Background: Tear film stability is the key event in ocular surface diseases. The purpose of this study is to evaluate
spatial and temporal progression of the tear film breakup using an automatic non-invasive device.
Methods: Non-invasive tear breakup time (NITBUT) parameters, such as First NITBUT (F-NITBUT) and Average
NITBUT (A-NITBUT), were evaluated in 132 glaucoma and 87 control eyes with the Keratograph 5 M device. Further
analysis of this data was used to determine size, location and progression of tear film breakup with automatically
identified breakup areas (BUA). The progression from First BUA (F-BUA) to total BUA (T-BUA) was expressed as Dry
Area Growth Rate (DAGR). Differences between both groups were analysed using Student t-test for parametric data
and Mann-Whitney U test for non-parametric data. Pearson’s correlation coefficient was used to assess the
relationship between parametric variables and Spearman in the case of non-parametric variables.
Results: F-NITBUT was 11.43 ± 7.83 s in the control group and 8.17 ± 5.73 in the glaucoma group (P = 0.010). A-NITBUT was
14.04 ± 7.21 and 11.82 ± 6.09 s in control and glaucoma groups, respectively (P = 0.028). F-BUA was higher in the glaucoma
group than in the control group (2.73 and 2.28; P = 0.022) and was more frequently located at the centre of the cornea in
the glaucoma group (P = 0.039). T-BUA was also higher in the glaucoma group than in the control group (13.24 and 9.76%;
P = 0.012) and the DAGR was steeper in the glaucoma group than in the control group (34.38° and 27.15°; P = 0.009).
Conclusions: Shorter NITBUT values and bigger, more central tear film breakup locations were observed in the glaucoma
group than in the control group. The DAGR indicates that tear film rupture is bigger and increases faster in glaucomatous
eyes than in normal eyes