Principal Body System: Control
Definition: Sense organ comprising eyeball, optic nerve, brain and accessory structures, i.e. eyelids (including third eyelid, nictitating membrane) and lacrimal apparatus
Function: Regulates body activities through nerve impulses via visual pathway
The equine eye is the largest of any land mammal, and a beautiful thing to behold. Clear and bright, the lids tight, and the inside of the lid pale pink and moist.
A horse's visual abilities are directly related to the horse's behaviour and the fact that the horse is a flight animal. They never wink, so if your horse has one eye partially or completely closed, it means something may be wrong.
In Traditional Chinese Medicine (TCM), the eyes are described as the window to the inner workings of the body, with the eyes thought to be connected to all of the internal organs. Each part of the eye is associated with a particular element and corresponding Yang organ - the iris is represented by the liver; the heart relates to the corners of the eyes; the upper and lower eyelids correspond to the spleen, the conjunctiva the lung, and the pupil the kidneys. For healthy eyes, immunity is key.
However, although all the organs have their own connection to the health of the eyes, TCM considers that the liver is the key organ connected to proper eye function. The liver opens into the eyes, and chronic eye problems can usually be traced to a deficiency of liver Yin or blood, for example. It is thought in TCM that it is common to resolve eye disorders successfully by treating the liver.
Eye injuries and infections are fairly common in horses, but if ignored they can worsen quickly. If the eye becomes badly infected, the structures of the eye can be eroded until the entire eye collapses.
A typical sign that something is wrong is profuse tear production (lacrimation). At first, the eye may just water more than normal, but if secondary bacterial infection develops, there will be pus in the discharge. Our Cookie is prone to weepy eyes in winter and at times of extreme pollens, and I know from experience that it's all too easy to be accustomed to seeing a slight discharge, particularly associated with flies in summer or miserable winter weather, but this also means that a more significant discharge might be ignored.
The most common cause of poor vision is exposure to cold and dampness, depriving the eyes of vital warmth and nourishment which results in poor circulation to the eyes. Dust and flies don't help either. A fly mask can help, and you can clean the area very gently with a simple saline solution 3-4 times a day - this can be made up with 1-tsp salt to a cup of lukewarm water - it should taste like tears.
The good news is that there is a useful selection of effective herbs for equine eye health, and with prompt management many eye problems can be brought under control within a few days.
NB. Carrots are also well known as a nutritious food that is great for the eyes. The high carotene content is believed to stimulate cell renewal, and it also provides the material for the body to make Vitamin A which is essential for proper vision, especially night vision.