Tear parameters DM Control (n=50) p-value1* p-value2**
No DMR (n=56) NPDR (n=40) PDR (n=30) All DM (n=126)
Schirmer (mm) Mean±SD 10.61±5.50 7.76±3.14 5.80±3.04 8.60±4.69 11.29±2.19 0.000 0.000
Range 3-35 3-16 2-15 2-35 8-16    
TBUT (s) Mean±SD 8.15±2.64 6.67±2.68 5.92±2.41 7.16±2.75 9.51±1.94 0.000 0.000
Range 3-12 3-14 2-10 2-14 3-12    
Staining (score) Mean±SD 0.72±0.76 0.93±0.78 1.76±0.93 1.10±0.89 0.31±0.56 0.000 0.000
Range 0-2 0-3 0-3 0-3 0-2    
TMH (μm) Mean±SD 260.89±66.94 227.38±71.39 184.96±90.42 233.42±78.57 309.13±44.63 0.000 0.000
Range 112-461 59-323 28-377 28-461 192-395    
TMD (μm) Mean±SD 166.56±48.93 143.71±50.23 116.96±50.10 148.27±52.70 185.16±41.93 0.000 0.000
Range 80-292 39-291 24-197 24-292 117-299    
TMA (mm2) Mean±SD 0.0320±0.017 0.0227±0.010 0.0171±0.010 0.0256±0.015 0.0358±0.011 0.000 0.000
Range 0.00-0.07 0.00-0.05 0.00-0.04 0.00-0.07 0.01-0.06    
* ANOVA test between groups
** Two-tailed t-test between DM and control group
DM: Diabetes Mellitus; DMR: Diabetic Retinopathy; NPDR: Non-Proliferative Diabetic Retinopathy; PDR: Proliferative Diabetic Retinopathy; SD: Standard Deviation;
TMH: Tear Meniscus Height; TMD: Tear Meniscus Depth; TMA: Tear Meniscus Area; TBUT: Tear-film Break-Up Time.
Table 2: Tear parameters in diabetes mellitus patients and normal subjects.