KISA% is associated with-

Ans. is 'a' i.e., Keratoconus * The KISA index is used in cases of keratoconus and is derived using 4 indices:i) Central keratometry Kii) Inferior- Superior keratometry (I-S)iii) Astigmatism Index (AST)* It is calculated using videokeratograph device and it quantifies th degree of corneal astigmatism and the SRAX index which is expression of irregular astigmatism occurring in keratoconus.