Ophthalmology Tea Time Teaser

Sue Manning BVSc (Hons) DVOphthal MRCVS presents an ophthalmology case for your consideration

A  1 year old Siberian Husky presented for examination with a history of right ocular discomfort and recurrent superficial corneal ulceration. Describe your findings. What do you consider the most likely inciting cause and how would you treat this dog?

Right eye

Left eye

Answer.

The right cornea is lack-lustre as evident by the distorted specular reflection (compare with the flash reflection in the left eye). There are distichiasis hairs on both upper and lower eyelids.  Distichiasis is a condition where extra eyelashes arise from or adjacent to the meibomian glands. 

In this dog there is a similar distribution of distichiasis hairs in the left eye, which is not showing any signs of ocular discomfort or corneal pathology.  An alternative cause for the ulceration needs to be investigated including assessment for tear film abnormalities, foreign bodies or adnexal defects, the most likely being an ectopic cilium.  Ectopic cilia are atypical forms of distichia that arise from a follicle inside the meibomian gland, or from follicles near the meibomian duct. In contrast to distichia, ectopic cilia emerge through the conjunctival surface of the eyelid several millimetres from the eyelid margin and are directed towards the cornea. They may be solitary or in small clumps, classically occurring in young dogs and usually, but not always, in the middle of the upper eyelid

Diagrammatical comparison of ectopic cilium at the top and distichiasis hair at the bottom

Eyelid eversion and magnified examination of the palpebral conjunctiva is indicated and in this case confirmed both a stumpy and a long fine ectopic cilium in the lower eyelid

Ectopic cilia are treated by ‘en-bloc’ resection using a chalazion clamp and a no. 11 scalpel blade, scleral trephine or 2 mm biopsy punch.  The surgical site can subsequently be treated with cryotherapy to reduce the potential for recurrence.

Take home message: If a dog with distichiasis presents with ocular discomfort, it is important to perform a full ophthalmic examination and exclude other potential inciting causes before blaming the distichia.  Remember that distichia develop at a young age so if problems develop in an older dog, or if discomfort is unilateral when the distichia appear equally distributed bilaterally, they are unlikely to be responsible.  If there is any doubt, assessment of the response to epilation of the distichia should be assessed before considering permanent removal techniques.