Eye disease in horses – when is referral needed?

such as the eyelid tend to need additional sometimes multimodal therapy with chemotherapeutics or specialised treatment such as radiotherapy strontium plesiotherapy or electrochemotherapy. Very few treatment centres offer such specialised therapies and as such your horse may need to be referred for evaluation and treatment. 
If you look closely at your horses eye you may notice small irregular protrusions from the edge of the pupil. These are called the corpora nigra. They can develop into cystlike structures known as corpora nigra cysts. These are benign and usually asymptomatic. However occasionally they can grow so large that they might be associated with unusual behaviour visual disturbances headshaking or refusal to jump. In these cases your vet may suggest referral for evaluation and treatment usually with transcorneal laser or aspiration of the cyst to reduce it in size. 
Recurrent uveitis
What is recurrent uveitis? This is a chronic debilitating inflammatory condition of the eye. Also known as ERU or Moon blindness as it was incorrectly thought to coincide with phases of the moon. Up to 19 of horses worldwide are thought to be affected. Horses tend to suffer from repeated episodes of painful inflammation in the eye followed by periods where the eye is comfortable and quiescent. Over time the horse may eventually become blind. In the first instance early cases of uveitis tend to be managed at home with the use of topical antiinflammatories or steroids and a drug to dilate the pupil. 
Many cases will respond well to this treatment for first or subsequent episodes. However some cases become exceedingly difficult to manage and some horses may have suffered from multiple lowgrade episodes before they are first noted. Repeated episodes will cause considerable discomfort to the horse not to mention the anxiety and financial burden felt by the owner. Your vet may choose to refer a case like this for evaluation and treatment by a specialist. Some of these cases may be suitable for specialist treatment. Treatment includes options such as surgery to remove inflammatory cells or the implantation of an implant or cyclosporine to control this inflammation. In some cases the disease may have progressed to the point where enucleation is necessary. 
Prepurchase examination
It is common practice for veterinary surgeons to carry out a detailed examination or vetting of horses prior to sale. As part of this process a detailed examination of the eye will be performed. In many cases