Retention periods of diagnostic dyes on a cut corneal wound

Abstract

Comparative studies of four main ophthalmic dyes were carried out on their ability, after a single short-term exposure, to stain a corneal incised wound.12 year–old Wistar rats weighing 180-220 grams were selected for the study. 4 experimental groups of 3 rats each were formed from them. Corneal incision wounds were inflicted on all animals. A 10.0% lidocaine solution was used to anesthetize the cornea. Before applying the cut wound, the animals were injected into anesthesia with the drug "Sevoflurane". The depth of the wound was monitored visually using a microscope at a magnification of 4-6 times. Next, the corneal cut wound was stained with various dyes: animals of group 1 – fluorescein, group 2 – riboflavin, group 3 – bengal pink, group 4 – lissamine green. The exposure of all dyes, before eliminating the excess, was 1 minute.The degree of corneal staining was evaluated and photodocumented immediately after the elimination of excess dyes and further after 10 min., 20 min., 30 min., 60 min., 90 min., and 120 min. The cornea was visualized and photodocumented using a microscope "jingleszcn 315W" at magnification x 6.0.For long-term studies, it is advisable to use bengal pink, which visualizes a wound defect within 60 minutes after staining. Lissamine green should be used in cases where a contrast is needed between the dye and the cornea, and/or the underlying structures of the eye. Fluorescein and riboflavin diffuse rapidly enough into the surrounding tissues, and also stain the tear film, which can give a false positive result when diagnosing a wound defect of the cornea.