ADVICE

Conjunctival pedicle grafts

Conjunctival pedicle grafts are used to treat deep corneal ulcers.

What is a corneal ulcer?

The cornea is the transparent structure at the front of the eye that allows light to enter. Traumatic injury, most commonly a scratch or foreign body, but also eyelid diseases (entropion), eyelash disease (ectopic cilia or distichiae), infectious agents, or dry eye can damage the surface of the cornea and expose the underlying tissue to cause an ulcer.

If the ulcer is shallow then it will usually heal on its own within a few days or with medical treatment (antibiotic drops, anticollagenase drops, topical lubricant and pain relief by mouth). Sometimes, however, the ulcer may become very deep, and in such cases there is a risk that the eye may rupture. These deep corneal ulcers may require surgery in the form of a conjunctival pedicle graft.

What is a conjunctival pedicle graft?

The conjunctiva is the pale pink tissue that covers the ‘white’ of the eye. It is a thin, relatively strong tissue containing many blood vessels. These properties make it a useful graft material to treat deep corneal ulcers.

Conjunctival pedicle grafting is performed with the patient under general anaesthetic and with the aid of a surgical operating microscope. Using microsurgical instruments, a piece (‘pedicle’) of conjunctival tissue is freed from the ‘white’ of the eye and rotated so that it covers the ulcer. Once in place, it is stitched into the ulcer using very fine dissolvable suture material.

Depending on the case, additional procedures, such as placing a soft bandage contact lens and temporarily stitching the eyelids partially closed, may be performed to help protect the graft and the cornea while it is healing.

What happens after the operation?

The patient might stay hospitalised for a day or two to ensure that the eye is healing satisfactorily or might go home the same day. When they go home, they need to wear a Buster collar for around a week or two so that they cannot rub at the eye. We give a course of pain-relief tablets and antibiotic eye drops. The eye is usually a little uncomfortable and itchy, but this settles after a week or two.

You will need to keep your pet relatively calm and quiet for two to three weeks following the surgery to allow the eye to heal. Usually, this means lead or garden exercise only, no boisterous play, and trying to reduce excitement and barking as much as possible.

How long does the graft stay in place?

The cornea usually takes six to eight weeks to heal beneath the graft, sometimes longer. After that time your vet will usually recommend trimming the graft. In a few cases, however, it may be left in place permanently. Trimming of the graft (in which the base of the graft is cut to remove its blood supply) can often be performed during a check-up examination using topical anaesthetic eye drops. In some cases, however, the patient may need to be admitted for a few hours so that the graft can be trimmed under sedation or a brief anaesthetic.

What is the effect on vision?

Whilst the graft is in place and the eye is healing, the patient will have reduced vision. Following trimming of the graft, vision should improve. There is usually some residual scarring of the cornea, but this scarring usually reduces over a period of months and the patient should regain useful vision. If the scarring is severe, then we may dispense a course of eye ointment (Optimmune or tacrolimus) for a few weeks.