Store eye medications in a clean, temperature controlled environment. Your house or a heated tack room are best. Most eye ointments come in metal tubes which can become brittle in cold weather. Also, cold eye ointment can be very stiff and difficult to get out of the tube and into your horse’s eye. Keep the tube in your pocket for a few minutes before giving the medication to make sure that the ointment is soft. In extremely hot summer weather it may be necessary to keep the ointment in a cool place. The ointment can become liquid when too hot.