Treatment of Ocular Alkali Burns Using Extended Rinsing
Lee, Won Young; Ousterout, David; Shin, Mi Ran; Yu, Changhao
Many people work every day around potentially hazardous chemicals that can cause severe burns if the worker is exposed to the substance. Ocular alkali exposure is particularly dangerous and without immediate and proper treatment permanent vision loss will occur. The purpose of this project is to assess the pH levels in the eye, after alkali exposure and during subsequent treatments, by accurately modeling the cornea of the eye. We have found using our model that a typical exposure of 1M NaOH for 20 seconds leads to a pH of 14.1 and 12.7 at corneal surface and stroma/aqueous humor interface. After 15 minutes of rinsing with water, our model predicts pH values of 8.2, 11.8, and 12.0 in the corneal surface, stroma/aqueous humor interface, and aqueous humor, respectively. We have also found that it is vitally important to rinse as quickly as possible after exposure, as our model predicts significantly higher pH values and alkali penetration in the eye after only a few seconds of exposure. We have critically evaluated the sensitivity of this model to input parameters and found that it is relatively sensitive to mass transfer coefficient changes, which drastically reduce the minimum pH at the corneal surface. We also have evaluated our model against published literature to demonstrate its ability to model other given situations, specifically using ionic rinsing solutions instead of water. We believe that this model is accurate for modeling the stroma layer, while there is more work to be done in modeling the aqueous humor, which may have an unknown reaction rate for alkali removal. To obtain a better model of this process, we need to learn more about the physiology of the eye. We conclude that it is critically important that an individual try to use external protective equipment, proper training, and proper technique to prevent any exposure and that in the event of an exposure, rinsing begins immediately so that the chemical does not diffuse as far into the eye thus preventing further damage.
Eye; Alkali burn; Aqueous Humor