Retention periods of diagnostic dyes on a cut corneal wound

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.