Robert Chapin

Input fields on the WordPress admin screens have been nearly invisible since version 2.7. The problem was so severe that Matt suggested I make a plugin to override core CSS values for anyone who wanted more contrast. Following community feedback, I created this extra plugin specifically for high contrast.
This plugin adds Admin Color Scheme options that dramatically change the appearance of form fields, table rows, and background colors in the admin pages. It is not intended to follow the design principles of the built-in style sheets. If this is too much for your needs, then also consider my plugin with more subtle effects called <a href="https://wordpress.org/plugins/fix-admin-contrast/" rel="ugc">Fix Admin Contrast</a>

High Contrast Admin

Adds admin color schemes for the visually impaired.

mediarlos

Simple Accessibility Tools adds a configurable accessibility toolbar to public WordPress pages to improve reading comfort and navigation.
Included features:
<ul>
<li>Increase and decrease font size.</li>
<li>High contrast mode.</li>
<li>Visual filters: normal, sepia, inverted, negative, and grayscale.</li>
<li>Reading line that follows the cursor.</li>
<li>Increased text, word, and line spacing.</li>
<li>Readable font mode.</li>
<li>Link highlighting.</li>
<li>Pause animations.</li>
<li>Hide images, videos, and iframes.</li>
<li>Large cursor mode.</li>
<li>Reset visitor preferences.</li>
<li>Visitor preference persistence with localStorage.</li>
<li>Admin settings panel with checkboxes to enable or disabPlugin Checkle each option.</li>
<li>Language selector: Spanish, English, and French. English is the default language.</li>
<li>“Buy me a coffee” support link inside the admin settings panel.</li>
</ul>
When activated, the plugin inserts the toolbar on the frontend using <code>wp_footer</code>. Visible options and language are managed from Settings > Simple Accessibility Tools.

Simple Accessibility Tools

Adds a floating accessibility toolbar to the WordPress frontend.

High Contrast Admin vs Simple Accessibility Tools