Czech and Slovak Ophthalmology 430 Original article Tear Osmolarity in Patients with Lagophthalmos Píšová Alena Chovanec Martin Betka Jan Ferrová Květoslava Česká Burdová Marie Odehnal Milan Dotřelová Dagmar Mahelková Gabriela https://orcid.org/0000-0002-2244-3617 30 11 2016 5 2

Introduction: Lagophthalmos can be characterized as the dysfunction of the eye aperture and in some cases even by the disruption of tear production. Dry eye syndrome can consequently develop. Instability of the tear film, hyperosmolarity and inflammatory reaction are considered as the key mechanisms of dry eye syndrome. In our report we monitored the tear osmolarity of patients with postsurgical unilateral lagophthalmos. Results were compared with tear osmolarity of the non-lagophthalmic eyes. Methods: We examined 10 patients (6 women, 4 men) with postsurgical facial nerve palsy and lagophthalmos complicating management of either cerebellopontine (8 patients) or salivary gland tumors (2 patients). Only patients without severe corneal defects enrolled the study. The tear osmolarity was measured in lower tear meniscus by TearLab Osmolarity System device. The lagophthalmic eye was always examined first. The results are presented as mean plus/minus the standard deviation. The paired t-test was used for statistical data processing. The p-value ≤ 0,05 was considered as statistically significant. Results: The mean tear osmolarity of the lagophthalmic eyes was 296 ± 15,0 mosmol/l (275–315 mosmol/l). In case of healthy eyes the mean osmolarity was 310 ± 12 mosmol/l (292–336 mosmol/l). The tear osmolarity in case of lagophthalmos was significantly lower than in the healthy eyes (p = 0,05). Conclusion: In contrary to the studies demonstrating higher tear osmolarity under the scenario of dry eye syndrome, we found lower tear osmolarity in the lagophthalmic eyes than in the healthy eyes. The possible reason could be the changes in tear dynamics of the lagophthalmic eye due to disturbance of eye lid function. Our results also stress the need of evaluation of the actual tear osmolarity in the view of complex clinical eye findings. The place of tear collection should also be considered.

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