5 min were included. The plugs were inserted into the inferior canaliculus of the eye with the lower MST result; the contralateral eye served as a control. Conjunctival hyperaemia, Rose-Bengal and fluorescein scores, as well as subjective irritation, decreased significantly in plugged eyes at the 1 month follow-up visit but had returned to the pre-operative level at the 3 month visit. Tear fluid plasmin activity was elevated prior to plug insertion. Plasmin activity of the plugged eye was significantly lower at the 1 month visit but neither tear fluid flow (in the collection capillary) nor plasmin release showed any changes. The mean MST value improved significantly, whereas conjunctival chemosis and limbal hyperaemia showed no improvement at the 1 or 3 month follow-up visits after inferior punctual occlusion. Occlusion of the lower canaliculus with a lacrimal plug seems to induce a relatively short-lasting subjective and objective benefit for CL wearers. Plug escape or adaptive changes in lacrimal fluid secretion/elimination rate probably took place during the follow-up. The association of increased plasmin activity with tear deficiency might lead to enhanced tissue proteolysis, and thus contribute to CL-related ocular surface changes.