Cornification index or eosinophilic index in the diagnosis of atrophic vaginitis indicates:

The degree of maturation of exfoliated vaginal epithelial cells, as revealed by stained vaginal smears, is an index of estrogenic activity. Among the various methods of assessing the smears, the following are most commonly used: the maturation index consists of a differential count of 3 types of squamous cells--parabasal cells, intermediate cells, and superficial cells, in that order--expressed as percentages (eg, 10/85/5); a greater percentage of parabasal cells reflects a greater degree of atrophy. The cornification count is the percentage of pre cornified and cornified cells among total squamous cells counted. This is actually a simplified maturation index, because this percentage is essentially the same as that of the superficial cells. Ref: Nathan L. (2013). Chapter 59. Menopause & Postmenopause. In A.H. DeCherney, L. Nathan, N. Laufer, A.S. Roman (Eds), CURRENT Diagnosis & Treatment: Obstetrics & Gynecology, 11e.