4-4
4.1.3 Holladay
a. IOL power (D)
P =
1000na {X - 0.001REF (VxX + L2xr)
(L2 - C2 - SF) [Y - 0.001REF {V
x
Y+ r (C2 + SF)
b. Desired postoperative refraction (D)
P
emme =
1000na x X - P x Q x Y
na (V
x
X + L2
x
r) - 0.001P
x
Q {V
x
Y + r (C2 + SF)}
Where:
X: naxr - L2 (nc - 1)
Y: naxr - (nc - 1) (C2 + SF)
Q: L2 - C2 - SF
na: Refractive index of aqueous and vitreous = 1.336
nc: Refractive index of cornea = 4.0/3.0
L: Measured axial length (mm)
r: Average corneal radius of curvature (mm) = 337.5/K
K: Average corneal refractive power = (K1 + K2)/2 (D)
SF: Surgeon factor
(Distance between iris surface and optical center of
IOL) (mm)
REF: Desired postoperative refraction
V: Vertex distance (mm) = 12
P: Power of IOL implant (D)
L2: Modified axial length (mm) = L + 0.2
C2: Anatomical anterior chamber depth (mm) (distance
between corneal apex and iris surface) (mm)
= 0.56 + Rag - Rag
2
- AG
2
/4
if r < 7 mm, then Rag = 7 mm
if r 7 mm, then Rag = r
AG = 12.5L/23.45 (if AG > 13.5 mm, then AG = 13.5
mm)
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