Objective To investigate the influence of thin-wall bleb on tear composition of glaucoma patients. Design Cross sec- tional observation. Participants 10 patients with thin-wall blebs, I 1 patients with thick-wall blebs, which were enrolled more than 6 months after filtering surgery, and 15 patients without filtering blebs were involved. Methods The concentration of ascorbic acid in tear was determined by ultraviolet spectrophotometer. Main Outcome Measures The concentration of ascorbic acid in tear. Results The concentration of aseorbic acid was （713.53±132.32）μg/ml in thin-wall bleb group, （502.52±93.90）μg/ml in thick-wall bleb group, and （470.95±86.85）μg/ml in without filtering blebs group, respectively. There was significant difference among the three groups （F=18.117,P=0.000）. The concentration of ascorbic acid in thin-wall bleb group was significantly higher than that in thick-wall bleb group and without filtering blebs group （P=0.000, P=0.000）. There was not significant difference between thick-wall bleb group and without filtering blebs group （P=0.446）. Conclusion Aqueous humor can exude from the wall of thin-wall blebs to the eye surface under the pressure imposed by eyelid and as a result the composition of tear is changed.
Ophthalmology in China