It, is the tendency for doll eyes to transform from their original brown color to violet/purple! (So not cute.) This happened to several of my artist dolls from the 1990s. The victims include three Original Lee Middleton dolls (actually sculpted by the late Lee Middleton) and two Hildegard Gunzel dolls.
To correct this flaw, I used an ultra fine point, brown Sharpie permanent maker to color over the outer surface of the eyes. Voila! Their original brown eyes are now brown again!
Lee Middleton Angel Kisses (Dark) Girl, 1992, with brown eyes that turned violet; her twin brother's eye color changed, too.
Lee Middleton Angel Kisses (Dark) Girl, 1992, after brown Sharpie treatment to eyes
Hildegard Gunzel's Ebony, 1991 (brown eyes turned violet)
Gunzel's Pablo, 1991, brown eyes turned violet
Ebony and Pablo after Sharpie treatment
Interestingly, the third doll in the 1991 Gunzel series, Blanca (shown above) has maintained her original brown eye color. It is possible that a different eye brand was used for Blanca.