Tomey OA-2000 - Page 136

■ 4-10
K
pre
: Average corneal refractive power (D) before refractive
correction surgery
= (K1
pre
+ K2
pre
)/2
r
pre
: Radius of corneal curvature (mm) before refractive
correction surgery
= {(KI - 1) × 1000}/ K
pre
KI : Cornea equivalent refractive index
K
post
: Average corneal refractive power (D) after refractive
correction surgery
= (K1
post
+ K2
post
)/2
r
post
: Radius of corneal curvature (mm) after refractive
correction surgery
= {(KI - 1) × 1000}/ K
post
P : Implanted IOL power (D)
na : Aqueous humor and vitreous refractive index
= 1.336
nc : Corneal reflective index
= 1.333
REF : Target Ref. after surgery (D)
V : Vertex distance (mm)
= 12
4. Personal A-Constant


aacbbA 2/4
2

Where:
a : 0.62467
2
α
b : 0.62467 {2α(H – 72.083)} +β}
c : α(H – 72.083)
2
+β(H-72.083) + r
α : P (1 – nc) + 0.001P•AREF {V (nc – 1) – r}
β : P [na・r + L1 (nc – 1)
+ 0.001AREF {L1・r + V・L1 (1 – nc) - na・V・r }]
r : na [1000X – P・L1・r + AREF
{0.001P・V・L1・r – (V・X + L1・r)}]
AREF : Refractive power of eye after surgery (D)