Dogs’ eyes, similar to those of most animals, have the same function and design as humans’ eyes. Threats to healthy eyes include injuries, conditions and diseases.

Both are thus subject to many of the same age-related changes and ailments. This means that your beloved pooch could one day suffer from a variety of ocular diseases, making it crucial to attend closely to any changes in their vision and the condition of their eyes.

Some eye conditions are genetic but many develop because of other health challenges. Diabetes, high blood pressure, and certain cancers, which have all become more common among older pets, can trigger eye disease.

Dogs often exhibit numerous indicators that they are troubled by eye problems. These could be physical, behavioural, or both together. It is known that many problems start with the ‘red eye’ symptom. You may notice colour changes on or inside the eye. Squinting, tears, and rubbing at the eyes, face, or around the head may also increase. Haziness in the eye, lots of blinking, and a nasty discharge, especially if it is gooey, could signal a disease.

Several eye diseases are commonly found among dogs and many of them can cause discomfort, sight impairment, or loss of vision. The most frequently occurring diseases endured by our canine chums are dry eye, cataracts, and glaucoma. Some eye conditions may have a genetic origin while the onset of others is linked to age or being exposed to damaging environmental factors and affect most dogs sometime in life.

Common dog eye diseases include cataracts, dry eye, and glaucoma.

Glaucoma damages the optic nerve due to increased pressure in the eyeball. This is a severe condition that can cause blindness. In humans, glaucoma mostly progresses slowly, but domestic canines get congestive or closed-angle glaucoma that develops in older days. When eye disease is identified early, treatment can manage the pain and save many dogs’ eyesight. The symptoms include swelling, redness, and pain. It should be diagnosed as early as possible and treated to avoid permanent loss of sight. Canine glaucoma can be treated surgically or with medication prescribed by your veterinarian.

Cataracts can be caused by age, injury, or certain diseases. With age, many dogs develop a haziness in the eye and this is termed nuclear sclerosis. This is a less serious condition and is seldom treated. Cataracts also appear as cloudy areas on the lens of the eye but these create physical barriers that prevent sufficient light from reaching the optic nerve and this can cause vision loss. The light that does enter is distorted and often gives a halo effect to objects. Other symptoms of cataracts include sensitivity to light, and difficulty seeing in dim light. Nowadays the condition is frequently treated by phacoemulsification which involves using ultra-high vibrations (40,000 cycles a second) to break down the offending structure. The remnants are then removed through a tiny incision. This treatment could include implanting a replacement lens that should restore virtually normal vision. For dogs, this highly successful procedure is the same as for humans.

The condition known as dry eye is caused when not enough moisture is produced to lubricate the eyeball. This particularly affects the cornea, which is exposed to the air’s drying effects. Symptoms of dry eye are squinting and pinching the lids shut. Usually, there is viscous discharge because insufficient moisture is exuded from the tear duct. Fortunately, the treatment is simple and effective depending on how cooperative your dog is. Basically, tear production is stimulated by using topical eye drops. In severe cases, antibiotics may be required to treat secondary infections.

Often owners have difficulty detecting if their pets have poor vision because dogs cope very well with any remaining sight. Timeous professional examination by a veterinarian is critical for diagnosing and treating eye ailments successfully to retain as much of your dog’s vision as possible.

Please contact your veterinarian at once if you’ve noticed significant changes in your pet’s ability to see. The earlier the diagnosis is made and treatment is begun, the more likely it is that you’ll be able to prevent potential long-term damage to your four-footed best friend’s eyes.

Cats have very unique and beautiful eyes. They can detect much more light than we can, however, their colour vision is limited. Threats to healthy eyes include injuries, conditions and diseases.

The following are considered common eye conditions or problems in felines:

1. Allergies/Irritants

   
   This is a tricky one since symptoms are very similar to other conditions and problems. So, if you notice redness or discharge (especially if it doesn’t go away or gets worse) visit a vet.

2. Cataracts

   
   The eye lens is the typically transparent structure in the centre of the eye behind the pupil. Cataracts, that cause the lens to appear milky white or cloudy gray, can result in vision problems, including blindness.

3. Corneal Ulcers

   
   The eye’s clear surface tissue is called the cornea which admits light into the eye. Open sores in this area are called corneal ulcers. Causes include injury, infection, tear production issues or other abnormalities. Signs and symptoms include cloudy cornea, pain, squinting, redness and in some cases discharge.

4. Discolouration of the Iris

   
   Iris melanosis manifests as brown ‘freckles’ on the coloured rim of tissue around the pupil typically in cats around 7 years and older. When a dark pigment appears on the iris it can be a sign of iris melanoma (a type of cancer).

5. Glaucoma

   
   Glaucoma in cats is an emergency. When eye fluids are unable to drain, eye pressure increases. Affected cats are usually in pain and can lose their vision and even their eyes. There are many causes. Signs and symptoms include cloudy, red, weepy and sometimes enlarged eyes.

6. Infections

   
   Causes: bacteria, fungi, parasites and viruses. Possible signs and symptoms: discharge, redness, swelling, rubbing, squinting, sneezing and nasal discharge.

7. Trauma

   
   Physical injury (a cut, puncture or scratch) can be caused by accidents, fights and materials getting stuck in the eye. Signs and symptoms: redness, swelling, pain, discharge and visible damage.

Other diseases include:

• Conjunctivitis (pink eye)
• Dendritic corneal ulcers
• Nasolacrimal duct obstruction (NLDO)
• Uveitis

If you think your cat might have an eye condition or injury, visit a vet.

Dogs’ eyes are very important organs that help them form images of the world. Threats to healthy eyes include injuries, conditions and diseases.

The following are considered common eye conditions in canines:

1. Blepharospasm
   
   

   Blepharospasm means involuntary blinking or twitching of the eyelids. Rather than a condition or disease, blepharospasm is a clinical indicator of an eye-related problem. Signs and symptoms of blepharospasm include red, swollen and/or itchy eyelid(s); spasmodic blinking; scratching or rubbing of the face or eyelids; eye discharge; crusty or flaky eyelid skin; and pimple-like bumps.

2. Cataracts
   
   

   The eye lens is the transparent structure behind the pupil. Cataracts cause the eye lens to appear cloudy or bluish-gray. The condition can cause pressure and vision problems, including blindness.

3. Cherry Eye
   
   

   Dogs have one hidden and two visible eyelids. The concealed one hides in your dog’s inner eye corner. Ligaments keep it in place but an inherited weakness can cause it to ‘pop’ out. Cherry eye requires treatment.

4. Conjunctivitis (Pink Eye)

   
   The conjunctiva is a mucous membrane found inside the eyelids. When it becomes inflamed we call it conjunctivitis, or pink eye. There are several causes. Signs include blepharospasm (see above), redness, eye discharge and swelling.

5. Corneal and Scleral Wounds

   
   The eye’s outer, clear tissue (that sits in front of the iris and pupil) is called the cornea. The white outer layer of the eyeball is called the sclera. Both are delicate and certain objects or incidents can cause corneal or scleral abrasion. Types of wounds include cuts, punctures and ulcers. A red, watery eye is often a sign of injury.

THAT’S IT FOR PART 1!

Find out more about the following conditions in Part 2:

• Entropion
• Glaucoma
• Keratoconjunctivitis Sicca (Dry eye)
• Lens Luxation
• Progressive Retinal Atrophy (PRA)

If you think your dog might have an eye condition, be sure to consult your vet.

Welcome to Part 2 of common eye conditions in canines.

6. Entropion 
   
   The term for inverted eyelids or eyelids that fold inwards is entropion. All or part of the eyelids can be affected in dogs that suffer from this painful genetic condition. The abnormality causes the eye’s surface to become irritated from hair or lashes scratching it. Later, damage can lead to corneal ulceration, perforation or the buildup of dark scar tissue. Watch out for excessive tearing and squinting.
   
   
7. Glaucoma
   
   Basically when eye fluids are unable to drain, eye pressure increases. Symptoms include cloudy corneas, dilated pupils, pain, increased tearing, redness and sometimes enlarged eyes. Untreated glaucoma usually results in impaired vision and eventually blindness.
   
   
8. Keratoconjunctivitis Sicca (KCS) or Dry Eye
   
   Adequate ‘tears’ are required to keep eyes lubricated. A deficiency in the aqueous tear film in dogs is responsible for dry eye (‘syndrome’), or keratoconjunctivitis sicca (KCS). The disorder is characterized by severely dry eye surfaces and dry eyelid linings. Symptoms vary, so any concerns should be reported to your vet.
   
   
9. Lens Luxation
   
   Lens luxation is the official term for a dislocated eye lens (the eye lens ‘leaves’ its allocated area). Dogs older than three and younger than 10 are typically affected. Breeds that are prone to lens luxation include border collies, cocker spaniels, German shepherds and terriers.
   
   
10. Progressive Retinal Atrophy (PRA)
    
    Progressive retinal atrophy (PRA) is another genetic disease that causes blindness and unfortunately it’s not easy to catch. Essentially the ‘film’ (retina) is wrinkled or scarred. The first warning sign: Night vision issues.

THAT’S IT FOR PART 2!

Find out more about the following conditions in Part 1:

• Cataracts
• Cherry Eye
• Blepharospasm
• Conjunctivitis (Pink Eye)
• Corneal and Scleral Wounds

Cats are weird, wonderful and rumoured to be wise… especially when you look in their eyes! But, how do they actually view the world around them? Well, science has come up with a few generally agreed upon facts to help us understand this interesting feline organ.

But, before we jump into feline eye facts, let’s take a look at eye anatomy first:

• Light enters the eye through a lens.
• Behind the lens of each eye there is a pupil (essentially a gateway to the retina).
• The retina sits at the back of the eye.
• Via the optic nerve, the retina transports images and light to the brain.
• The brain turns all this information into a visual we can understand.
• The retina has two types of receptors: ones that detect light (called rods)
   and ones that detect colour (called cones).

LOW LIGHT YES, PITCH-BLACK DARK NO

Somewhere along the line, many of us have heard that cats can see in total darkness. Unfortunately for them, this is not true. They do however only need one-sixth of the light we need to function. How is this possible? 

Reason number one: they have more rods (receptors that detect light). 

Reason number two: a certain tissue located at the back of the eyes allows light to reflect within the eye, enhancing sight. This same tissue is responsible for the slightly sinister shine that’s visible when we spot a cat in the dark

LIMITED ‘RAINBOW’ VISION

Distinguishing a variety of colours is not one of their strengths, however, they’re not totally colour blind. Compared to humans, they have fewer cones (receptors that detect colour) and these cones are less concentrated as well. Apart from not experiencing the intensity of hues, scientists reckon that greens and reds can’t be distinguished, while yellows and blues are clearer.

THE DEVIL IS NOT IN THE DETAIL

Although cats are not able to visualize the same amount of detail humans do, they’re not nearsighted (that is, they don’t have a vision problem related to lens shape defects). Instead, the amount of detail is affected by how the rods and cones work together. Compared to humans, objects such as leaves and text on a page are perceived differently. The fact that a cat’s lens shape remains unchanged in terms of close-up focus have many researchers convinced that cats are farsighted, with optimal vision up to 90 cm.

THE VALUE OF VERTICAL PUPILS

Pupils shaped like vertical slits are found in animals that are both diurnal and nocturnal.

The reason: This shape is able to facilitate faster pupil change. The reduced pupil size is also less affected by sudden light level changes as less light enters the lens.

WHAT IS ANTERIOR UVEITIS IN CATS?

Uveitis is one of the most common eye disorders in cats and can be extremely serious. Without medical attention, your cat’s eyesight is at great risk.

Uveitis is inflammation of the uvea, which is the dark tissue at the front of the eye that contains the blood vessels. This includes the iris (the coloured layer around the pupil), ciliary body, and choroid (see diagram below).

When the uvea becomes inflamed, the condition is referred to as anterior uveitis (inflammation of the front of the eye).