Quote 4the day: Horses are our children, best friends and soul mates. Never let them go...
Fact 4the day: The anatomy of the equine eye
The equine eye includes the eyeball and the surrounding muscles and structures around the eyeball, termed the adnexa.
The eyeball of the horse is not perfectly spherical, but rather is flattened anterior to posterior. However, research has found that the horse does not have a ramped retina, as was once thought.
The wall of the eye is made up of th...ree layers: the internal or nervous tunic, the vascular tunic, and the fibrous tunic.
*The nervous tunic (or retina) is made up of cells which are extensions of the brain, coming off the optic nerve. These receptors are light-sensitive, and include cones, which are less light-sensitive, but allow the eye to see color and provide visual acuity, and rod cells, which are more light sensitive, providing night vision but only seeing light and dark differences. Since only 2/3 of the eye can receive light, the receptor cells do not need to cover the entire interior of the eye, and line only the area from pupil to the optic disk. The part of the retina covered by light-sensitive cells is therefore termed the pars-optica retinae, and the blind part of the eye is termed the pars-ceaca retinae. The optic disk of the eye, however, does not contain any of these light-sensitive cells, as it is where the optic nerve leaves to the brain. It is therefore a blind spot within the eye.
*The vascular tunic (or uvea) is made up of the choroid, the ciliary body, and the iris. The choroid has a great deal of pigment, and is almost entirely made of blood vessels. It forms the tapetum lucidum when it crosses over the fundus of the eye, causing the yellowish-green eye shine when light is directed into the animal's eyes at night. The tapetum lucidum reflects light back onto the retina, allowing for greater absorption in dark conditions. The iris lies between the cornes and the lens, and not only gives the eye its color, (see "eye color," below) but also allows for varying amounts of light to pass through its center hole, the pupil.
*The fibrous tunic consists of the sclera and cornea and protects the eye. The sclera (white of the eye) is made up of elastin and collagen. The cornea (clear covering on the front of the eye) is made up of connective tissue and bathed in lacrimal fluid and aqueous humor. which provides it nutrition, as it does not have access to blood vessels.
*The lens of the eye lies posterior to the iris, and is held suspended by the ciliary suspensory ligament and the ciliary muscle, which allows for "accommodation" of the eye: it allows the lens to change shape to focus on different objects. The lens is made up of onion-like layers of tissue.
Thought 4the day: Horses are like our children to many of us as well as our sole mates. They are our family members who never let us down and help us through the hard times. Life has its twists and turns yet they stay constantly at our sides. Horses are our saviours not just our ridden or inhand steeds. They when having the bond with us will walk through fire just as we should for them. No two hor...ses are he same. We have one young man that craves only for a one on one home where no other will ride him but that person but with the expense of horses now adays this home will be very hard to find once his ready. We have others that are just companions because of trauma that cannot be reversed. One mare has torn shoulder muscles so she can never be ridden but loves wondering about the field as happy as any other horse. We all need to listen to our friends and ask them what they truely need...