Effect of forced eye opening on non-invasive tear film break-up time by Keratograph 5M in healthy individuals

AIM:To investigate the difference of non-invasive tear film break-up time(NIBUT)by Keratograph 5M before and after forced eye opening in healthy individuals. METHODS: Prospective case self-control study. Forty normal volunteers(79 eyes)were enrolled. Tear film images were captured, non-invasive first tear film break-up time(NIBUTf), non-invasive average tear film break-up time(NIBUTav)and dry eye level were measured by Keratograph 5M automatically before and after forced eye opening in each subject. For the first time, we checked the left eye after the right eye, and the second time checked the right eye after the left eye. RESULTS: The average of NIBUTf and NIBUTav were 9.18±5.52s, 11.74±5.59s respectively and percentage of every level of dry eye were 43%, 37%, 20% respectively before forced eye opening. The average of NIBUTf and NIBUTav were 8.91±5.54s, 11.76±5.58s and percentage of dry eye at different levels were 35%, 48%, 16% respectively after forced eye opening. There was no significant difference on NIBUT and dry eye level by Oculus keratograph 5M in normal subjects(t=0.37, P=0.72; t=-0.038, P=0.97; Z=-0.42, P=0.68). CONCLUSION: There is no influence on NIBUT and dry eye level by detected Keratograph 5M before and after forced eye opening in healthy subjects.