Tomey UD-800 User Manual

4-15 ■
K
pre
: Average corneal refractive power (D) before refractive
correction surgery
= (K1 + K2)/2
r
pre
: Average 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
= (K1post + K2post)/2
r
post
: Average 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) + γ
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 }]
γ : na [1000X – P•L1•r + AREF
{0.001P•V•L1•r – (V•X + L1•r)}]
AREF : Refractive power of eye after surgery (D)

Tomey UD-800 Specifications

General

Brand	Tomey
Model	UD-800
Category	Measuring Instruments
Language	English