PurposeTo the correlation between plasma osmolarity (Posm) and tear osmolarity (Tosm) in patients (54 patients, 88 eyes) who underwent cataract surgery was evaluated.MethodsBefore cataract surgery, routine pre-operative biochemical tests were… Click to show full abstract
PurposeTo the correlation between plasma osmolarity (Posm) and tear osmolarity (Tosm) in patients (54 patients, 88 eyes) who underwent cataract surgery was evaluated.MethodsBefore cataract surgery, routine pre-operative biochemical tests were performed, and Posm was determined from blood samples. Also, Tosm was measured using the TearLab system, and objective signs including tear break-up time (BUT), fluorescein staining, lissamine green staining, and Schirmer’s test were evaluated. Dry eye (DE) was diagnosed according to the Japanese criteria for DE.ResultsOf the 88 eyes, 4 were diagnosed as definite DE, 70 as probable DE, and 14 as normal. Since the number of definite DE was small, the eyes were divided into two groups: normal group (n = 14) and DE group (n = 74), which included definite DE (n = 4) and probable DE (n = 70). There was no correlation between Posm and Tosm, though Posm (293.32 mOsm/L) was significantly higher than Tosm (288.48 mOsm/L; p < 0.001). There was no significant difference in Tosm between the normal group (288.29 mOsm/L) and the DE group (288.51 mOsm/L). No patients had a Tosm higher than 310 mOsm/L even in the DE group. Correlations between Posm/Tosm and each DE sign value were not found. Of 54 patients, 18 were diabetic. Posm was significantly higher in diabetic (295.78 mOsm/L) than in non-diabetic (292.36 mOsm/L; p = 0.014) patients, while there was no significant difference in Tosm between diabetic and non-diabetic patients.ConclusionsThe results suggest that Tosm is independent of Posm, and Tosm elevation in DE occurs by some local mechanisms.
               
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