NACOR NEED TO KNOW
level of significance for FST/BST/BiT - ANSFST: below 1
BST: min. 2, max. 3
BiT: over 3
use for specular reflection - ANSendothelium mosaic, tear film
steps for a sph/asph GP - ANS1. vertex rx
2. RA= TA-CA
3. lens power - calc. tear lens based on nomogram (steeper/flatter)
4. calc. BC based on nomogram (using 337.5/mm)
5. choose diameter using nomogram
use for optic section - ANS-corneal thickness
-stroma
-aqueous flare
-depth f opacities
-scars
-foreign bodies
K's 45.00 to 48.75 needs BC of - ANS8.5 to 8.2
*higher the K's the lower the BC
formula for vertex rx - ANS*for rx over 4.00 D
Fc = F(rx) / 1-d (Frx)
*d = vertex distance in m - usually .012m
initial fit protocol - ANS1. history
2. prefit exam - VA
3. measurement: rx, k's, PF, HVID, TBUT, tarsal
4. determine best lens
over k too flat - ANSclear then blurry after blink
formula for minimum blank size - ANSeffective diameter (ED) + (2 x decentration)
*decentration referring to horizontal decentration
over k too steep - ANSblurry then clear after blink
level of significance for FST/BST/BiT - ANSFST: below 1
BST: min. 2, max. 3
BiT: over 3
use for specular reflection - ANSendothelium mosaic, tear film
steps for a sph/asph GP - ANS1. vertex rx
2. RA= TA-CA
3. lens power - calc. tear lens based on nomogram (steeper/flatter)
4. calc. BC based on nomogram (using 337.5/mm)
5. choose diameter using nomogram
use for optic section - ANS-corneal thickness
-stroma
-aqueous flare
-depth f opacities
-scars
-foreign bodies
K's 45.00 to 48.75 needs BC of - ANS8.5 to 8.2
*higher the K's the lower the BC
formula for vertex rx - ANS*for rx over 4.00 D
Fc = F(rx) / 1-d (Frx)
*d = vertex distance in m - usually .012m
initial fit protocol - ANS1. history
2. prefit exam - VA
3. measurement: rx, k's, PF, HVID, TBUT, tarsal
4. determine best lens
over k too flat - ANSclear then blurry after blink
formula for minimum blank size - ANSeffective diameter (ED) + (2 x decentration)
*decentration referring to horizontal decentration
over k too steep - ANSblurry then clear after blink
