Changes Caused by Fluorescein in the Tear Film Evaluated with Hybrid Break-up Time Test as a New Method - Part Two: Its Effect on Breakup Locations and other quantitative values.

OBJECTIVES: To examine the changes caused by fluorescein in the tear film by analyzing the qualitative parameters such as breakup location and also detailed quantitative parameters.

METHODS: After determining the break-up time (BUT) value and breakup locations by the Non-invasive break-up time (NI-BUT) method, we re-evaluated the changes in the tear film stained with fluorescein using the topographical method. We called the topographic evaluation of the tear film stained with fluorescein as the Hybrid-BUT test. The results for the parameters obtained for each participant by the NI-BUT and Hybrid-BUT tests were compared.

RESULTS: Our study was conducted with 82 participants aged between 18 and 58 years (mean age 34.1±11.1). The mean first break-up time value (BUT1 ) was 4.1±2.7 sec on the NI-BUT test versus 5.1±3.2 sec on the Hybrid-BUT test (p=0.029). The mean average of all break-up time values (BUTAvg ) for each participant was 7.2±3.2 sec on the NI-BUT test versus 8.4±3.1 sec on the Hybrid-BUT test (p=0.004). After dividing the corneal surface into quadrants of 90 degrees, there was no significant difference in the comparison of the locations of the first breakup (QUAD(First breakup) ), the second breakup (QUAD(2nd breakup) ) and the third breakup (QUAD(3rd breakup) ) between the two tests (p>0.05).

CONCLUSIONS: Fluorescein affects quantitative values rather than qualitative parameters in tear film. We observed that the change caused by fluorescein in tear film break-up time could be detected objectively and in a documented manner using Hybrid-BUT test.