Interview with Opthalmology Expert, Dr Benjamin Reynolds

About Ben

Ben graduated as a veterinarian from James Cook University winning numerous academic awards during the degree. Since this time at university, Ben’s interest in ophthalmology saw him undertake externships to veterinary ophthalmology centres across Australia, the UK and the USA. Ben was fortunate enough to win an international scholarship in 2018 to allow him to undertake advanced ophthalmology training at North Carolina State University while working as a rotating intern at one of Brisbane’s largest specialist veterinary hospitals.

Ben joined the Eye Clinic for Animals as an ophthalmology intern in January 2019, and completed his ophthalmology residency in 2022. In this time, Ben underwent further training via an externship at the University of California, Davis. Ben has a passion for all aspects of ophthalmic medicine and surgery. Ben has also been assisting in teaching students at the University of Sydney their ophthalmology practicals and tutorials. Ben is one of the registrars at Eye Clinic for Animals, and is preparing to sit examinations to be recognized as a veterinary ophthalmology specialist.

For more information, visit https://eyeclinicforanimals.com.au/

1.    What are the top 5 eye conditions you see in dogs?

• Ulcerative keratitis
• Non-ulcerative keratitis
• Entropion
• Progressive retinal atrophy
• Dry eye disease.

2.    What are the top 5 eye conditions you see in cats?

• herpetic keratitis
• corneal sequestra
• primary glaucoma
• entropion
• hypertensive retinopathy

3.    What are some eye conditions that you feel are highly preventable? 

Primary breed-related entropion. Stricter breeding away from predisposed individuals.

4.    What are some eye conditions that you feel have a better prognosis if diagnosed earlier?

Ulcerative keratitis

5. Eye examinations are not necessarily performed routinely. When it comes to certain dog breeds, which ones would you recommend be done routinely, from what age, and why?

Breeds predisposed to primary glaucoma, as it is an insidious disease that has subtle changes in the early course of the disease, but once it's established then treatment options are limited.

Tonometry
Tonometry is the primary test used to measure intraocular pressure (IOP). Elevated IOP is a hallmark of glaucoma. There are different types of tonometers used:
Applanation Tonometers: Measure the force required to flatten a small area of the cornea.
Rebound Tonometers: Measure the rebound of a small probe from the corneal surface.
Indentation Tonometers: Measure the depth of indentation caused by a standard weight.
A normal IOP in dogs typically ranges from 10 to 25 mmHg. An IOP higher than this range may indicate glaucoma.

Gonioscopy
Gonioscopy is used to examine the drainage angle of the eye, which is often abnormal in dogs with primary glaucoma. A special lens is placed on the cornea to visualize the angle between the cornea and the iris.

Ophthalmoscopy
Ophthalmoscopy allows the veterinarian to examine the interior structures of the eye, including the optic nerve and retina. Changes in the optic nerve, such as cupping, can indicate glaucoma.

Slit Lamp Biomicroscopy
A slit lamp biomicroscope is used to examine the anterior segment of the eye, including the cornea, anterior chamber, iris, and lens. This can help identify signs of glaucoma, such as corneal edema or anterior chamber abnormalities.

Electroretinography (ERG)
ERG measures the electrical activity of the retina in response to light stimulation. It is used to assess retinal function, which can be compromised in advanced cases of glaucoma.

Goniodysgenesis Screening
For breeds predisposed to primary glaucoma, screening for goniodysgenesis (abnormal development of the drainage angle) can be performed. This genetic predisposition is seen in breeds such as the Cocker Spaniel, Basset Hound, and others.

Genetic Testing
Some breeds have known genetic markers for primary glaucoma. Genetic testing can help identify dogs at risk, although this is more commonly used for breeding purposes rather than for individual diagnosis.

Comprehensive Eye Exam
A complete ophthalmic examination by a veterinary ophthalmologist includes assessing vision, pupil response, and the overall health of the eye. This comprehensive approach helps to rule out other potential causes of increased IOP or vision loss.

Imaging Techniques
Advanced imaging techniques like ultrasound biomicroscopy or anterior segment optical coherence tomography (OCT) may be used to provide detailed images of the eye's internal structures and assess the drainage angle and other ocular components.

6.    Can you share any updates that would be relevant to general practitioner veterinarians?

Quantitative vs qualitative dry eye disease. Qualitative dry eye disease is an incredibly prevalent disease but is very rarely assessed for. Whereas everyone knows how to assess quantitative dry eye disease.

Quantitative Dry Eye
Low tear production, the most common form of dry eye, can be either congenital (from birth) or acquired (developing in adulthood). Acquired dry eye is more prevalent and is typically immune-mediated. Certain dog breeds are more susceptible to dry eye. The quantity of tears is measured using a Schirmer Tear Test strip, placed on the eye. Normal tear production in dogs ranges from 15-25mm/min. Dry eye is usually treated with a combination of topical lubricants and tear stimulant drugs such as cyclosporine and tacrolimus. These treatments are required for the lifetime of the dog. Complications like secondary corneal ulcers or recurrent infections may necessitate antibiotic treatment.

Qualitative Dry Eye
This condition is less common and more challenging to diagnose. Poor tear quality causes faster evaporation of the tear film, leading to corneal dryness. Treatment includes topical lubricants with liposomes and immune-modifying drugs. Dry eye often requires lifelong medication. Without adequate treatment, the cornea becomes itchy and sore, increasing the risk of ulceration and infection. While dry eye is a very common condition in dogs, it is usually manageable, allowing them to have healthy, pain-free eyes. If you have any concerns about your dog's eyes, please do not hesitate to contact us.

7.    What treatment do you believe is poorly understood by veterinarians?

The indications of a grid keratotomy or a diamond burr debridement is poorly understood. It should only be used for a specific type of ulcer ie. a superficial chronic corneal epithelial defect (SCCED)

8.    What areas of eye care do you feel VETS could help DRIVE better pet owner education?

Helping owners identify early signs and symptoms of eye pain and discomfort is important for improving patient outcomes.