ASK THE VET: Dog’s cloudy eyes could be normal aging, not cataracts

Editor's note: Dr. Lee Pickett is on vacation. This column first appeared in 2019.

Q: When Toto, my 10-year-old terrier, looks at me, his eyes appear cloudy. At last week's wellness exam, his veterinarian said his eyes are healthy and he has no cataracts or other problems. So why do his eyes reflect a cloudy white-blue-gray haze?

A: It sounds like Toto has a condition called nuclear sclerosis, which is not a disease but a normal consequence of aging that starts in dogs around age 7.

Nuclear sclerosis, also called lenticular sclerosis, is hardening (sclerosis) of the center (nucleus) of the lens (lenticular). Most dogs with nuclear sclerosis have normal vision, though some have a bit more trouble focusing on nearby objects because the hard lens doesn't change shape easily. Compare the condition to a middle-aged person who needs reading glasses.

In nuclear sclerosis, the lens remains transparent, so light travels through it to the retina to produce a normal image. Contrast this to a cataract, an opaque area of the lens that blocks light transmission to the retina. A cataract impairs vision, even causing blindness if it grows to encompass the entire lens.

In addition to nuclear sclerosis, senior dogs sometimes develop iris atrophy. The iris contains muscles that dilate the pupil in dim light and constrict it in bright light. If the iris atrophies with age, you may see tiny holes in it or an irregular border between the iris and the pupil. If Toto's irises have atrophied and he can't fully constrict his pupils, you may see him squint when he goes outdoors on sunny days.

Q: Every professional has a list of things they wish their clients knew. What's your Top 10 list for cat people?

A: Here's my Top 10, starting with a simple courtesy and ending with the most crucial:

No. 10: Please show up on time for your appointment. If you're late, you'll get less of your veterinarian's time or be asked to reschedule.

No. 9: Take your cat in a carrier, because without one, your cat could startle and jump from your arms. Ideally, your carrier should have top and side openings, and the top should be secured with large clips, not individual screws, so the hospital staff can easily remove it. Line the carrier with a towel, and spray the towel with the pheromone Feliway if your cat is nervous.

No. 8: Save money at the vet by preventing disease. Sterilize your cat to reduce the risk of mammary cancer, uterine infection and spraying. Vaccinate to save money on disease treatment. Prevent heartworms, intestinal worms, fleas and other parasites, rather than treat the problems they cause.

No. 7: It's not normal for a cat to regularly throw up hairballs. Research shows flavored petroleum jelly doesn't relieve hairballs or move hair along the gastrointestinal tract. Veterinarians have a saying: Hairballs aren't caused by a grease deficiency. See your vet to identify the cause of your cat's vomiting, and start effective therapy.

No. 6: We humans are told to drink plenty of water. But if your cat drinks excessively or the litter box contains more urine clumps than usual, your kitty may be developing diabetes, kidney disease or another problem. Make an appointment with your veterinarian.

No. 5: Dental care is important. Without it, bacteria in the gums travel to the kidneys, liver and heart, where they establish infections. Visit for a list of diets, treats and other products recommended by veterinary dentists to decrease plaque and tartar.

No. 4: Pet food bags advise you to feed more than is healthy, presumably because manufacturers' calculations are based on the needs of animals that haven't been sterilized and therefore have high metabolic rates. Don't let your cat get fat, because overweight cats are more likely to develop diabetes, arthritis and other disorders.

No. 3: Some plants, human foods and medications are toxic to cats. Examples are lilies, garlic and acetaminophen (Tylenol). When it doubt, ask your veterinarian.

No. 2: Environmental enrichment keeps your cat happy and actually decreases risk of disease. See

No. 1: Most important of all, a cat lasts a lifetime. Your kitty is not a disposable commodity to relinquish when you get bored. Cherish your cat forever, and your cat will return your love many times over.

Lee Pickett, VMD, practices companion animal medicine in North Carolina. Contact her at