PROCESSED IMAGE


The image with overlying rings will 
be seen on the left side of the screen 
with the corneal curvature for each 
ring, simulated K’s, surface regularity 
index (SRI), surface asymmetry index 
(SAI), and potential visual acuity (PVA).

SAI usually has a value of less than 0.5 
for normal corneas.  If the cornea is 
distorted the SAI increases and may 
be greater than 5 for moderate 
keratoconus for example.

PVA is the estimate of what the visual 
acuity should be based on the distortion 
of the cornea.

The SRI is correlated to the potential visual acuity.