Cats are known for their keen eyesight and ability to see in low light. But can they see clear materials like glass? If you’ve ever seen a cat run headfirst into a glass door or window, you may have wondered about their ability to perceive transparent objects.
If you’re short on time, here’s a quick answer to your question: Yes, cats can see glass, but not as clearly as opaque objects. Their vision is specially adapted to detect movement, which makes stationary transparent objects harder for them to notice.
In this comprehensive article, we’ll take an in-depth look at feline vision, explaining everything from the anatomy of cats’ eyes to how their visual system works differently than human sight. We’ll discuss how cats perceive color, depth, and motion, and why clear materials can sometimes be puzzling.
Read on for a deep dive into the capabilities and limitations of cats’ remarkable eyesight!
The Anatomy of Feline Eyes
Size, Placement, and Field of View
Cats have relatively large eyes for their size. Their eyes make up about 1% of their total body weight, while human eyes only make up 0.0003%. The placement of their eyes also gives felines excellent peripheral vision.
Cats have a field of view covering 200 degrees horizontally – that’s an expansive panoramic view! For comparison, humans have a field of view of around 180 degrees.
Tapetum Lucidum Layer
The tapetum lucidum is a reflective layer in cats’ eyes that helps them see better at night by improving light sensitivity. When light enters a cat’s eye, the tapetum lucidum reflects it back through the retina for a second pass that gives their photoreceptors another chance to absorb the photons.
This allows cats to make the most of low lighting conditions and see up to 8 times better than humans can in the dark!
Rod-Dominated Retinas
There are two types of photoreceptors in eyes – rods that distinguish light/dark and motion, and cones that discern color and detail. A cat’s retina contains about 15-25 rods for every cone – that’s significantly more weight on the rod side.
As a result, felines have incredible night vision and motion detection abilities, but they “see color like a human who is red-green color blind”, according to studies from the Cummings School of Veterinary Medicine at Tufts University.
How Cats See Versus Humans
Advanced Motion Detection
Cats have a much wider field of vision than humans do. Their peripheral vision is about 285 degrees compared to humans’ 180 degrees. This allows cats to more easily detect movement around them, which was useful for their survival when hunting prey in the wild.
Cats also have a high flicker fusion rate, meaning they can see rapid changes in light. This helps them detect quick movements that humans would miss. According to the Cat Fanciers’ Association, the area of a cat’s retina devoted to sensing motion is roughly 5 times greater than that of humans.
Limited Color Vision
Humans are trichromats, meaning we have three types of color receptor cones that allow us to see the full spectrum of color. Cats, on the other hand, are dichromats with only two types of cones. This means they can’t distinguish between red, orange, and green hues.
Instead, cats see limited colors like blue, green, and yellow. Their world consists mainly of shades of gray. So don’t expect your cat to appreciate those colorful cat toys in quite the same way you do!
Poor Close-Up Vision
While cats have excellent distance vision, they can’t focus on objects within 20 inches of their face. This leaves them with a large blind spot for things that are very close to their eyes. As a result, cats will turn their heads slightly and look at nearby objects from the corner of their eyes.
Their close-up vision is so poor that an object needs to be around 10-20 times farther away from a cat as compared to a human for an equivalent level of clarity.
Enhanced Night Vision
Cats are crepuscular, meaning they are most active at dawn and dusk. As a result, their eyes have evolved to see well in low light conditions. Cats have a reflective layer called the tapetum lucidum behind their retinas that reflects light back through the retina, allowing photoreceptor cells a second chance to capture photons.
This boosts their ability to see in darkness by 3-6 times better than humans. The tradeoff is that cats lose some visual acuity in bright light since the second layer scatters the light a bit. Still, their enhanced night vision allows cats to hunt effectively at night.
Why Glass Appears Invisible to Cats
Lack of Movement and Scent
Glass is an invisible barrier to cats primarily because it lacks two key things that attract a cat’s attention – movement and scent. Cats have sharp vision attuned to detecting motion and their powerful sense of smell draws them to interesting aromas.
Still, transparent glass panes have neither, making them practically undetectable to felines.
Without motion or odor cues, glass might as well be an empty void to cats. This is why they can unwittingly leap at windows. To them, it’s just open space, not a solid pane. The apparent invisibility of motionless, scentless glass likely stems from cats’ hunting instincts.
Things that don’t move or smell like prey simply don’t register as obstacles in their visual field.
Reflective and Transparent Qualities
Another factor is the unique visual properties of glass. Its reflective yet see-through quality can create confusing optical illusions for cats. Outdoor images like trees or birds can be clearly visible through glass, so a cat may perceive an unblocked path ahead.
Yet simultaneously, indoor reflections bounce back at them. This contradictory sensory input likely contributes to cats missing the presence of glass barriers.
Research suggests cats can perceive images reflecting back at them to some degree. But these backwards images probably remain secondary to what cats see looking forward through the transparency. So the reflective quality of glass likely adds distraction, not clarity.
This may explain why cats struggle to understand glass as a solid obstacle until they have direct physical contact.
Small Visual Focus Area
Finally, experts believe the limited focus area of cats’ vision also causes them to overlook glass. While humans have wide-angle vision with sharp focus across a broad visual field, cats see sharply only in a small area they concentrate on. Their peripheral vision is far more blurred.
Consequently, transparent glass may simply fall outside a cat’s focal view as it gazes intently at something ahead. The cat just doesn’t see the clear barrier because its vision prioritizes what’s directly in front of it, not transparent objects on the periphery.
So glass can disappear from feline sight by virtue of where cats optically focus their eyes.
Training Cats to Notice Glass
Glass surfaces like windows or doors can be nearly invisible barriers to cats, leading to potential injuries from running into or jumping at transparent panels. Luckily, there are methods owners can employ to make glass more noticeable to felines.
Apply Stickers for Visibility
Placing stickers, tape, or decals on glass doors and windows at cat eye-level creates patterns that act as visual cues. Researchers have found that vertical stripes spaced 4 inches apart are ideal for cats to perceive depth and avoid collisions (AVMA).
Dots, shapes, and smears also effectively indicate the presence of transparent barriers.
Block Off Reflections
Cats often mistake the outdoor spaces seen in reflections for reachable areas and leap at windows or sliding doors. Preventing images of plants, birds, and other animals from shining through glass removes this temptation.
Methods include shutting curtains and blinds, placing frosted cling film on window surfaces, or keeping outdoor distractions like bird feeders out of sight from home windows.
Create Motion Near Glass
Hanging mobiles, wind chimes, bead curtains, or other movable objects close to see-through panes signals their presence to pets. Cats associate the proximity of flowing, noise-making decorations with an obstacle to avoid.
Positioning fans or sprinklers to blow air currents toward transparent openings also warns felines of an upcoming partition between indoor and outdoor.
With a blend of visual markers, reflection blockers, and kinetic alerts near glass fixtures, cat owners can guide pets to identify and evade risky transparent hazards.
Preventing Accidents Around Glass
Use Opaque Window Treatments
Installing opaque window treatments like curtains, blinds, or frosted window film can help prevent accidents around glass. Cats may not realize a window is there if they can’t see through it clearly. Opaque window coverings signal it is a solid barrier rather than an opening they can jump through.
According to the American Humane Society’s website (https://www.americanhumane.org/), nearly 200 cats fall from high-rise apartment buildings each year, with most falls occurring through open windows. Opaque treatments can block this view and temptation for curious cats.
Install Cat Shelves Near Windows
Giving cats an approved viewing spot near windows is another great accident prevention strategy. Installing a cat tree, shelf, or perch allows them to observe the outside world they long to explore without ending in disaster.
Opt for wider, more stable surfaces as narrow perches still carry some risk of falling. Locate these cat viewing stations a safe distance from the window pane itself. Cats should be able to glimpse outside while minimizing contact with the glass they may not see.
This satisfies their curiosity in a secure way.
Keep Glass Doors Ajar
Indoor and outdoor cats alike can crash into sliding glass doors by mistake. According to the Cat Friendly Homes Program from the American Association of Feline Practitioners (https://catfriendly.com/), this happens most frequently when a glass door is closed.
Keeping doors slightly open removes the transparent barrier cats don’t understand is there. You can also apply special decals with patterns or images at cat eye level. These markings help signal it is not a clear passage even when closed.
For further prevention, install a screen door in front of the glass one so your cat never directly contacts its surface. This adds visible material and also decreases any chance of it unexpectedly swinging open.
Conclusion
While cats can technically see transparent materials like glass, their vision is specially tuned for detecting movement and is not as adept at discerning stationary objects. Glass doors, windows, and tabletops can easily blend into the surroundings for cats.
With some training and prevention methods, however, cat owners can reduce the chances of their feline friends having dangerous or confusing encounters with household glass. Understanding how cats’ eyes differ from human vision helps explain why they find clear surfaces so perplexing at times.
