Abstract
Background. Good quality of tear film is essential for healthy vision in both animals and humans. Therefore, improving the quality of tears through the addition of electrolytes is important. Objectives. To assess the effect of adding various electrolyte solutions on tear ferning (TF) patterns collected from goats and camels. Materials and methods. Tear samples (20 mu L) were collected from 5 goats (2 males and 3 females; 3.4 +/- 1.6 years) and 5 camels (2 males and 3 females; 4.0 +/- 1.1 years) using microcapillary tubes. A tear sample (0.5 mu L) from each animal was mixed with various volumes (0.5-5 mu L) of each electrolyte solution to produce homogenous mixtures. A sample (1 mu L) of each mixture was dried on a microscopic glass at 22 degrees C with a humidity <= 40%. The obtained TF pattern was observed, graded and compared with those obtained for the corresponding pure tear samples. The effect of dilution using purified water on the TF patterns of animals was also tested. Results. The TF grades of animals were generally enhanced when mixed with electrolyte solutions. Specifically, the TF grade for tears collected from a goat was improved from 1.4 to 0.7 and to 0.8 when magnesium chloride hexahydrate and calcium chloride were added, respectively. Similarly, the TF grade for tears collected from a camel was improved from 1.8 to 0.9 and to 1.1, when calcium chloride and sodium dihydrogen phosphate solutions were added, respectively. Conclusions. The TF grades of tears collected from both goats and camels were improved after adding electrolyte solutions, and they were most remarkably improved when divalent electrolyte solutions were added, followed by the hydrogenated electrolyte.