Equine Glaucoma!

The horse below presented as a 20 year-old gelding with a 1 year history of recurring eye cloudiness that was also associated with excessive tearing and squinting. When examined, the horse kept his eye partially shut and there was a moderate tinge of "blue" to the entire surface of the eye. The cornea was stained with fluorescein stain (bright green fluid pooling below the eye ball) for the presence of a corneal ulcer and non was detected. 

Closer inspection of the eye revealed a darker blue band that stretched across the cornea. This band is also known as a corneal striae and is caused by persistently increased ocular pressure.  These findings are consistent with equine glaucoma and indicate a significantly elevated pressures within the eye. The blue tint to the cornea is caused by edema and is also be associated with the increased ocular pressures. As in humans, these horses experience significant discomfort evident by their tearing and constant squinting.  Definitive diagnosis requires measuring the ocular pressure via a tonometer that can be easily performed in a stall with mild sedation. The incidence of equine glaucoma is higher than most suspect and is usually not diagnosed until after significant time has passed. Treatment includes medications to lower the ocular pressure; however, this condition is typically chronic and progressive in horses and often results in the loss of the eye. As a rule, if you find your horse with his eye half way or completely shut, it is strongly recommended that a veterinarian examine the eye and provide immediate medial treatment.