Tomey AL-100 User Manual

4-12
4.2 Axial length calculation with biometry
4.2.1 Normal
Axial length is calculated using the following formula:
L =
V
x
t
2
Where:
L: Axial length
V: Average ultrasound velocity
t: Time
4.2.2 Dense Cataract
Axial length is calculated using the same formula as for the
normal lens.
4.2.3 Aphakic
Axial length is calculated using the same formula as for the
normal lens.
4.2.4 Pseudophakic (1~ 3)
Ultrasound velocity may vary between materials and
manufacturers and depending on temperature.
Axial length is calculated using the following formula:
Lp =
V
acd x tacd
+ Th +
Vvit x tvit
2 2
Where:
Lp: Axial length (mm)
Th: Central thickness of IOL (might be changed by user)
V
acd: Anterior depth sound Velocity
V
vit: Vitreous sound Velocity
tacd: Measuring Time for anterior drpth
tvit: Measuring Time for vitreous
Materials Ultrasound velocity in IOL
Pseudophakic 1 PMMA 2718m/s
Pseudophakic 2 Silicon 1049m/s
Pseudophakic 3 Acrylic 2200m/s

Tomey AL-100 Specifications

General

Brand	Tomey
Model	AL-100
Category	Measuring Instruments
Language	English