Improvement in Tear Ferning Patterns of Sheep Tears After Addition of Various Electrolyte Solutions

Effect of monovalent electrolyte solutions on the human tear ferning pattern

PURPOSE

To investigate the effect of the addition of a low concentration of sodium chloride (NaCl) and potassium chloride (KCl) solutions on the tear ferning (TF) patterns of tears collected from humans.

METHODS

A tear sample (20 μL) was collected from the right eye of 23 males and 7 females (25.4 ± 6.6 years). The tears were collected in one sitting for healthy subjects (N = 13). For dry eye participants (N = 17), the tear samples were collected in two separate settings with five minutes gap in between. A sample (1 μL) from each tear was dried on a glass slide, and the obtained ferns were observed using a microscope and graded using the five-point TF grading scale. Mixtures of tear samples (0.5 μL) and different volumes (0.5-2.5 μL) of each electrolyte (10-30 mg in 100 mL of water) solution were prepared, and their TF patterns were recorded and compared with those of the corresponding pure tears.

RESULTS

Significant improvements (Wilcoxon test, P < 0.001) have been seen in the TF grades of the tear samples after the addition of NaCl and KCl solutions. A significant difference (Wilcoxon test, P = 0.016) was found between the TF grades when NaCl and KCl solutions were added to the tear samples. The TF grades of pure tears collected from dry-eye subjects ranged from 2.1 to 3.5, based on the five points grading scale, and decreased to be in the range of 0.4 to 1.6 after the addition of electrolyte solutions. While the TF grades of pure tears collected from normal-eye ranged from 1.2 to 1.9 and improved after the addition of electrolyte solution to be in the range of 0.4 to 1.5.

CONCLUSIONS

The TF test was used in vitro to assess the impact of the addition of a low concentration of sodium and potassium chloride solutions on tears collected from humans. The TF grades of human tears significantly improved after the addition of either sodium or potassium chloride solution. The mechanism for the improvement in TF grades due to the addition of electrolyte solutions must be investigated.

The Effect of the Addition of Electrolyte Solutions on the Ferning Patterns of Tears Collected from Normal Eye Subjects

SIGNIFICANCE

The current study is the first report to describe the improvement of ferning patterns of human tears using electrolyte solutions. The results can help in the production of new artificial tears to improve the quality of tears.

PURPOSE

This study aimed to investigate the effect of the addition of different volumes of various electrolyte solutions on ferning patterns of human tears.

METHODS

Tear samples (20 μL) were collected from the right eye of 13 subjects (5 men and 5 women) aged 19 to 36 years (27.1 ± 5.1 years) with normal eyes. Then, 1 μL of each tear sample was dried on a microscopic glass slide, and obtained ferns were observed using light microscopy and graded using the 5-point tear ferning (TF) grading scale. Homogenous mixtures of each tear sample (0.5 μL) and different volumes (0.5 to 5 μL) of each electrolyte were prepared. A sample (1 μL) of each mixture was dried, and the ferns obtained were graded and compared with those of the corresponding tears collected from subjects before the addition of electrolyte solutions.

RESULTS

After the addition of electrolyte solutions, the TF grades of tears collected from healthy humans were generally improved. Significant (Wilcoxon test) improvements have been seen in the TF grades of the tear samples after the addition of a solution of potassium chloride (P = .03), calcium chloride (P = .01), magnesium chloride hexahydrate (P = .002), and sodium dihydrogen phosphate (P = .002). No significant improvements in the TF grades were seen after the addition of sodium chloride solution (P = .33).

CONCLUSIONS

Ferning grades of human tears improved with most of the electrolytes used.

Advances in Dry Eye Disease Examination Techniques

Dry eye-related ocular surface examination is very important in the diagnosis and treatment of dry eye disease. With the recent advances in science and technology, dry eye examination techniques have progressed rapidly, which has greatly improved dry eye diagnoses and treatment. However, clinically, confusion remains about which examination to choose, how to ensure the repeatability of the examination, and how to accurately interpret the examination results. In this review, we systematically evaluate previous examinations of dry eye, analyze the latest views and research hotspots, and provide a reference for the diagnosis and management of dry eye.