By: Carmen Willings
teachingvisuallyimpaired.com
​Updated October 23, 2017

I use this environmental print comparison regularly to help team members understand the comparison between the acuity a student is able to visually access and how it relates to font sizes. Keep in mind that it is important to use the lowest font size a student is able to easily, accurately, and fluidly read for longer passages. Although a student may have a threshold for a smaller font, if they cannot read it with accuracy and fluency, it will not be an efficient font size for sustained reading.

Near Vision Snellen Test Chart

The following is a list of environmental print that correlates to the acuity on a Near Vision Snellen Test Chart.
Jaeger
M
Acuity
Print Size Comparison
Example
Value
.4
20/20
 3 pt font
medicine bottle labels
J1
.5
20/25
4 pt font
mail order catalogs
J2
.6
20/30
5 pt font
small print Bible; footnotes
J3
.8
20/40
6 pt font
want ads; telephone directory
J5
1.0
20/50
8 pt font
small column newsprint
J7
1.2
20/60
10 pt font
paperback books; newsprint
J10
1.3
20/65
12 pt font
Grade 4-7 children's books
-
1.6
20/80
14 pt font
Grade 1-3 children's books
-
2.0
20/100
16 pt font
computer display type
-
2.15
20/108
18 pt font
Pre-K/K Children's books
J12
2.5
20/125
20 pt font
Books for ages 7-8
J14
3.0
20/150
24 pt font
Large Print Books
J15
4.0
20/200
33 pt font
Sub-headlines; children's books
J16
8.0
20/400
66 pt font
Newspaper headlines
Information in the above chart was taken from the "Near Vision Test Chart" by the Low Vision Clinic, N.C. Memorial Hospital Dept. of Ophthalmology, University of North Carolina School of Medicine, Chapel Hill, NC.

Functional Distance Acuity Approximations

The following is is a list of Functional Distance Acuity Approximations at a distance of 20 feet.
Gross Sizes (Observable overall size of an item)
Snellen Equivalent
Minimum Sizes (separation, detail sizes)
Snellen Equivalent
3/8"
20/20
1/16"
20/20
7/16"
20/25
.
.
1/2"
20/30
1/8"
20/30
3/4"
20/40
3/16"
20/40
1"
20/60
1/4"
20/60
1 1/2"
20/80
5/16"
20/80
1 3/4"
20/100
7/16"
20/100
2"
20/120
1/2"
20/120
2 7/16"
20/140
9/16"
20/140
2 3/4"
20/160
11/16"
20/160
3 1/4"
20/180
.
.
3 1/2"
20/200
13/16"
20/200
4 1/4"
20/225
.
.
5 1/4"
20/300
5/16"
20/300
6 3/4"
20/350
1"
20/350
7 1/8"
20/400
1 3/16"
20/400
10 1/2"
20/600
1 1/2"
20/600
12"
20/700
1 5/8"
20/700

Approximate Functional Vision Acuity

An approximation of functional visual acuity can be determined for students that are non-verbal or otherwise unable to perform for standard acuity assessment by comparing the size of the object the student can identify to the distance from the student. Although this can't be used as an exact measurement, it can provide you with an idea of the student's acuity.

Distance from the student:

Size of Object
2 feet
4 feet
6 feet
8 feet
20 feet
1/4"
20/200
20/100
20/67
20/50
20/20
1/2"
20/400
20/200
20/133
20/100
20/40
3/4"
20/600
20/300
20/200
20/150
20/60
1"
20/800
20/400
20/267
20/200
20/80
Topor, I. (2004). Approximate functional visual acuity for different sizes of objects and distances. Chapel Hill, NC: Early Intervention Training Center for Infants and Toddlers With Visual Impairments, FPG Child Development Institute, UNC-CH. Visual Conditions Module 06/06/04 S4 Handout H

Conducting a FVLMA On-Demand Webinar

Cover slide of Strategies and Tips for Conducting the FVLMA with the letters FVLMA in different colors and each wearing glasses
This presentation provides a walk-through of the process and steps of conducting a Functional Vision Evaluation and Learning/Reading Media Assessment. Key points include interpreting the eye report, materials to use in the assessment, conducting interviews and observations as well as strategies for direct assessment and writing a professional and thorough report that is informative to all audiences.  Next steps are also covered including the importance of a low vision assessment, determining the need for additional assistive technology and implications for service.  ​

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Picture of Typometer Kostenlos
Recently, Carson Cochran, program manager at GIMC, shared a typometer pdf that was printed on clear acetate with me. By printing it on clear acetate, you can place the typometer over print to determine the font size. You can find a number of these available on Pinterest or by doing a Google search. Pictured is the Typometer that Carson provided me. What a great tool! 
Picture of C-Thru Flexible Typesetter Ruler
​A typesetter ruler, like this C-Thru Flexible Typesetter’s Ruler, is made of clear plastic and has leading, type size, point rule, pica, point and inch scales. It will include font samples and rules of different sizes and more. Place it over your printed piece and match up the text in your sample with those printed on the ruler in order to get an estimate of the font size and line spacing and size of any rules in the design.  APH's Newt kit includes this typesetter ruler!