What is Iris Bombe?
Iris bombe causes ocular pain and a mild to a severe decrease of vision. It is not more commonly seen in any specific breed, gender, or age of the dog. The most marked sign of iris bombe is the irregularity in the appearance of your dog’s eye. The iris may appear a marbled, or different color, and the pupil may appear a different shape. Iris bombe can be very serious, and may cause an acute attack of angle-closure glaucoma. Glaucoma is a condition in which the optic nerve is destroyed by elevated intraocular pressure and is one of the leading causes of blindness in dogs. It is incredibly important that you bring your dog in for veterinary treatment as soon as you notice symptoms, as it may be the difference between your dog maintaining or losing his or her sight.A development of fluid in the posterior chamber of your dog’s eye causes a forward bulging of the peripheral iris due to an irregularity of the synechia, or the adhesions between the iris and the rest of your dog’s eyeball. The cause and primary discomfort of iris bombe are intraocular pressure.
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Symptoms of Iris Bombe in Dogs
- Excessive squinting
- Corneal lesions
- Excessive production of tears
- Glaucoma, seen as a clouding over of the eyes
- Variation in lens color
- Decreased reaction to light
- Decreased sight
- Inflammation of the eye
- Subconjunctival hemorrhage, or ocular surface blood vessels on the whites of the eyes
Causes of Iris Bombe in Dogs
- Chronic infection
- Side effect of surgery
- Ocular wound(s) or injuries
- Corneal ulcer
Diagnosis of Iris Bombe in Dogs
The veterinarian will administer a meticulous physical examination and a round of routine testing to assess your dog’s overall health. This should include a complete blood count, chemical blood profile, and urinalysis will check for irregularities in your dog’s bodily functions. Diagnosis for iris bombe will depend upon an ophthalmic examination of the structures of your dog’s eye in order to determine the position of the iris and the presence of possible glaucoma. A tonometry test will be performed to measure the intraocular pressure, which will be elevated if your dog has iris bombe, but the level of pressure will indicate the severity of your dog’s condition. Tonometry measures pressure in millimeters of mercury, or mmHg. The normal range of intraocular pressure is between 15 to 25 mmHg; intraocular pressure above 50mmHg will cause glaucoma and can quickly result in blindness. Tonometry is often measured using a rapid air puff to flatten the cornea and detecting the force of the air jet as it hits the surface of the eye.
There are several other conditions that may look like iris bombe to you at home during self-diagnosis, although it's important to note that only a qualified veterinarian will be able to determine the proper diagnosis. Other conditions to consider include intraocular neoplasia, cataracts, persistent pupillary membranes, iris hypoplasia, and conjunctivitis.
Treatment of Iris Bombe in Dogs
The irregularity in your dog’s iris may be treated through laser surgery, particularly when it is causing angle-closure glaucoma. Treatment of glaucoma is designed to control symptoms, as it can rarely be cured. In addition to laser surgery, the pressure can be treated through osmotic diuretics to decrease intraocular pressure, beta blockers to decrease the production of fluid (may cause side effect of decreased heart rate), carbonic anhydrase inhibitors to suppress the production of aqueous humor (may cause side effect of panting and decreased appetite), prostaglandins to decrease the size of the pupil and increase uveo-scleral outflow, corticosteroids and non-steroidal anti-inflammatories to decrease inflammation, and miotics to constrict the pupil (may cause side effect of ocular irritation). In addition to treating the secondary glaucoma, if treatment can effectively reduce the pressure building up in the posterior chamber of the eye, the iris should be able to return to its original position.
Recovery of Iris Bombe in Dogs
Whether your dog is treated through surgery or medication or a combination of the two, follow up care and checkups will be integral to a healthy recovery and maintenance of sight. Since there are many possible medications that may be prescribed, watch for possible side affects and worsening of your dog’s condition. If you notice any negative changes, consult your veterinarian, who may recommend a change in the course of medication.
The likelihood of your dog retaining her sight depends upon how far your dog’s condition has progressed before you seek treatment. If you bring your dog in early and do not take a wait and see approach for treatment while his sight is still intact, your pup will have a much better chance and/or odds of full recovery.