4-3
■
4.1.2 SRK/T formula
1. Implanted IOL power (D) for emmentropization
()
YCL
Xna
P
emme
11
1000
−
=
2. Implanted IOL power (D) for ametropia
)
}
() ( ){}
rCYVREFYCL
rLXVREFXna
P
amet
⋅+⋅−−
⋅+⋅
=
1001.011
1001.01000
3. Predicted refractive power after surgery (D)
)
()()()
rCYVCLPrLXVna
CLYPXna
REF
iol
⋅+⋅−−⋅+⋅
−
=
111001.01
111000
Where:
X = na・r – L1 (nc – 1)
Y = na・r – C1 (nc – 1)
L1 : Visual axial length (mm)
= L + (0.65696-0.02029L)
L : Axial length (mm)
REF : Desired refractive power after surgery (D)
W : Calculated corneal diameter (mm)
= -5.41 + 0.58412LC + 0.098K
LC : Corrected axial length (mm)
L ≤ 24.2 → LC = L
L > 24.2 → LC = -3.446 + 1.716L - 0.0237L
2
C1 : Estimated anterior chamber depth after
surgery (mm)
= H + Ofst.
Ofst: Calculated distance from the iris surface to the
optical surface of the implanted IOL (including
corneal thickness) (mm)
= ACD const – 3.336
= (0.62467A – 68.747) - 3.336
H : Height of cornea dome (mm)
4/
22
Wrr −−=
A : A-Constant