Size Progressions - Ametek Reichert ClearChart2 User Manual

Installation, Features, & Functions

Size Progressions

When multiple lines of descending size are in use, the line size display is that of the
smallest line. The standard progression has the following visual acuity sizes expressed
as Snellen fractions:
Snellen
20/10
20/15
20/20
20/25
20/30
20/40
20/50
20/60
20/70
20/80
20/100
20/200
20/400
Another line size progression available in ClearChart 2 is the LogMAR progression.
This progression has proved useful in prescribing low vision magnification aids and
permits a more precise method of scoring visual acuity.
Snellen
20/10
20/12.5
20/16
20/20
20/25
20/32
20/40
20/50
20/63
20/80
20/100
20/125
20/160
20/200
20/250
20/320
20/400
When the LogMAR progression is being used, the line size display shows the Snellen
value in the lower right-hand corner with the LogMAR line size next to it.
18
Snellen(metric)
6/3.0
6/4.5
6/6.0
6/7.5
6/9.0
6/12.0
6/15.0
6/18.0
6/21.0
6/24.0
6/30.0
6/60.0
6/120
Snellen(metric)
6/3.0
6/3.8
6/4.8
6/6.0
6/7.5
6/9.5
6/12
6/15
6/19
6/24
6/30
6/38
6/48
6/60
6/76
6/96
6/120
ClearChart 2 Digital Acuity System User's Guide 13760-101 Rev. H
(continued)
Snellen (decimal)
2.00
1.33
1.00
0.800
0.667
0.500
0.400
0.333
0.286
0.250
0.200
0.100
0.050
LogMAR
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3