Indolent Ulcer

WHAT IS AN INDOLENT ULCER?

The cornea is the transparent front covering of the eye just like the glass of a camera. It is less than 1mm thick and consists of several complex layers. An indolent ulcer is a defect in the cornea that is unable to heal due to a layer of denatured tissue on the surface of the eye. The cornea is well supplied with nerves and therefore these ulcers are quite painful.

WHAT CAUSES AN INDOLENT ULCER?

Indolent ulcers are most frequently seen in older dogs. The specific cause is unknown. Normally, when there is a defect or ulcer on the surface of the eye, the cells at the outer edges slide into the center and healing is complete in about 5-7 days. With an indolent ulcer, these cells cannot slide into the defect due to loose tissue surrounding the outer edges of the wound. Imagine being on the beach and digging a hole in the sand (ulcer) and every grain of sand is a corneal cell. If these grains of sand were pushed into the hole they would eventually fill it in. But what if you had the Himalayan Mountains surrounding this hole in the sand. How could the grains of sand get over the mountain?

HOW ARE INDOLENT ULCERS TREATED?

There are several methods of treating indolent ulcers: Grid or Striate Keratotomy/Punctate Keratotomy A short acting sedative and topical anesthetic drops are required to perform these procedures. The loose “flaps” of healing tissue at the edges of the ulcer are gently scraped away and then a small needle is used to either scratch a grid pattern over the surface of the ulcer (striate keratotomy) or to make small puncture holes (punctate keratotomy) through the dead tissue to the healthy cornea below. The intention of the procedures is to create openings through the denatured layer down to the healthy cornea so the healing edges are able to root themselves down. The success rate with these procedures is about 80%. Another procedure is the creation of these openings with an ocular cautery. After these procedures a contact lens is placed on the eye to act as a protective bandage that we remove in 10-14 days. Therefore, if the ulcer still does not heal, a superficial keratectomy (explained below) will need to be performed. Superficial Keratectomy This surgery requires a general anesthetic. Under the operating microscope, a thin layer of cornea is completely removed, including the ulcer and the denatured tissue, leaving only healthy cornea. After surgery, a soft contact lens is placed on the eye (to act as a bandage), and the lids are temporarily held closed with one stitch to protect the eye and hold the contact lens in place. Your pet will also need to wear a plastic elizabethan collar for about 1 week (to prevent rubbing at the eye) until the stitch is removed. The success rate for this procedure is very good at 99.9%. Once healing begins, the formation of scar tissue on the cornea is common, this is minimized with a course of anti-inflammatory drops beginning within the first 1-2 weeks after surgery.  

WHAT WILL I NEED TO DO AT HOME?

  • When using eye drops, be sure the medication is placed directly onto the eyeball. Wait 10 minutes between different drops so as not to flush out the previous medication before it has been absorbed. If you are required to use ointment, always apply it AFTER all the drops have been given.
  • Keep the elizabethan collar on at all times. It only takes a moment for a rubbing paw to do damage.

Wipe away any discharge from the eye with a clean, moist Kleenex or washcloth.