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Equation accessibility is important for several audiences including screen reader users, low vision users requiring magnification and users with reading differences who use text to speech.

As will be shown below, several options are available to create and support equation accessibility.

Avoid Image with ALT tag

Earilier guides (including this one) may have suggested using an image of an equation with an ALT tag. However, it was always problematic and there are better solutions available now.

For the record, the issue of using equations as images include:

Issues with Image ALT Text

  • Images may get fuzzy under magnification.
  • Screen reader options for complex equations are better with MathML in which they can elect to read parts of equation (e.g. the numerator of a fraction).

Example Matrix Image with Long Description Below

[image]

ALT: An image showing a matrix and a transposed matrix see details in the long desctription below.

The image shows two matrix tables separated by an = sign. The first is 2 rows by 3 columns and has a superscript T beside it. The next has the same numbers but rearranged into 3 rows by 2 columns. The tables are shown below:

Matrix Table Data
Matrix 1 (Superscript T)
R/C C1 C2 C3
R1 1 2 3
R2 0 −6 7

 

=Matrix 2
R/C C1 C2
R1 1 0
R2 2 −6
R3 3 7

MathML

Math ML is a text-based XML markup language designed for math equations. Browsers which support MathML are able to translate the XML into a formatted equation. Since MathML with MathJax can be rendered in many systems including HTML, Sites at Penn State, ANGEL and Drupal, it is considered the best choice in terms of accessibility.

See below for an example of an MathML Equation. Information about creating and viewing MathML is available on that page.

Sample MathML with MathJax Support


m = m 0 1 − v 2 c 2

 

View MathML Code

<math display="block" xmlns="http://www.w3.org/1998/Math/MathML">
<mrow>
  <mi>m</mi><mo>=</mo><mfrac>
<mrow>
  <msub>
    <mi>m</mi>
    <mn>0</mn>
  </msub>
</mrow>
<mrow>
<msqrt>
  <mrow>
    <mn>1</mn><mo>&#x2212;</mo>
<mfrac>
  <mrow>
  <msup>
    <mi>v</mi>
    <mn>2</mn>
  </msup>
</mrow>
<mrow>
  <msup>
    <mi>c</mi>
    <mn>2</mn>
  </msup>
</mrow>
</mfrac>
</mrow>
</msqrt>
</mrow>
</mfrac>
</mrow>
</math>

There are several options for creating MathML including Canvas, Microsoft Word and Sites at Penn State. See details below.

Caveats to MathML

MathML is an essential part of math accessibility, but there are situations when plain text may be better:

MathML Not Needed

  • Numbers (e.g. 12,234 or 12.56)
  • Numbers with currency symbols (e.g $12.99).
  • Just a letter variable (e.g. x).

Note: Some users have JAWS have requested to use MathML only for expressions with particularly complex layout.

Tools Supporting MathML

Technical Symbols in Unicode

In some cases, an instructor may wish to use Unicode text to insert a symbol into text as in the examples below:

Unicode Text Check

P ⊃ P ∨ Q (P implies P or Q)

In this case it is important to ensure that screen readers are configured to output these symbols. Some specifics are listed below:

Screen Reader Symbol Support

Caveats to Text Equations

Text equations can be useful for expressions which are one line and have no superscripts/subscripts or complex layouts.

MathML is especially recommended for:

  • superscripts and subscripts
  • complex fractions,
  • square roots,
  • matrix expressions,
  • integrals,
  • summations

and any expression with similar layout considerations.

LaTeX Considerations

LaTeX is a math markup language familiar to many in the science and math community, but unfortunately is not currently supported by most screenreader technlogy.

Nevertheless, many mathemeticians, including those with disabilities can use raw LaTeX code. Below are some considerations for how to leverage LaTeX

LaTeX Example

m=\frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}}

Displays As


m = m 0 1 − v 2 c 2

Never Accessible: PDF

A PDF file created from a .tex file is always inaccessible. If content is stored in a LaTeX .tex or R markdown file, utilities, such as Pandoc should be used to provide an accessible format.

Conversion to MathML

There are also many utilities which can convert LaTeX to MathML (and vice-versa). These tools include:

Equatio AT

Penn State has licensed access to the Equatio equation editor and digital math toolset for Penn State instructors, students and staff. Equatio includes the following tools which can be tested in the pilot

  • Read highlighted equation aloud
  • Convert embedded equation images to MathML or LaTeX
  • Speech recognition input

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