Ocular surface analysis and automatic non-invasive assessment of tear film breakup location, extension and progression in patients with glaucoma

This is the authors' abstract. We don't add key points for this paper.

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 break-up using an automatic non-invasive device. Methods Non-invasive tear break-up 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 5M device. Further analysis of this data was used to determine size, location and progression of tear film break-up with automatically identified break-up 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 seconds 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 seconds 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 (34.38º and 27.15º; P=0.009). Conclusions Shorter NITBUT values and bigger, more central tear film break-up 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.