Research overview: iris atrophy and pupil function in older cats

With age, the iris of a cat's eye can thin and degenerate, a condition called iris atrophy that may affect how the pupil responds to light. This overview surveys age-related iris atrophy in cats, in which the iris tissue weakens, sometimes causing the pupil to respond more sluggishly or unevenly to changes in illumination. Because the slit pupil's wide dynamic range is central to feline vision, changes in iris function can affect how well an older cat adjusts to varying light. The survey relates iris atrophy to the broader aging of the eye and to the monitoring of senior feline eyes. It discusses how the condition is usually identified during examination. Understanding iris atrophy connects the aging of the eye's structures to pupil function. It shows that even the iris, which gives the cat its distinctive responsive pupil, is subject to age-related change, adding to the suite of sensory shifts that accompany feline aging.