Distichiasis [Extra Eyelashes]
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Distichiasis is an eyelid abnormality in which one or more extra eyelashes emerge from openings of the meibomian glands along the eyelid margin. These hairs grow from an abnormal position behind the normal row of lashes and can point toward the eye. The condition is inherited in several breeds, although the exact mode of inheritance is not established for every affected population.
Some distichia are very fine and soft and never cause a problem. Others are stiff or positioned so that they repeatedly rub against the cornea. Irritation can produce excessive tearing, blinking, squinting, redness or rubbing at the face. Persistent contact may damage the corneal surface and create an ulcer. Corneal ulcers are painful and, if deep or infected, can threaten vision.
The number of abnormal hairs varies widely. A dog may have a single distichia in one eyelid or many hairs affecting both eyes. Fluorescein stain is used when corneal ulceration is suspected.
Distichiasis should be distinguished from ectopic cilia, in which a hair emerges through the inner conjunctival surface of the eyelid rather than the lid margin. Ectopic cilia are often more painful because the hair points directly at the cornea. The clinical importance of distichiasis depends on whether the hairs actually contact and irritate the eye.
Not every extra eyelash causes disease. Problems arise when a hair is sufficiently stiff or is positioned so that it repeatedly contacts the corneal surface, producing tearing, squinting, inflammation or ulceration. Dogs with soft hairs may show no discomfort at all.
Magnification and good lighting are important because some distichia are pale or very fine. The cornea is assessed at the same time for areas of irritation, scarring or ulceration. Fluorescein staining is performed if the dog is squinting, tearing or rubbing the eye.
Screening & Early Detection
Eye examination is the practical screening method for distichiasis. Predisposed puppies should have the eyelid margins inspected during routine health checks, and formal ophthalmic examination may be recommended for breeding dogs. Because additional abnormal lashes can emerge later, repeat examinations during growth and adulthood are more informative than one check at eight weeks.
The examiner looks closely along the meibomian gland openings for hairs emerging behind the normal eyelashes.
Seek prompt assessment for persistent blinking, a watery eye, redness, face rubbing or sudden light sensitivity. These signs suggest that a hair may be damaging the cornea even if the eyelid looks normal without magnification.
There is no universal DNA test for distichiasis. Breeding screening therefore relies on repeated clinical eye certification and recording affected relatives. A dog with apparently harmless distichia still has the anatomical trait, so its breeding significance should be considered separately from whether that individual currently needs treatment.
New lashes can also become apparent as the dog matures, so a normal early puppy examination does not always exclude later development. Diagnosis is made by close inspection of the eyelid margin, usually with magnification.
Treatment & Management
Distichia that do not contact the cornea and cause no discomfort may simply be monitored. Treatment is indicated when hairs produce persistent irritation, corneal ulceration or recurrent eye pain. Plucking an abnormal lash can provide temporary relief and may help confirm that it is responsible for the symptoms, but the follicle remains and the hair usually regrows.
More permanent treatment destroys or removes the abnormal hair follicle. Techniques include electroepilation, cryotherapy or laser treatment, chosen according to the number and position of hairs and the equipment available. These procedures are usually performed under anaesthesia or heavy sedation because precision is essential around the eye. Multiple treatment sessions may be required if some follicles survive or new distichia emerge later.
Any corneal ulcer is treated at the same time. Medication may include topical antibiotics, pain relief and protective measures, with follow-up staining to confirm that the cornea has healed. Prevent the dog rubbing the eye during recovery.
The outlook is generally excellent once irritating hairs are permanently controlled. Recurrence does not necessarily mean the procedure was performed badly; follicles can be difficult to destroy completely and additional abnormal lashes can develop over time. A return of squinting, tearing or redness should therefore trigger re-examination rather than repeated home plucking, which does not solve the underlying problem.
Treatment is unnecessary for non-irritating lashes but appropriate when discomfort or corneal damage is present.
Breeds or species affected
American Cocker Spaniel
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American Staffordshire terrier
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Beagle
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Boxer
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British Bulldog
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Chesapeake Bay retriever
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Pug
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English Cocker Spaniel
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Curly-Coated Retriever
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Flat-coated retriever
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French bulldog
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Golden retriever
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Lhasa apso
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Miniature Poodle
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Pekingese
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Toy Poodle
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Retriever (flat or curly coated)
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St Bernard
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Shetland sheepdog
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Shih tzu
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Sussex spaniel
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Tibetan terrier
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