Purpose: The purpose of this study was to investigate if there was a difference in the tear film’s osmolarity before and after drinking coffee. ' Method: All subjects in this study were asked to fill in a questionnaire to diagnose factors in their subjective symptoms, the questionnaire TERTC-DEQ. The subjects with a total graduated points of over 17 were not allowed to participate in the further measurements. In the study there was a total amount of 38 subjects, were 5 participated twice for both measurements, coffee and water. The measurements were done by TearLab to bring the the osmolarity values, of coffee and water, the before and after measurements, to be compared with each column. Each subject was measured before the drinks was served, 200 milliliters of water or 200 milliliters of coffee. 45 minutes after the first measurement, after the intake of one of the liquids, then the second measurement was occured with TearLab.  All of these values and measurements was later compared to each columns of coffee or water. Results: There was no significant difference between neither the coffee or water results (p>0,05). Though there was a little quotable difference between the before and after measurement values of coffee, but not significant. Conclusion: There was no significant difference related to coffe drinking and tear osmolarity. There is no contribution to the tear film’s osmolarity and it will not work as a factor into the dry eyes diagnosis.

Syfte: Syftet med studien var att utvärdera om det fanns någon variation av tårfilmens osmolariet, morgon och kväll hos personer utan symptom av torra ögon. Metod: Tårfilmens osmolaritet mättes på totalt 30 patienter, två gånger på en dag; morgon och kväll. Mätningarna utfördes med TearLabTM osmolarity system. Både höger och vänster öga mättes på varje patient. Samtliga deltagande ombads fylla i en symptomenkät vid namn TERTC-DEQ. Endast personer utan symptom på torra ögon tilläts delta i studien. Alltså personer med totalt  17 poäng på TERTC-DEQ. Resultat: Ingen statistisk signifikant skillnad kunde iakttas hos personernas osmolaritet mellan morgon och kväll (P > 0.05). Slutsats: I studien kunde ingen skillnad på osmolaritet i tårfilmen iakttas mellan morgon och kväll hos personer utan symptom på torra ögon. Därmed tros tårfunktionen hos dessa personer fungera korrekt. Tårfilmens osmolaritet upprätthåller rätt balans och förändras därför inte från morgon till kväll. / Aim: The aim of this study was to determine if there is an diurnal variation in tear osmolarity among healty non dry-eye subjects. Method: The osmolarity of the tearfilm was measured in a total of 30 subjects twice a day; morning and evening, using the TearLabTM osmolarity system. Measurements were performed on both right and left eye in all the subjects. All subjects were asked to fill in a symptom questionnaire named TERTC-DEQ and only those with a total score of  17 points were allowed to participate in the study. Subjects below this score had therefore no symptoms of dry eye. Results: There was no statistical significant difference between the subjects tear osmolarity comparing the morning and evening values (P>0,05). Conclusion: This study did not show any difference in the subjects tear osmolarity, comparing morning and evening measurements. None of the individuals had any symptoms of dry eye. Therefore it is believed that in subjects with no symptoms of dry eye, the tear osmolarity remains stable between morning and evening.