This horse had painful blind eye a week ago associated with nasal discharge. It seems to be recovering vision somewhat and now has developed these lesions around its optic disc. What is the condition and what is the prognosis?
This is probably an equine herpesviral retinitis with the development of what have been known as peripapillary ‘butterfly’ lesions. The signs are less severe in the other eye with only some of these small hyper-reflective ‘doughnuts’ in the retina. The prognosis for return of vision is reasonable especially as the inflammatory aspects of the lesion seems have regressed by now. Quite a few horses are seen with these changes as chronic post-inflammatory lesions and with no discernable visual defects.