Laser Treatments for Pets

Do we use laser in Veterinary Ophthalmology?! Yes! There are many forms and applications laser in veterinary ophthalmology and they include:

- endoscopic laser for glaucoma

- transscleral laser for glaucoma

- diode laser for tumors in the eye

- large anterior chamber cysts

- retinopexy for eyes with a high risk of retinal detachment

More on each of these is outlined below.

Endoscopic Cyclophotocoagulation!!

Find a treatment with more syllables, we dare you!

This form of laser treatment is for glaucoma and targets the ciliary body, the organ inside the eye that produces aqueous.

In this picture the brown on the left is the back of the iris , the finger like projections to the right of the brown sheet are the processes of the ciliary body. The white spots on them are the areas they have been treated with laser. On the far right you can see white strands, these are the lens zonules (ligaments holding the lens in place).

A recent study on Endoscopic Cyclophotocoagulation revealed 90% of dogs had there intraocular pressures controlled at 1 year post procedure and 63% maintained vision. (Sosnowik et al 2024, DOI: 10.1111/vop.13176 )

The success of glaucoma shunts in maintaining vision is higher for patients with primary glaucoma so we typically use endoscopic cyclophotocoagulation for treatment of secondary glaucoma.

Transscleral Cyclophotocoagulation

This treatment provides laser to the ciliary body from outside the eye. It is less invasive (no incisions into the eye) and much faster however the success rate is lower with variable reports from different studies of between 50 and 90% of dogs having their pressure controlled one year later, 50% of dogs having vision one year later . Eyes treated with transscleral laser are more prone to side effects like corneal ulcers or cataracts due to the collateral damage of the laser entering the eye from the outside and the target not being visualized during lasering.

If this technique is less successful then when do we do it?

1) For clients where endolaser or a glaucoma shunt are out of reach financially (it is about 1/3rd the cost

2) Dogs where we have concerns regarding prolonged anesthesia. This can be done under sedation and topical freezing

Iris Diode Photocoagulation

This is where Dr. Osinchuk uses laser to treat early tumors of the iris or iris cysts. Melanocytomas, or tumors of the pigmented cells, are the most common intraocular tumor in the dog. They cause blindness through secondary glaucoma, retinal detachment, and intraocular hemorrhage.

There are two main treatment modalities Dr. Osinchuk offers for these tumors. Smaller earlier lesions can be treated with laser. The laser energy has a thermal effect on pigmented cells, resulting in a process called coagulation necrosis. The mass immediately shrinks with the laser treatment. In the study on iris laser 23 dogs were treated, 18 of them required no further treatment, while 5 required 1-2 more laser treatments (Cook and Wilkie 1999). The second technique is for thicker masses where the laser cannot penetrate, these should be removed surgically.

Laser Retinopexy

This treatment stabilizes small retinal detachments by creating a barrier of scar tissue that prevents the retina from detaching further. It can also be used preventatively in eyes with a high risk of retinal detachment.

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