Structure and microanalysis of tear film ferning of camel tears, human tears and refresh plus

Purpose We investigated the tear ferning pattern and microelements of the tear film of camel and compare them with human tears and fresh plus eye lubricant. Methods The tear film pattern was investigated by light and scanning electron microscope. A small drop (1μl) of tears was placed on a glass slide at 23 degrees temperature and humidity of less than 45%. When the tears were dried, they were observed under the light microscope, Olympus BX1. The dried drop was also used to take images from an environmental scanning electron microscope. The microanalysis of the elements was done by using the STEM, JEOL 1400 transmission electron microscope. The Masmali grading scale for tear ferning was used to grade the ferning patterns. Results Light microscopy observations showed that the tear film pattern was surround by a thick peripheral homogenous layers which contained small oily droplets. The peripheral and central ferning contained very thin branches. The tear ferning at the periphery was between grades 1 to 2 whereas tear ferning pattern of the centre was between grades 0 to 1. The tear ferning pattern of human tears and fresh plus were between grades 1 to 2. The scanning electron microscope showed very tiny crystals in between the tear ferning. Edax analysis showed that mass percentage of chloride as highest in the camel tears and mass percentage of potassium was more than in the human tears but less than in the ‘Reresh plus’ lubricant. Conclusion Our observations suggest that camel tears are better quality than human tears and ‘Refresh Plus’ lubricant. This suggests that camels may have some extra tear compositions in their eyes, which help the animal to avoid the dryness in their eyes in the dry and harsh climatic conditions.