We don’t really know what our cat companion sees in terms of sharpness of image unlike for other humans for whom we can assume that their eyesight is not dissimilar to ours. A cat can’t undergo an eyesight test! We can’t ask our cat if they have vision problems and so on. I sense that there is more to know about domestic cat vision. And they can’t or don’t wear glasses or have corrective surgery for practical reasons. So all domestic, stray and feral cats have to accept the eyesight that they are born with uncomplainingly. Compared to humans that’s pretty tough.
For humans, 60% to 65% of the global population require some form of vision correction, which includes glasses, contact lenses, or refractive surgery. Among these, approximately 50% to 60% use glasses as their primary form of vision correction. Can we assume that around 60% of domestic cats require glasses but are not given them? 🙄😱
It would be nice to be in the head of a cat and see what they see. Common sense dictates that there will be variation in the quality of eyesight between cats just like humans.
Their compensatory abilities will hide poor eyesight as we know that even blind cats get around their hime competantly provided the furniture is not moved. For humans eyesight is their most important sense. For cats it is probably fair to say that it is not. There is a greater equality between a cat’s senses: hearing, smell and eyesight; each one supporting the other to create a high-quality whole.
Note: you can expand the infographic and see it full-size by clicking on the double-sided arrow bottom-right.
Here is a little more on this topic to expand what is said in the infographic which has to be very succinct.
Question: Do cats’ eyes create images as sharp as human eyes?
Cats’ eyes don’t create images as sharp as human eyes under normal daylight conditions. Here’s why:
1. Structure of the Retina
- Photoreceptor Density: Humans have a high density of cone cells in the central retina (the fovea), which is specialized for sharp color vision. Cats lack a true fovea and have fewer cone cells, so their vision isn’t as sharp in terms of detail.
- Rods vs. Cones: Cats have more rod cells than cone cells, which makes them excellent at detecting motion and seeing in low light but less capable of producing sharp, detailed images in bright light.
2. Light Sensitivity
- Cats’ eyes are highly adapted for night vision, with features like the tapetum lucidum (a reflective layer behind the retina) that enhances their ability to see in the dark. This reflective layer can scatter light slightly, which may reduce image sharpness compared to human eyes.
3. Visual Acuity
- Humans typically have a visual acuity of about 20/20, meaning we can see objects clearly at 20 feet that most people can see at the same distance. Cats’ visual acuity is estimated to be around 20/100 to 20/200, meaning they see at 20 feet what a human with normal vision can see clearly at 100–200 feet.
Summary
While cats excel in low-light conditions and detecting motion, their eyes don’t produce images as sharp as human eyes, particularly in daylight or when observing fine details. Their visual system is optimized for survival as predators in low-light environments rather than for sharp visual detail.
Question: Can cats suffer from near and far sightedness?
Yes, cats can suffer from vision problems akin to nearsightedness (myopia) or farsightedness (hyperopia), though these conditions are less studied in cats than in humans. Here’s what we know:
1. Nearsightedness (Myopia)
- Definition: Myopia occurs when the eye is shaped so that light focuses in front of the retina, causing distant objects to appear blurry.
- In Cats: Some cats may naturally have a predisposition to myopia, especially if their eyes are slightly misshapen or if there are developmental issues. Cats bred in captivity or with genetic predispositions might be more prone to this condition.
2. Farsightedness (Hyperopia)
- Definition: Hyperopia occurs when the eye is shaped so that light focuses behind the retina, causing nearby objects to appear blurry.
- In Cats: Farsightedness might occur in some cats, though this is less commonly reported. Older cats could also experience changes in their vision due to age-related issues like lens stiffness, potentially leading to hyperopia-like symptoms.
3. Diagnosis in Cats
- Veterinarians can assess a cat’s vision, but it’s not as simple as giving them an eye chart test! Instead, a vet might use tools like retinoscopy (shining a light into the eye to assess how it reflects off the retina) to evaluate vision clarity.
- Behavioral cues like difficulty judging distances, bumping into objects, or hesitating to jump may indicate vision problems.
4. Corrective Measures
- Unlike humans, corrective lenses or glasses aren’t typically used for cats. However, if a cat has vision issues that significantly affect its quality of life, addressing underlying causes (like injury or disease) can help.
Summary
Cats can experience vision abnormalities such as nearsightedness or farsightedness, but these conditions are harder to diagnose and generally less understood compared to humans. Their vision is primarily adapted for survival, and moderate vision impairments may not hinder them significantly.
Question: Why don’t we have glasses for cats?
Glasses for cats aren’t common because of several practical and biological reasons:
1. Cats’ Visual Needs Are Different
- Cats rely less on sharp, detailed vision and more on their other senses, like smell, hearing, and their ability to detect movement. Their vision is optimized for low light and hunting rather than reading or recognizing fine details.
- Vision impairments like nearsightedness or farsightedness might not significantly impact their ability to navigate the world as predators and companions.
2. Behavioral Challenges
- Cats are not likely to tolerate glasses. They are highly tactile animals and may find wearing glasses uncomfortable or annoying, leading them to paw at or shake off any eyewear.
- Securing glasses on a cat’s face without causing distress or hindering movement would be very difficult.
3. Alternative Adaptations
- Cats with poor vision can often adapt well by relying more heavily on their other senses, like their acute hearing and smell. Whiskers also help them navigate tight spaces by sensing their environment.
4. Veterinary Focus
- When cats have significant vision problems, these are often caused by underlying health issues like cataracts, retinal degeneration, or infections. Veterinary treatment focuses on addressing these root causes, rather than correcting vision with devices like glasses.
5. Glasses Aren’t Necessary for Cats
- Humans use glasses primarily because we rely heavily on our vision for detailed tasks like reading and driving. Cats don’t need detailed vision to perform their daily activities like hunting, eating, or exploring their environment.
Summary
Glasses for cats would be impractical and unnecessary, given their reliance on senses other than vision and their ability to adapt to mild visual impairments. Instead, veterinary care focuses on treating underlying conditions that affect their eyes.
