Non-invasive assessment of tear film stability with a novel corneal topographer in Indian subjects

The aim of the study is to investigate the applicability of a newly developed corneal topographer in assessing tear film stability in Indian subjects. A prospective comparative study of 25 Indian subjects with dry eyes attending a tertiary eye care clinic in South India and 25 normal control subjects was conducted. The diagnosis of dry eye was made based on ocular surface disease index questionnaire. Non-invasive tear film break-up time (NI-TBUT) was measured using a new method based on a corneal topographer equipped with modified scan software. The correlations between the NI-TBUT and the traditional fluorescein tear film break-up time (F-TBUT), Schirmer I test values were determined. A total of 50 patients (100 eyes) were included. The values of NI-TBUT were significantly lower than the values of F-TBUT in both the cases (NI-TBUT 5.78 ± 0.8 s and F-TBUT 7.56 ± 0.5 s; p < 0.02) and controls (NI-TBUT 11.66 ± 1 s and F-TBUT 12.92 ± 1.2 s; p < 0.01). NI-TBUT values were significantly lower than the corresponding F-TBUT values in the varying grades of dry eyes. The mean NI-TBUT values in mild dry eyes was 6.42 ± 0.2 s, moderate dry eyes was 4.70 ± 0.3 s and in severe dry eyes was 2.32 ± 1.2 s. There was a significant difference in the NI-TBUT values for cases and controls (p < 0.001). There was a good correlation seen between the NI-TBUT values and the F-TBUT values, Schirmer I values and the ODSI scores. NI-TBUT was found to have a sensitivity of 86.1 % and a specificity of 81.1 % when the cut-off value was kept at 6.2 s. We investigated the performance of a non-invasive technique for measuring tear film stability to aid in the diagnosis of dry eye disease. It is a useful non-invasive objective method for the detection of dry eye, and its varying grades and may be useful in monitoring the efficacy of therapies for dry eye.