Dogs absolutely have eyelashes, though they are often referred to by the more technical term, cilia. These structures serve a protective role for the eye, much like human eyelashes, but they differ significantly in placement and appearance. Unlike the prominent, uniform rows found in people, canine cilia are typically less noticeable. Understanding these hairs is important because they are directly linked to overall eye health and can be the source of several common medical issues.
Understanding Canine Eyelash Anatomy
The true eyelashes, or cilia, are primarily located on a dog’s upper eyelid margin, often growing in two or four irregular rows. The lower eyelid, in contrast, usually has only fine, short hairs or sometimes none at all. The appearance and length of a dog’s eyelashes vary dramatically depending on the breed. Dogs with long facial hair, such as the Shih Tzu or Lhasa Apso, often have prominent eyelashes. Conversely, many short-haired breeds may have cilia that are barely visible. Anatomically, the eyelids also contain specialized glands, including the Meibomian glands, which produce the oily component of the tear film.
The Purpose of Dog Eye Cilia
Canine cilia function as the first line of physical defense for the sensitive surface of the eye. These short, sturdy hairs create a barrier that helps to shield the eye from environmental elements such as dust, dirt, and small debris. The cilia work to deflect particles away from the cornea, the transparent outer layer of the eyeball. Beyond the physical barrier, these hairs also play a sensory role, acting like miniature feelers. When an object comes close enough to touch the cilia, it triggers a rapid, protective reflex. This sensory input causes the dog to blink quickly and completely, a reflex known as the menace response. The swift closure of the eyelids helps to distribute the tear film across the eye, washing away any small irritants.
Medical Conditions Related to Eyelash Growth
While normal eyelashes are protective, abnormal growth patterns can lead to painful eye conditions.
One of the most common issues is Distichiasis, a genetically inherited condition where extra eyelashes, called distichiae, grow from the Meibomian glands along the eyelid margin. These aberrant hairs can be soft and harmless, but if they are stiff, they can rub against the cornea, causing irritation and excessive tearing.
A more severe condition is Ectopic Cilia, which occurs when a hair grows from the Meibomian gland but emerges through the inner lining of the eyelid, the conjunctiva, rather than the margin. Since these hairs grow directly toward the cornea, they cause discomfort, often resulting in corneal ulcers. Affected dogs may show symptoms like squinting, pawing at the eye, and excessive discharge.
The third main issue is Trichiasis, where hairs that grow from a normal location—either the regular cilia or the surrounding facial hair—are misdirected and touch the eye’s surface. This is often seen in breeds with prominent facial folds or long hair, such as Pekingese or Shih Tzus, and can cause chronic irritation and tear staining. Treatment for these eyelash disorders often involves permanent removal of the hair follicle, typically through procedures like cryotherapy, which uses freezing to destroy the follicle, or surgical excision.