Entropion is another common condition in dogs. In this condition, a portion of the eyelid is inverted such that the normal
eyelid skin and hair makes contact with the cornea. This is usually a congenital or hereditary condition and typically requires
surgical correction. There are several common exceptions. Pugs and Pekingese very commonly have a mild entropion of the medial
lower eyelid. This often results in pigmentation of the medial cornea in these breeds, but typically does not cause signs
of discomfort. Permanent surgery is not recommended in young puppies for several reasons. Some dogs may grow out of the condition
as they age due to differences in the speed of development between the skull and skin. Furthermore, any permanent correction
performed at too early an age may prove to be excessive or insufficient as the dog grows, necessitating a second surgery.
In these cases, temporary eyelid tacking with either suture or surgical staples is effective at keeping the eyelid margin
away from the cornea as the dog grows. Multiple tacking procedures may be necessary until the dog is old enough for surgery.
Eyelid tacking is also useful in treating spastic entropion, a form of secondary entropion induced by a primary corneal injury
or irritation. Relieving the eyelid contact with the cornea will allow the initiating corneal injury to heal and the eyelid
will then return to a normal position. Surgery for entropion involves the removal of skin in appropriate areas to evert the
eyelid margin. This is typically done by the Hotz-Celsus procedure. A strip of skin and orbicularis parallel to the margin
in the affected area is removed and the edges sutured. It is important with this procedure to stay close to the margin (2-3mm)
to minimize scar and ensure that sufficient eversion will occur. Removing too wide a strip of skin may result in cicatricial
ectropion which can be unsightly and difficult to correct. Therefore, it is best to err on the side of caution and aim for
the desired amount or slightly less. It is easier to remove more skin at a later date than to attempt to fix an overcorrected
eyelid. The skin is sutured with 5-0 to 7-0 suture in an interrupted pattern, making sure the knots are a sufficient distance
from the cornea. Many modifications of this surgery have been described depending on the location of the affected eyelid.
Often, a full thickness wedge resection is combined with the Hotz-Celsus procedure. Many forms of hereditary entropion result
from excessive length of the eyelid and thus benefit from shortening. I perform the wedge resection near the lateral canthus
prior to the Hotz-Celsus and have obtained good results with this combination. Important with any eyelid margin resection
techniques is precise apposition of the margin upon closure. This is achieved with a 2 layer closure involving an absorbable
conjunctival layer and non-absorbable skin layer with a figure-8 suture at the margin.
Ectropion is the eversion of a portion of the eyelid away from the cornea such that there is excessive exposure of the conjunctiva.
Surgery is often not necessary for this condition, except in severe forms, such as with severe macroblepharon in Mastiffs,
St. Bernard's, and Bloodhounds. In these cases, a simple wedge resection of the everted areas is effective at improving the
dog's comfort and reducing chronic conjunctival exposure. Cicatricial ectropion can result from overcorrected entropion surgery
or trauma. This is typically corrected with a V→Y plasty but can be difficult due to significant fibrosis of the eyelid stroma.
In most cases of mild ectropion, as is often seen in English bulldogs, does not require correction. The everted eyelid may
result in increased conjunctival irritation and mucoid discharge due to environmental debris collecting in the ventral conjunctival
sac. Treatment with topical corticosteroids is often helpful.
Macroblepharon is an oversized palpebral fissure. In brachycephalic breeds, this results in the "bulgy" eye appearance. As
mentioned earlier, these dogs can have several abnormalities, including lower eyelid medial entropion, lagophthalmos and pigmentary
keratitis. A permanent medial or lateral tarsorrhaphy is a common procedure for reducing the palpebral fissure length and
improve eyelid coverage of the cornea. Lateral tarsorrhaphies are technically easier to perform but medial procedures result
in a better cosmetic appearance. There is risk of damage to the nasolacrimal duct with medial procedures. While multiple surgical
techniques have been described for shortening the palpebral fissure, I find the simplest technique the most effective and
efficient. For a medial tarsorrhaphy, the eyelid margin and medial canthus are excised to a point 1-2 mm from the nasolacrimal
puncta. A 2 layer closure using absorbable suture for the conjunctiva and nylon for the skin is performed. As always, careful
apposition of the margin with a figure 8 suture is important. To relieve tension on the sutures, one or two temporary tarsorrhaphy
sutures through the eyelid margin just lateral to the figure 8 suture is recommended and left in place for several weeks.