Comparison Of Nitbut Andtbut Techniques For The Assessment Of The Tear Film Stability.

The purpose of this study is to compare the non-invasive tear break-up time (NITBUT) and the invasive tear break-up time (TBUT) and to determine if the NITBUT can be used instead of the TBUT to assess the tear film stability. There have been concerns regarding the validity of the results obtained by the conventional TBUT technique. Recently several non-invasive techniques have been proposed as an alternative. The NITBUT was measured using the tearscope without the instillation of flourescein. The TBUT was measured by the conventional technique using sodium flourescein and the aid of a slit lamp biomicroscope. These techniques were done on normal subjects and subjects with dry eye. The results from this study suggest that there appears to be some significant difference (PS 0.02302) between the tear film stability observed by NITBUT and TBUT methods for all subjects (with and without dry eye). This difference appears to be more prominent for the subjects diagnosed with dry eye (P:S0.03906). For the normal subjects, there appears to be no significant difference between the means of the NITBUT and TBUT values (P:S0.1454). However, it is not clear if the significant difference between the NITBUT and the TBUT is consistent or not for all subjects.