Sun Exposure can damage your dog's eyesight

Reposted from an article by our friends at Rex Specs

April 24, 2023 Written by: Amai

Sun Exposure Can Damage Your Dog’s Eyesight. Here’s Why.

If you’ve ever taken a nap while basking in the sun and woken up to a nasty sunburn, you know just how unforgiving the sun can be. Nothing beats being outdoors in the sunshine with your pup, but just like you reach for your favorite shades to keep the sun from your eyes, your dogs deal with the same issue. Sunlight, both UV and visible, can negatively impact your dog’s eye health if they don’t have the right protection. To help you and your dog get the most out of your next adventure without the squinting and long-term side effects, let's break down how sun exposure can impact canine eyesight.

UltraViolet Light Versus Visible Light

Light is all on a spectrum of waves from gamma-rays and X-rays to radio and microwave. Right in the middle is the visible light. Moving along the spectrum, slightly shorter wavelengths (closer to gamma-rays) are harmful UltraViolet (UV) from the sun. Different light, visible or UV affect your dog’s eyesight differently and therefore require different management and treatments.

UV Related Conditions

Just like for humans, UV light or UV radiation can be harmful to your dogs’ eyes and skin. Along with causing painful sunburns and increasing skin cancer risk, these smaller wavelength UV rays can get into eye tissue and degrade function.

Pannus

Pannus or Chronic Superficial Keratitis (CSK) is one of the primary reasons that founders Aiden and Jesse Emilo created Rex Specs — their dog Tuckerman was diagnosed with pannus at age 2. Pannus is a progressive autoimmune disease that impacts the cornea (the clear part of the eye).

UV radiation is one of the key factors that can aggravate and inflame the pannus condition. The inflammation of the condition causes a buildup of scar tissue on the eye and eventually leads to severe visual impairment and blindness. Some breeds like German shepherds, border collies, and greyhounds are genetically predisposed to pannus, but any dog can develop it. Pannus is more likely to develop in dogs who live at high altitudes because of the greater UV exposure.
To learn more about pannus, read our comprehensive guide to pannus in dogs.

The Emilo's Dog, Tuckerman, using Rex Specs in the high alpine of Jackson, WY

Sunburn

Dogs with light-colored eyes or lack of pigment around their noses and eyes are susceptible to sunburns just like humans are. On sunny days especially at higher altitudes UV rays can make your dog’s eyes inflamed and irritated. If you see your dog squinting in the sunlight or having trouble keeping their eyes over after a long day in the sunshine, it may mean their eyes are taking a beating from the sun.
The Emilos’ late Alaskan husky Yaz regularly struggled with her the pigmentless skin around her eyes getting sunburned. This further inspired the couple created Rex Specs to protect her eyes.

Yaz, short for the late, great Carl Yastrzemski, with sunburnt eyes on a float down the Snake River

Cancers

Another more cumulative impact of UV radiation is certain types of skin cancer. Just like with humans, overexposure to the sun damages dogs’ skin and causes cancers like squamous cell carcinoma, malignant melanomas, and hemangiomas. This is particularly true with short-haired dogs or dogs with slight-colored fur.

Visible Light Related Conditions

When it comes to visible light, dogs are arguably more sensitive to it than humans are. Dogs evolved as crepuscular animals meaning they are most active during dawn and dusk whereas humans are diurnal meaning we’re most active during the day. Because of this, dogs’ eyes are more sensitive to light so they can see better in those low light conditions while humans’ eyes are more adapted to brighter light conditions. This also means when dogs spend a lot of time out in that bright visible light, it can make it harder for them to see and even cause damage.

Iris Atrophy

Iris Atrophy is the degeneration of the iris (the colored part of the eye) muscle in the eye. This is a common condition associated with aging that makes it harder for your dog to constrict their pupils, causing them to be more sensitive to bright light. This can make your dog squint more on a sunny day and make being out in bright light less comfortable for your pup.

Day Blindness

Day blindness or achromatopsia is a congenital eye disorder that affects your dog’s cone photoreceptors, which help your dog see in mid to bright light and detect color. With day blindness, your dog’s cones will slowly start to dysfunction and disappear meaning they won’t be able to see during the day. However, the other type of photoreceptors — rods — which work in low light and detect motion aren’t affected, meaning your dog’s night and low-light vision will be fine. Hence the name day blindness.

While this disease occurs through genetics, the impacts are felt through visible light. Your dog may avoid brightly lit areas, prefer to stay inside during daylight hours, or have difficulty finding toys or avoiding obstacles in the daytime.
How to Reduce the Impact of Sun Exposure for Your Dog
While the best way to protect your pup from sun exposure may be to keep them out of the sun, we don’t think the cure should be worse than the disease. Yes, you could leave your dog at home and keep them safe indoors all the time, but your dog deserves to be adventuring, working, and living by your side.

With that in mind, these are our top recommendations to reduce sun exposure while still doing it all.

Use Rex Specs UV eye protection: Rex Specs provide UVA and UVB protection, blocking 99.9% of harmful UV rays.
Stay out of the sun during the brightest times of day: The sun is typically the strongest from 10 am to 4 pm, so if you can get out in the early morning or late afternoon, your dog will benefit.
Keep to the shade: If you aren’t using eye protection and going midday, opting for areas that are shady will help keep the sun exposure down.