Ocular lesions following suspected lightning injury in a horse

To describe the gross and histopathological ocular findings in a horse following suspected lightning injury.

The eyes of a 2-year-old thoroughbred gelding were clinically and histopathologically evaluated following a severe lightning storm following euthanasia because of visual impairment.

Severe corneal edema and hydrops were noted clinically oculus dexter. Indirect ophthalmoscopy revealed bilateral symmetrical raised hyporeflective peripapillary geographic lesions. Histopathologic evaluation revealed corneal edema in the right eye with normal corneal endothelium. Posterior segment evaluation revealed localized, pericentral choroidal lesions characterized by the presence of hemorrhage, early fibrosis, and minimal lymphoplasmacytic, neutrophilic, and histiocytic inflammation with spindle cell proliferation. The retinas overlying the choroidal lesions were necrotic and mostly absent. Peripheral to the focal lesion, the retina abruptly returned to normal architecture peripheral to a zone of apoptotic photoreceptors. Centrally, swollen axons extended into the optic disc.

There have been few descriptions of ocular lesions in animals following suspected lightning injury. We believe these findings to be unique because of the type of thermal injury that may be characteristic of lightening injury. We do not know whether these lesions would have progressed over time.