The Effects of Phosphate Buffered Saline on Corneal Chemical Alkali Burns

Background: Treatments administered after a corneal burn injury can have long term implications on wound healing. Initial treatments can include the administration of lubricants, anti inflammatories, and antibiotic eye drops, many of which contain phosphate buffered saline (PBS) as a vehicle. As a result, the purpose of this study was to observe the effects of the commonly used PBS ophthalmic drop vehicle on corneal alkali burns over 30 days when treated 4X daily for the first 14 days. Materials and Methods: Corneal alkali burns 5.5 mm in diameter were created on 10 anesthetized, male New Zealand White rabbits Animals (5) with corneal wounds were treated with PBS 4X daily or left untreated (5). Control animals (5) were not wounded, but were treated with PBS drops 4X daily. Corneal alkali burns were created by centrally placing NaOH (1N) soaked filter paper onto the cornea for 30 seconds. After removal of the filter paper, the surface of the eye was immediately debrided with a Weck-Cel® sponge and irrigated with 15 ml of sterile buffered salt solution (BSS). At days 0, 3, 7, 14 and 30 post-chemical alkali burn creation, eyes were evaluated by white light imaging and fluorescein staining. On days 14 and 30, corneal thickness was assessed via optical coherence tomography (OCT). Results: A significant decrease in fluorescein staining indicating a significant increase in wound healing was observed on day 7 (P< 0.05) in the PBS treatment group when compared to the non-treated corneal alkali burns. A significant increase in fluorescein staining or decrease in wound healing was observed on day 30 (P< 0.0005) in the PBS treatment group when compared to non-treated corneal alkali burns. White light imaging and OCT results, respectively, showed no significant differences in corneal opacity or corneal swelling between treatment groups at any time point. Conclusions: This study suggests that the treatment of corneal alkali burns with ophthalmic solutions containing PBS may impact wound closure while having no significant effect on corneal opacity or corneal swelling.