Ophthalmology

Additional Information

Extra information about Ophthalmology

Information about my Ophthalmology appointment

All canine and feline patients, with the exception of pets suffering from diabetes mellitus, should be starved of food on the day of the initial appointment (all pets should have free access to drinking water until the appointment). However, the appointment should not be delayed if starving is not possible (for example if your pet is referred as an emergency). Starving will allow certain investigations and procedures to be carried out on the same day as the consultation if considered necessary by the Ophthalmologist. Please note, however, that most investigations and procedures will likely be scheduled for a later date.

Although information regarding the medication should be provided by the referring veterinary surgeon, clients should bring all medication that has been used in the patient’s eye in the last few days or, if applicable, months. Alternatively a list of the medication may be sufficient.

Most eye medications should be continued throughout the day of examination so that the effect of the eye medication can be assessed. This is particularly important for patients suffering from glaucoma. No medication should be given approximately 30 minutes before the actual appointment.

Information about Glaucoma

What is glaucoma?

Glaucoma is a type of eye disease which occurs when the fluid produced inside the eye cannot drain properly from it. This causes a build-up of fluid and pressure within the eye to unhealthy levels. The pressure build up is not only painful but can cause blindness as it leads to damage of the retina which is required for vision.

What are the different types of glaucoma?

There are many different types of glaucoma, but they can generally be divided into inherited and non-inherited forms.

Inherited (or ‘primary’) glaucoma occurs in certain predisposed dog breeds as a result of mutations in their DNA which are passed from parent to offspring. For this reasons, certain dog breeds, should be examined or, where possible, have a DNA test before they are used for breeding.

Non-inherited (or ‘secondary’) glaucoma occurs when other diseases inside the eye lead to a problem with fluid drainage. There are many causes of secondary glaucoma including trauma, inflammation, a complication of cataract surgery and cancers of the eye.

Identifying glaucoma

Glaucoma may either be gradual or sudden onset. When the signs are gradual (e.g. increased redness and cloudiness of the eye) they are not often picked up by owners until glaucoma is very advanced. Sudden onset glaucoma is easier to spot as the pet becomes suddenly painful and the eye quickly changes appearance and becomes blind. Prolonged increases in eye pressure may lead to enlargement of the eyeball.

Diagnosing glaucoma

Diagnosis of glaucoma requires a complete eye examination and measurement of the eye’s pressure with a device called a tonometer. Often, the primary care vet, may need to seek the opinion of a specialist to aid in diagnosis and form the most appropriate treatment plan.

 Glaucoma treatment

Medical and surgical treatments are available for glaucoma but most glaucomas require long-term management. The choice of medical or surgical treatment depends on the type of glaucoma present.

It is important to decrease the pressure within the eye as quickly as possible in order to minimise damage. Drugs that can draw fluid out of the eye and others that decrease production of fluid are often prescribed. After the pressure is lowered, it must be stabilized to prevent future problems.

Dogs with a painful and blind eye as a result of glaucoma may need it to be removed to relieve pain (this procedure is called enucleation). To read more please click here

The BVA, in partnership with the Kennel Club and the International Sheep Dog Society run an eye scheme through vet practices as a means of identifying inherited eye conditions in dogs before they are used for breeding. This is important to reduce the chance of puppies being born which will develop inherited eye problems later in life.

Our senior Ophthalmologists, James Oliver and Georgina Fricker, are certified Panelists of the BVA Eye Scheme and perform regular testing sessions on Friday mornings. The following tests are offered to breeders:

  1. Routine BVA Eye test checking for a variety of diseases including hereditary cataract and various inherited retinal disease. The routine test is recommended in all pure-bred dogs before they are used for breeding. (Dogs should be at least 6 months old).
  2. Gonioscopy BVA Eye test is performed to assess the risk of developing inherited glaucoma later in life (also known as G = goniodysgenesis/primary glaucoma). Dogs should be at least 6 months old, and it is recommended in certain breeds including: American Cocker Spaniel; Basset Hound; Cocker Spaniel; Dandie Dinmont Terrier; English Springer Spaniel; Flatcoated Retriever; Golden Retriever; Japanese Shiba Inu; Siberian Husky; Spanish Water Dog; Welsh Springer Spaniel; Leonberger and Border Collies
  3. Litter screen this checks for congenital (present at birth) inherited eye problems. (Puppies 6-8 weeks old.)

For more information and prices, please visit BVA website https://www.bva.co.uk/canine-health-schemes/eye-scheme/

There are several types of glaucoma but, in dogs, all forms are associated with high pressure within the eye. It tends to be a painful condition and often leads to blindness despite treatment with medicines (eye drops) or surgery. Sadly, many dogs with glaucoma, need to have their eyes removed on welfare grounds to relieve them of the pain. Some types of glaucoma are inherited and occur because the fluid produced inside the eye cannot drain out. This leads to a build-up of pressure in the eye which causes pain and blindness. In the UK, inherited glaucoma is thought to affect at least 15 different dog breeds. Conservatively, at least 1000 dogs are estimated to have their eyes removed because of inherited glaucoma each year in the UK alone which is a significant welfare problem.

It was the frustrating nature of this condition which prompted our Head of Ophthalmology, James Oliver, to undertake a PhD to investigate the genetics of glaucoma in dogs.

His main aim was to develop DNA tests which breeders could use as tools to prevent puppies from being born/produced which would develop glaucoma in later life and need to have their eyes removed.

James’ PhD was only possible due to generous funding from the charity Dogs Trust and was supervised by Dr Cathryn Mellersh who runs the Kennel Club Genetics Centre at University of Cambridge (previously Animal Health Trust).

James’ research led to eight different scientific publications and was instrumental in demonstrating the cause of glaucoma in four different dog breeds. Dog breeders can now use a simple DNA test to find out if their dogs carry the faulty glaucoma genes before they are bred from. Therefore, they can prevent the faulty gene being passed on to any offspring. Eventually, through careful breeding, these faulty genes can be eliminated along with the glaucoma. These DNA tests, and many others, are offered by Cambridge University (www.cagt.co.uk).

The Ophthalmology Team at DWR continues to collaborate with the Kennel Club Genetics Centre at Cambridge and they are currently working on several exciting projects together. All of these are focussed on understanding the cause of various inherited eye diseases with the aim of developing DNA tests which can be used to eventually eliminate these causes of blindness in dogs. If you own a dog which has been diagnosed with an inherited eye disease and you would like to contribute a DNA sample for further research then please email bryan.mclaughlin@thekennelclub.org.uk

During James’ PhD he examined over 1,000 dogs at various events all over the UK to assess them for inherited glaucoma. It was during one of these events that James came across Monty a delightful Basset Hound! James diagnosed Monty with a type of inherited glaucoma that had never been reported in the Bassett Hound before (primary open angle glaucoma). The discovery of Monty was quickly followed by that of other Basset Hounds with this condition. Within a few months a DNA test was developed which Basset Hound breeders could use to prevent them from unwittingly using dogs with the faulty gene for breeding. Thus, by using the DNA test properly, no more Basset Hounds need be affected by this type of glaucoma again!

 

Information about Diabetes and Cataracts

A cataract is an opacity (or cloudiness) of the lens in the eye. The lens is normally a transparent, spherical structure that focuses light onto the retina. A cataract therefore blocks the light from getting to the retina. In the early stages this can result in blurring of vision, but as the cataract progresses it can result in complete blindness.

You can read more about cataracts here 

If your pet needs to be referred to us from your vet then we can perform Cataract surgery (phacoemulsification and intraocular lens placement) to try to prevent them going blind.

 

Unfortunately, nearly all diabetic dogs will develop cataracts and go blind. Diabetic dogs have high blood sugar levels which leads to high sugar levels inside the lens. This excess sugar in the lens draws water into it which causes the lens to swell and for cataract to develop. Diabetic cataracts can develop rapidly and cause a lot of inflammation within the eye requiring urgent surgery. It is very important that dogs with diabetic cataracts are referred early to improve the chance of successful surgery. Fortunately, cataract surgery is very successful if performed early enough with almost 100% dogs regaining vision.

Cataract surgery is a very specialist procedure and should only be performed by suitably trained and qualified veterinary surgeons. Diabetic dogs also have very specialist health needs and need particular care under general anaesthesia. For these reasons, cataract surgery should be performed in a centre with specialists in anaesthesia and internal medicine to ensure all the dog’s health needs are catered for.

You can read more about cataracts here 

If your pet needs to be referred to us from your vet then we can perform Cataract surgery (phacoemulsification and intraocular lens placement) to try to prevent them going blind.