11/7/2022 0 Comments Eye with no pupil![]() ![]() These disorders include cataracts, in which the lens gradually clouds up-often impenetrably-and prevents light from entering the eye glaucoma, a condition marked by excessive fluid pressure within the eyeball that can cause it to harden progressive retinal atrophy, in which the retinal tissue degenerates and loses its ability to function properly and a variety of tumors-either malignant or benign-that develop within the eye or adjacent to it. Thanks to the tapetum lucidum, a cat’s sensitivity to light is thought to be about six times greater than that of a human’s.Ĭats are subject to a host of diseases that can cause permanent damage to any or all of the eye’s components. This structure-the tapetum lucidum-reflects light not absorbed by the retina during its first passage through the eye, thus giving the light a second chance to be absorbed and transmitted to the brain. This extra eyelid helps keep the surface of a cat’s eyeball moist, protects it from being scratched by erratically growing hairs, and can help shield it during a scrap with a rival cat or other animal.Ĭats also have a specialized layer of tissue beneath the retina that reflects incoming light. ![]() Among these features is a third eyelid-or “haw”-a thin, pale membrane positioned at the inner corner of the eye, between the lower eyelid and the eyeball. While structurally similar in most respects to human eyes, feline eyes have acquired over thousands of years a number of distinctive features that improve its chances for survival as both predator and prey. Optic nerve, the conduit leading from the retina to the brain. Retina, a sensitive membrane that lines the interior surface of the eyeball, receives the focused light impulses that have entered through the lens, and sends them along to the brain, as visual information Lens, a transparent structure that adjusts its shape as needed to focus the light rays Iris, the round, pigmented membrane that surrounds the pupil and contracts or expands to regulate the amount of incoming light Pupil, the circular membrane in the center of the eye that permits the entry of light from the environment The major structural and functional components include:Ĭornea, the transparent outer covering of the eyeball ![]() Overall, feline eyes function in the same way that human eyes function and are made up of the same components. Kern urges owners to keep an eye out for any behavioral or physical indications that a cat is having a vision problem and to report any such signs to a veterinarian without delay. And most of them are middle-aged or elderly cats whose vision loss has been progressing for years."Īs is true for virtually all threats to feline health, the earlier a cat’s vision problem is diagnosed, the more effectively it can be treated-unless, of course, the animal’s blindness has progressed irreversibly by the time it is noticed. "Most of these animals have eye disease as a primary disorder-they have no other health problems. "We see cats that are either blind or going blind several times a week," says Thomas Kern, DVM, associate professor of ophthalmology at Cornell University’s College of Veterinary Medicine. Unfortunately, these finely-tuned feline eyes are vulnerable to injury and a wide variety of diseases that can dramatically impair a cat’s eyesight or, in some cases, render a cat partially or totally blind. In most cases, early diagnosis and treatment can keep a cat from losing its eyesight, but it's important to look for signs of trouble and ensure your cat gets regular check-ups.Ĭats have developed several unique vision features during their evolution that enable them to see clearly indoors and out. ![]()
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