Disease of the equine posterior segment.

This research paper provides an in-depth review of the appearance of the equine fundus and studies how to distinguish between normal variations and diseases. It covers various pathologies that can be identified near the optic nerve head and updates the descriptions of ocular fundic abnormalities.

Equine Fundus Inspection

• This piece of research presents an exhaustive review of the appearance of the equine fundus. The fundus is the interior surface of the eye, opposite the lens, and includes the retina, optic disc, and the macula. In horses, the fundus appearance may exhibit variations that are part of the animal’s normal physiology or indicate disease conditions.
• The researchers are investigating ways to tell normal variations apart from pathologies, which might aid in the accurate diagnosis and treatment of equine ocular diseases.

Location of Pathological Lesions

• The study reports that most pathological lesions in horses’ eyes are identified close to the optic nerve head, a crucial part of the eye where nerve fibers from the retina converge to form the optic nerve. Lesions commonly exhibit depigmentation or hyperpigmentation.

Aspects of Pigmented Bands

• Depending on their configuration and appearance, linear pigmented bands in the equine eye could reflect different conditions— the course of the vortex veins, the transition from the tapetal (a reflective layer in the eyes of many vertebrates) to the nontapetal fundus, or diseases such as chorioretinitis (an inflammation of the choroid and retina of the eye) or equine motor neuron disease (a degenerative disease affecting nerve cells).

Choroidal Vasculature and Hemorrhages in Horses

• In color-dilute or subalbinotic horses, the choroidal vasculature (the network of blood vessels in the choroid of the eye) is apparent and should be differentiated from hemorrhage.
• The paper states that retinal hemorrhages are common in foals and can occur independently of hypoxic ischemic encephalopathy, a condition caused by reduced blood and oxygen supply to the baby’s brain near or during birth.

Significance of Retinal Cysts

• Retinal cysts might indicate more significant diseases in the eye such as anterior segment dysgenesis, a developmental disorder that affects the front portion of the eye.

Prominence of Gray or Tan-Colored Material

• The prominence of gray or tan-colored material on or near the optic nerve head could represent various conditions – traumatic optic neuropathy (an uncommon, yet serious, condition that occurs after head or facial trauma), benign optic neuropathy, proliferative optic neuropathy, or actual neoplasia (new and abnormal growth of tissue).

This paper presents updated descriptions for the various ocular fundic abnormalities to aid more accurate diagnoses and to provide information that may lead to better management and treatment of equine eye diseases.