What Causes Yellowing of the Sclera?
Disease description:
Recently, Grandma noticed that her black pupils (irises) appeared yellowish. What could cause yellowing of the iris?
Doctor's answer (1)
Dr. Wang Qingqiang
Yellowing of the black part of the eye (the iris) results from loss or abnormality of iris pigment. The central portion of the eyeball appears black because the brownish-black iris—located inside the eye—reflects light through the transparent corneal tissue. When the iris pigment changes to yellow, the “black” part of the eye appears yellow. Common causes include:
1. Pathological and non-pathological factors;
2. Aging—yellowing of the iris is common in elderly individuals;
3. Impaired hepatic metabolism, leading to accumulation of bilirubin in the skin’s stratum corneum and mucous membranes, which may also cause yellowing of the eyes;
4. Excessive consumption of foods rich in natural yellow pigments.
