What is a pterygium? It is an invasive proliferative fibrovascular growth.
Excision of the pterygia was requested by the owner as the dog had difficulty seeing in the right eye and kept rubbing the right eye.
Excision was by electro-surgery under general anaesthesia. In human medicine, there are various sophisticated surgical methods used
I find that many old dogs can survive if the surgery and anaesthesia can be done under 15 minutes. Provided there is care in the anaesthesia and knowledge of emergency resuscitation. The anaesthetic time would be prolonged as there were two pterygia to be excised.
The Divine Powers above threw in an ear haematoma to be operated too. That meant a much longer anaesthetic time.
The longer the anaesthesia, the higher the chances of the old dog dying on the operating table.
This dog needed over 60 minutes of surgery. Would his cornea rupture? That would increase the anaesthetic time.
The dog did not wake up within 2 minutes at the end of anaesthesia.
An antidote (Antisedan) woke him up. He recovered smoothly on Domitor pre-anaesthetic dose, isoflurane gas maintenance and Antisedan anti-dote. He woke up quietly as if he had a good nap.
Fortunately, the mission was accomplished with excellent anaesthesia. This story had a happy ending for everyone. Further info is as follows:
In March 20, 2003, I saw a Shih Tzu puppy with a growth on the right eye for the first time. Was this a rare case of a pterygium? No. It was a Dermoid as it had hairs and was of a different colour. See: Mar 20 03. The Shih Tzu puppy has a "pterygium"?
7 years had passed since I saw the afore-mentioned Shih Tzu puppy with the Dermoid. A real case of pterygium surfaced in February 2010.
She was more knowledgeable than me in specific area affecting this very gentle X-bred dog, as she correctly stated: "My dog has a pterygium," when she first consulted me. She requested me to excise the two bulging growths on the cornea of her dog.
The dog also had glaucoma. She was old. There was a big risk that the cornea might rupture. The bigger risk was death on the operating table as this old dog would be a high anaesthetic risk. Every old dog under anaesthesia is a big risk and deaths from anaesthesia are very unpleasant for the vet as the whole family never forgets nor forgives when the outcome is a dead body. I was very apprehensive that this well cared for and loved family member would die on the operating table as anaesthesia would take a long time to excise two pterygia. As if my worries were not sufficient, the dog also had a right ear haematoma to be operated upon. That meant that the surgery would take over an hour!
The longer the operation, the higher the chances of deaths on the operating table.
"Why do you want the pterygia removed?" I asked the determined owner.
"My dog walked towards her left when the pterygia started to grow fast towards the centre of the cornea. She cannot see from her right eye as the pterygium had obstructed her vision." the owner said. "In addition, she keeps scratching her right eye."
"If the cornea ruptures during excision, I will have to remove the whole eyeball," I said. "Yes," the lady consented. There was this understanding and awareness of the high risk of the cornea bursting when I excise the pterygium when the intraocular pressure was very high. One pterygium was already worrisome. But this dog had two big ones.
"Have you considered enucleation (eyeball removal)?" I asked as glaucoma can be a very painful condition and treatment using eye drops must be given regularly and drug control may become ineffective over time. I don't know much about its glaucoma formation as it was treated by another vet. Glaucoma was controlled by eye drops.
"The other vet has recommended it," she said. "But my family does not want the dog to lose his eye." So enucleation was out of question.
As to what caused such a rapid growth of the pterygia in this beloved dog, it is hard to say. In people, pterygium is said to be caused by ultra-violet light exposure.
It was fortunate that the old dog survived the anaesthesia and went home. "Take good care of her glaucoma," I said to the happy lady as I discovered that the old e-collar was no more worn. I had asked whether she still had the e-collar and she said it was worn out and disposed. "That means that she must wear the e-collar all the time for many weeks and stay out of the sunlight and wind." 7 days later, I would need to review this case.
Pterygia Surgery at Toa Payoh Vets
Haematoma Surgery At Toa Payoh Vets
Toa Payoh Vets webpage and images for this article is:
FOLLOW UP IN 2011
In 2011, the dog's eye was enucleated. The webpage at Toa Payoh Vets is at: