Abstract
Purpose:
Serum and plasma are being used for the treatment of several eye diseases including keratomalacia and Keratoconjunctivitis sicca. The goals of this study was to analyze the electrolyte content found in equine and canine tears and compare it to the electrolytes found in serum and plasma obtained by utilizing two different anticoagulants.
Methods:
Nine horses (17 eyes) and 9 dogs (18 eyes) were used in this study. An eye examination including slit lamp biomicroscopy, fundoscopy, and Schirmer tear test (STT) was performed. All eyes were free of ocular disease. All horses were sedated with 0.5 mg/kg of xylazine (Lloyd Laboratories, Shenandoah, IA) intravenously. No chemical restraint was needed for the dogs. Tears and blood were collected from all animals. Blood was collected for serum in tubes with no anticoagulants; plasma was made by using two different anticoagulants: Citrate Phosphate Dextrose (CPD) and heparin.
Results:
Most of the electrolyte values in tears were statistically different than electrolyte values in serum and plasma in both dogs and horses. In both species, potassium and chloride levels were significantly (P<0.01) higher, and calcium levels were significantly (p<0.01) lower in tears compared to serum and plasma. In equine tears, a significantly (P<0.001) higher level of phosphorous was found in plasma made by use of CPD compared to tears, serum and heparinized plasma. However, in dogs, phosphorous levels were significantly lower (P<0.01) in tears in comparison to that found in serum and plasma regardless of the anticoagulant used.
Conclusions:
We found statistical differences between most electrolytes in tears compared to serum and plasma in dogs and horses. Further studies are needed to evaluate the importance of our results and the potential difference of the therapeutic effect of topically applied serum and plasma on precorneal tear film and corneal diseases.
Keywords: 486 cornea: tears/tear film/dry eye