How To Calculate Axial Length Using The Biometry Function; Phakic Eye; Dense Cataract Eye; Aphakic Eye - Tomey UD-800 Instruction Manual

4.2 How to calculate axial length using the biometry function

4.2.1 Phakic eye

4.2.2 Dense cataract eye

4.2.3 Aphakic eye

4.2.4 IOL eye

■ 4-16
The axial length measurement is obtained using the following
formulae.
<When using the average acoustic velocity>
L

V t

L
V
2
length
t
<When using the divisional acoustic velocity>

V t V
 
L acd acd
2
L
V
acd
V
Ins
V
vit
t
acd
t
Ins
t
vit
Take the axial length measurement in the same manner as
when using the average acoustic velocity for a phakic eye.
Take the axial length measurement in the same manner as when
using the average acoustic velocity for a phakic eye.
[Default setting for acoustic velocity at delivery (changeable)]
- IOL acoustic velocity (reference)
Acrylic
Silicone
PMMA
: Axial length measurement
: Average acoustic velocity for axial
: Measurement time
 
t V t

Ins Ins vit vit
2 2
: Axial length measurement
: Anterior chamber depth acoustic
velocity
: Crystal lens acoustic velocity
: Vitreous acoustic velocity
: Time for measuring anterior chamber
death
: Time for measuring crystal lens
: Time for measuring a vitreous
: 2,200m/s
: 1,049m/s
: 2,718m/s