Have you noticed any changes in your vision? Yes, in fact I’m starting to have trouble reading the street signs while driving. Well then, sit back in the chair and relax. I’m going to dim the lights and have you read the letters while looking through the machine–which letter is sharper? This one or this one? This one or this one? This one or this one…Sound familiar? For those of us who wear glasses, this is a routine visit to the optometrist.

Have you noticed any changes in your vision? Yes, in fact I’m starting to have trouble seeing the jumps–especially at dusk. I also have been bumping into the pasture fence more that usual. Well then, stand there and relax. I’m going to dim the lights and have you read the images while looking through the machine–which carrot is sharper? This one or this one? This one or this one? This one or this one? Unfortunately this conversation will never happen.

We have worked with a horse which has just completely freaked out over some really stupid thing on the ground or in the barn that has been there for years. What is it about today that caused the tire on the ground or brush on the ledge of a grooming stall to trigger the release of every inner demon of your horse’s mind, simultaneously? Could it be the beginning of a vision problem? Most likely not, but it never hurts to rule it out.

Theories and controversy regarding just exactly how a horse visually perceives its world have existed for more than a century. The main questions asked and remaining ones to be definitively answered are:

  1. Does the horse bring a visual image into focus using the "