There are multiple definitions:

1. slowly adapting nerve fiber type I(English)

   • CKO
   • Adaptation & plasticity, Nervous activity - (para)sympathetic

2. surface asymmetry index(English)

   • the difference between the keratometric power of opposite points on 128 meridians
   • KC
   • Ophthalmology
   • https://doi.org…ijo.IJO_2111_20

3. successful aging index(English)

   • Diet, Aging
   • https://doi.org…hem.2018.07.011