Glaucoma progresses with stealth and late presentation is not unusual.This study explored the relationship between tear and serum ions concentration and glaucoma.The concentration of sodium,potassium and chloride in tear and serum of 50 glaucoma patients and 50 age and sex-matched controls were measured.Test and control groups had a mean age of 55.98±11.91 and 52.24±13.17 years respectively.The difference in their age was not statistically significant.Mean sodium,potassium and chloride concentrations(mmol/L)in tear of test subjects were 133.74±4.30,17.13±1.74 and 125.54±5.56 respectively while for control subjects,the values were 131.06±6.39,21.40±1.57 and 122.86±7.12 respectively.A paired comparison of mean between the 2 groups was statistically significant for potassium and sodium.A higher chloride ion concentration in test subjects was not statistically significant.The mean concentrations of sodium,potassium and chloride ions in the serum test subjects were 135.42±3.84,4.07±0.66 and 101.00±2.82 respectively while the mean concentrations in control subjects were 135.56±3.84,4.14±0.69 and 101.58±3.25 respectively.The comparison of means was not statistically significant.Sex did not significantly influence any of the measured variables but increasing age was related to decreasing potassium ion concentration in tear of glaucoma subjects in a statistically significant manner.Using a tear potassium concentration of 20 mmol/L as the lower limit of normal,the calculated sensitivity and specificity for making a diagnosis of glaucoma was 94%and 88%respectively.Low potassium ion concentration in tear of glaucoma subjects could be a useful biomarker in the disease but further research is needed.An effective glaucoma screening test can hold at-risk individuals from a greater distance of irreversible glaucoma blindness.