Retinal Diseases

What is the retina?

The retina is a thin structure in the back of the eye that contains the cells responsible for vision. These cells detect light and shadows and send signals to the brain via the optic nerve to create a recognizable image.

How will I know if my pet has a retinal issue?

Since the retina is necessary for vision, retinal problems most often manifest as either partial or complete visual deficit. The most common signs are bumping into walls and furniture, inability to fetch toys, and being easily startled. Sometimes visual problems are noted only in certain lighting conditions (i.e. light vs. dark or day vs night). In animals with only partial vision loss or in those that become blind in only one eye, it is much more difficult to detect a problem at home because animals can compensate extremely well.

Intraocular Inflammation

What is uveitis or intraocular inflammation?

Uveitis is the term used for inflammation of the uveal tract of the eye (the iris, ciliary body, and choroid). In order to understand uveitis, it helps to first understand the basic anatomy of the eye. The eye is made up of three primary layers of tissue. The outer layer enclosing the eye is made up of the cornea (the clear part at the front of the eye) and the sclera (the white of the eye). The inner layer is the retina, which primarily consists of nerve tissue. The middle layer is called the uveal tract, and it is rich in blood vessels, which makes it very susceptible to diseases present in other parts of the body. The uveal tract is composed of the iris (the colored part of the eye), the ciliary body (a structure which produces the fluid inside the eye), and the choroid, which nourishes the retina in the back of the eye.

Keratoconjunctivitis sicca (KCS) or “Dry Eye”

What is KCS?

Keratoconjunctivitis sicca is a disease characterized by inflammation of the cornea and conjunctiva (pink tissue covering the whites of the eyes and the inside of the eyelids) secondary to inadequate tear production by the tear glands. When an inadequate level of tears is present, debris and bacteria (that are normally washed away by the tears) build up and a thick mucous discharge forms. The disease is usually caused by inflammation of the lacrimal glands, but can also be caused by the toxic effect of certain drugs on the lacrimal glands or by lack of nerve innervation to the lacrimal glands.

Glaucoma Management

What is glaucoma?

Glaucoma is one of the leading causes of vision loss in dogs and people. It is less common in cats and horses, but can occur in any species. Glaucoma is a painful disease in which the pressure inside the eye increases and causes damage to the structures responsible for vision. Elevated intraocular pressure results in the clinical signs that you may have noted at home (cloudy eye, redness, squinting). The longer the pressure in the eye is elevated, the more damage occurs to the structures in the eye responsible for vision (especially the retina and optic nerve), eventually resulting in permanent blindness.

Eyelid Surgery

lid mass Several eyelid abnormalities benefit from surgery. Surgery is utilized to correct inherited or acquired conformational abnormalities such as entropion, macroblepharon (excessive eyelid length), ectropion or eyelid agenesis, to remove tumors of the eyelids, or to treat distichiae and ectopic cilia.

What kinds of eyelid issues could my pet have that require surgery?

Entropion is inversion or ‘rolling in’ of the eyelids, leading to contact between eyelid hairs and the cornea. This contact is irritating and uncomfortable, and causes corneal ulceration, scarring, and pain. In contrast to entropion, ectropion is eversion or ‘rolling out’ of the eyelids and is often seen in combination with macroblepharon. Ectropion results in exposure and irritation of the conjunctiva and cornea due to evaporation of the tear film and collection of dust and debris. These conformational abnormalities are most often inherited and can be seen with excessive eyelid length, weak eyelid cartilage, extensive facial folds, a particular skull conformation, or the anatomy of the orbit.