The retina

The retina is a thin, sheet-like structure that lines the back of the eye. Cells in the retina are responsible for turning light stimulus into an electrical signal that then gets transmitted to the brain which interprets the signal as a visual image.

The retina sits on top of a layer of cells called the retinal pigmented epithelium (RPE) which in turn sits on top of a highly vascular structure called the choroid. The retina obtains much of its oxygen and nutrients from the choroid and the RPE is responsible for renewal processes that keep the retina functioning.

Retinal detachment

A detachment of the retina means that the retina has detached from the underlying retinal pigmented epithelium and choroid. Because these structures are important in the health of the retina, detachment leads to an inability of retinal cells to function properly.

The result is blindness as well as eventual death of the retina.


There are many causes of a retinal detachment. 

  • In general, it can be pushed off by fluid or cellular build up under the retina such as in cases of high blood pressure, bleeding disorders, trauma, infectious and immune-mediated inflammation, or some tumours.
  • It can be pulled off by bands of organizing inflammatory debris that may form in the fluid-filled space in front of the retina.
  • Holes or tears can form in the retina that progress into full detachments.

Signs of a retinal detachment

The main clinical sign of a retinal detachment is a loss of vision in the affected eye. As well, the pupil usually becomes dilated (enlarged).

The loss of vision may not be noticed if the detachment only occurs in one eye as the animal may compensate for the loss of vision by using the good eye.


Treatment will depend on the cause of the retinal detachment. High blood pressure and infectious or immune-mediated inflammatory disease require specific medical therapy.

Contracting bands that are pulling the retina off and holes or tears that progress to retinal detachment require surgical reattachment surgery.

Retinal Reattachment Surgery

Retinal reattachment surgery is a technically demanding surgery that is performed under a general anesthesia using a special operating microscope.

In general, the fluid that normally sits in front of the retina is removed, and the retina is then replaced into its normal position.

Next, a laser is used to make small scars between the retina and the underlying structures in order to help hold it in place.

The fluid that was removed is replaced with sterile silicone oil, which remains within the eye forever.

Success Rate

Retinal reattachment surgery is a relatively new procedure. The rate of successful reattachment of the retina is high. Successful return of vision, however, depends on how long the retina has been detached and how much damage has occurred to it during that time.

The longer the retina is detached, the more permanent damage that is done. Reattachment should be performed within four weeks of the detachment in order to return some functional vision.

We recommend performing retinal reattachment as soon as possible after the diagnosis of detachment. In our experience, the long-term visual outcome following retinal reattachment surgery is less than 50 per cent.

Possible Complications

Complications can occur during or after surgery. Complications during surgery may include:

  • bleeding into the eye
  • damage to the retina itself.

Complications following surgery can include: 

  • infection
  • elevated intraocular pressures (post-operative glaucoma)
  • cataract formation
  • corneal ulceration
  • displacement of silicone oil into the front of the eye
  • failure of vision to return.

Complications often require a second surgery to remove the eye or place an intrascleral prosthesis.

Deciding on Surgery

How do I know if my animal is a candidate for retinal reattachment surgery?

Examination by a veterinary ophthalmologist is required to decide if your animal is a candidate for surgery. Examination by your veterinarian is the first step followed by referral to a veterinary ophthalmologist.

The type and the cause of retinal detachment must first be determined and this may require various types of diagnostic testing such as blood pressure measurement and blood tests to rule out infectious diseases.

How long will my animal be in hospital after surgery?

Your animal will need to be in the WCVM Veterinary Medical Centre the day prior to surgery for pre-surgical and pre-anesthetic assessments and will usually go home during the afternoon of the surgery.

You will be expected to return the following morning for re-evaluation. Several re-check examinations will usually be required over the next year and these will be scheduled based on the individual needs of the animal.

Appointments and Referrals

Animal Owners

This is a referral-based service. You will need to have your veterinarian submit a referral form to the Veterinary Medical Centre before you can make an appointment with this clinical service. 

Your local veterinarian may choose to consult with the WCVM ophthalmology service regarding your animal’s condition and possible treatment protocols. At that point, your veterinarian may decide to refer your animal to the VMC's ophthalmology service.

Referring Veterinarians

Submit an online referral form.

If you have any questions about a referral patient, please contact WCVM Ophthalmology Service:

 Emergency services available 24/7

Emergency services are available for acutely ill or seriously injured animals.