Tomey UD-600, Operator'S Manual

Page: 206 / 262

4-14
4.4 Axial length calculation of Biometry
4.4.1 Normal
Axial length is calculated by the following formula.
<Calculation with mean velocity>
L: Axial length
V: Average sound velocity
t: Time
<Calculation with sectional velocity>
L: Axial length
V
acd
: ACD ultrasound velocity
V
lns
: Lens ultrasound velocity
V
vit
: Vitreous ultrasound velocity
t
acd
: ACD measurement time
t
lns
: Lens measurement time
t
vit
: Vitreous measurement time
V · t
L = ———
2
V
acd
·
t
acd
V
lns
·
t
lns
V
vit
·
t
vit
L = ————— + ————— + ————
2 2 2
4.4 Axial length calculation of Biometry