Abstract
Abstract: :
Purpose: The most frequent injury is mechanical but we describe the lesser known chemical interactions that occur due to the complex chemical composition of most fireworks and how they may be altered by changing the intercellular milieu to acidic or basic by impregnating cardboard and paper fillers with appropriate salts. The effect of pH changes on thermal injury to ocular structures will be described histologically. Methods: Appropriately anesthetized pigmented rabbits, rats and mice were used in which one eye served as control. Aliquots of sulfur, sodium, or gunpowder were injected at room temperature and at experimental temperatures into cornea, anterior chamber, vitreous and uvea at different ambient pH. Commercially obtained "sparklers" were brought at measured distances to the eye at different ambient pH. Corneal surace temperature was measured. At 2 hours, 24 hours, 1 week and 2 weeks eyes were examined with slit lamp examination, indirect ophthalmoscopy, gross exam, and sectioned after fixation in 10% formalin and formaldehyde, and processed for light and electron microscopy, examined histopathologically and graded by an ocular pathologist. Results: Rabbits had higher grades of inflammatory reactions to even modest stimuli and were not judged to be suitable models. Varying degrees and types of injury were noted to the ocular layers depending upon the specific chemical agent, temperature, and pH as well as chronic changes consistent with tissue trauma, high concentration, and osmolarity. Sulfur caused lens opacities, cataract, and focal chorioretinitis. Sodium, in addition to local tissue reactions, could be corrosive. Conclusions:The type of tissue injures are determined by the chemical composition and construction of the device and reflected in complex temperature–related effects, as well as to the more widely known effects of particle size and velocity. By modifying factors in the construction of such devices, injuries to various ocular structures may be modified and possibly minimized.
Keywords: trauma • pathobiology • pathology: experimental