Influence of artificial tear solution on the electroretinogram of adult rats

Objective To observe the effect of artificial tear solution on the electroretinogram (ERG) of SD rats.Methods Fifteen adult SD rats were divided into 3 groups in this experimental study.After 6 hours of dark adaptation,a silver loop electrode was placed in contact with the cornea as the recording electrode. Stainless steel needles were used as reference and ground electrode.Different amounts of artificial tear (1％ carboxymethylcellulose sodium) were instilled in the recording eye: group one: the cornea was kept dry without artificial tear; group two: the amount of artificial tear was moderate; group three: the amount was excessive. ERG was recorded and the a- and b-waves were monitored.Data were analyzed with a one-way ANOVA and differeces between each group were compared by the LSD t test.Results In groups two and three, the interference was subtle and the baseline was smooth compared to group one. There was a statistically significant decrease in the a- and b-wave amplitudes in group three (t=4.112, P＜0.01; t=3.018,P＜0.05).Conclusion Artificial tear solution can reduce interference in ERG recordings but excessive amounts may affect the amplitude of the waves. Key words: Artificial tear;  Electroretinography;  SD rat;  Amplitude