Blog · Digital Reading

Digital textbooks and dyslexia — font and spacing settings in VitalSource, Kindle, and Google Play Books

10 min read · August 15, 2026

Digital textbooks promised to fix a longstanding problem: heavy, expensive books you couldn't annotate the way you wanted. For dyslexic readers, they introduced a new one. Unlike a physical page you can overlay with a coloured sheet, or a website where a browser extension can rewrite every font, digital textbook platforms sit in a walled garden. Some let you change a lot. Some let you change almost nothing. Knowing which is which before you buy can save you a semester of frustration.

This guide covers the three platforms most dyslexic students are likely to encounter — VitalSource Bookshelf, Kindle Textbook Edition, and Google Play Books — along with a practical fallback for when the built-in tools run out.

Why font and spacing control matters more in textbooks than in fiction

Novels are mostly continuous prose. If you push through a difficult paragraph, the text flows on. Textbooks are structured differently: dense terminology, frequent changes in register (paragraph, caption, formula, table, footnote), and a layout designed to support scanning rather than linear reading. That structure creates additional demands for dyslexic readers.

Research consistently shows that increased line spacing and letter spacing reduce the crowding effects that slow dyslexic reading — but many textbook platforms apply tight academic spacing that you cannot change. Font choice matters too: a dyslexia-friendly font with distinct letterforms for b/d/p/q can meaningfully reduce decoding errors, but only if the platform lets you swap fonts at all.

The short version: the same text, in the same layout, in a font you can't change and at a line height you can't adjust, is harder for many dyslexic readers than the same text in a well-chosen font with breathing room. Platform choice is a practical accessibility decision, not just a preference.

VitalSource Bookshelf

VitalSource is the platform behind a large share of university textbook rentals and purchases, and its web reader (Bookshelf Online) runs in Chrome, Firefox, and Safari. The reading experience splits into two categories depending on how the publisher prepared the book.

Reflowable books — where the text flows like a website — expose a typography panel that lets you change font family, size, and line height. The default font options are modest (a handful of system fonts), but the spacing and size controls are genuine and apply immediately. If your textbook falls into this category, you have a reasonable baseline.

Fixed-layout books — which includes most science, mathematics, and design textbooks — are effectively page images. The text is rendered at a fixed size in a fixed position, and VitalSource's typography controls have no effect. You can zoom in, but you cannot reflow or reformat. This is the most common complaint from dyslexic students using VitalSource, and it is a real limitation with no in-platform solution.

One workaround worth knowing: Bookshelf Online is a web app, which means a browser extension can inject custom CSS. Extensions that override fonts on any website can sometimes reach the reflowable text layer in VitalSource — though fixed-layout pages remain locked. Testing before your purchase or rental period is worth the few minutes it takes.

Kindle Textbook Edition

Amazon's Kindle platform has invested more in accessibility than most of its competitors. The native Kindle app on iOS and Android offers OpenDyslexic as a font option alongside Bookerly, Georgia, and several others — a genuine win for dyslexic readers who can access titles through the mobile app. The full breakdown of Kindle's font options goes deeper on this, but the headline is: mobile gives you more control than browser.

The Kindle Cloud Reader — the browser-based version you'd use on a laptop or Chromebook — has a reduced set of fonts compared to the native app, and OpenDyslexic is not available there. You can still adjust font size, line spacing, and margins, which covers the most impactful spacing changes.

The limiting factor for textbooks specifically is the "enhanced typeset" format that many academic Kindle books use. Enhanced typeset books preserve the original publisher layout — page numbers, chapter layouts, figures in their original positions — which means font changes are partially or fully suppressed. If you're previewing a textbook on Amazon, the product page will usually indicate whether the Kindle edition supports font changes; look for "Text-to-Speech: Enabled" and "Word Wise: Not Enabled" as rough proxies for a reflowable layout. A title with "Enhanced typeset" listed is likely partially locked.

Google Play Books

For dyslexic readers, Google Play Books is often the most permissive platform — if the title you need is available there. The built-in font list includes OpenDyslexic and Lexend, both well-regarded for dyslexia, and the spacing controls (line height, margins) can be pushed quite far. The web reader in Chrome is clean and responds to system-level settings like high-contrast mode.

The limitation is catalogue depth. Google Play Books carries a smaller academic textbook selection than VitalSource or Kindle, so in practice many students don't have the option. When you do, it's worth checking here first.

The same PDF caveat applies: scanned textbooks uploaded as PDFs, or publisher-supplied PDFs embedded in the platform, don't reflow and don't respond to font settings. The Play Books PDF viewer lets you zoom, highlight, and annotate, but it cannot change the typeface of embedded text.

Comparison at a glance

When the platform won't cooperate — browser-level overrides

All three platforms have web readers that run in Chrome. That matters because it means a browser extension can reach the text layer in reflowable books, even when the platform's own font menu is limited.

A Chrome extension that swaps fonts globally across every site — like LexiFont — will detect the text inside VitalSource's or Kindle Cloud Reader's web reader and apply your chosen font, provided the book uses a reflowable layout rather than a fixed-image one. You can use this to bring in fonts the platform doesn't offer natively: Atkinson Hyperlegible, Lexend, or OpenDyslexic, depending on your preference. The research comparison of dyslexia fonts is worth reading before you decide which to set as your default.

If you're regularly fighting fixed-layout PDFs in a browser, the LexiFont Pro tier offers additional controls including custom line height and letter spacing overrides that apply to whatever text the browser can actually reach — useful for the portions of a mixed-layout book that do reflow.

How to evaluate a digital textbook before you buy

Most platforms offer a free preview of the first chapter or two. Before committing to a purchase or rental, run through this checklist:

Open the preview in the web reader (not just the PDF download). Go to the font or display settings panel and try to change the font and line height. If those controls are greyed out or absent, the book is fixed-layout and your accessibility options inside the platform are minimal. Check whether the text is selectable — if you can highlight a sentence, a browser extension can usually reach it. If clicking produces no selection, you're looking at an image layer.

If the book is fixed-layout and you have no alternative platform option, it's worth contacting your institution's disability services office. Many universities can provide reflowable EPUB versions of textbooks through accessibility licensing, even when the commercial platform only offers a fixed PDF. This route takes time but often yields a significantly more readable version of the same content.

The bigger picture — what platforms still get wrong

The inconsistency across platforms points to a broader problem: accessibility features in digital textbooks are treated as optional by most publishers. WCAG guidelines, which cover web accessibility including font control and contrast, are not consistently applied to e-reader formats. A student who can fully customise a website's typography with a browser extension may be completely unable to change anything in a textbook they paid a hundred euros for.

Progress is slow, but there are pressure points. Disability advocates have pushed for EPUB accessibility standards (EPUB Accessibility 1.1), and publishers who distribute through Apple Books and Google Play increasingly need to certify that their ebooks meet those standards — which includes basic font control for reflowable content. VitalSource and Kindle are less subject to this pressure, though Amazon has gradually expanded Kindle's accessibility features over the past few years.

In the meantime, understanding which platforms give you control — and having a browser-level fallback for when they don't — is the most practical approach available to dyslexic readers today. The broader toolkit for university students with dyslexia covers complementary tools that work alongside any textbook platform, including text-to-speech extensions and annotation tools designed for the way dyslexic readers move through academic material.

A practical setup in under ten minutes

If you're starting from scratch, here's what to do today. Install a font-override extension in Chrome and set your preferred dyslexia font — Lexend and Atkinson Hyperlegible are good starting points if you haven't tried them, and OpenDyslexic is worth a trial if letter confusion is your main challenge. Open your textbook's web reader and check whether the font change applies to the body text. If it does, you're done. If it doesn't, open the platform's own settings panel and push line spacing and font size to the comfortable limit. That combination — maximum in-platform spacing, browser-level font where it reaches — is the best you can get without switching formats entirely.

For background colour changes, most platforms offer at least sepia or night mode, which removes the harsh white background many readers find tiring. If the built-in options aren't quite right, a browser extension can usually override background colour on the web reader page as an additional layer.

Further reading

If you're working through related accessibility questions, these posts go deeper on specific aspects of the same problem:

• Kindle fonts for dyslexia — Bookerly, OpenDyslexic, and what each option actually changes
• Dyslexia-friendly PDF reading in Chrome — what actually helps
• Reading ebooks on a laptop with dyslexia — platform, app, and setting choices
• Dyslexia tools for university students — a practical toolkit