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About this tool
Dim everything except the line you are reading to hold your focus.
A focus reading mask shows one line of text at full contrast and dims every other line, so your eye has a single place to land. This one splits whatever you paste on its line breaks — one row per line — renders the active row bold on a filled background and drops the rest to 40% opacity, and moves the highlight with Previous line and Next line buttons while a counter reads Line 3 of 12. It is a reading aid for anyone who loses their place mid-paragraph, not a diagnostic or a medical device.
Open Focus Reading Mask on AltFTool — it loads instantly in your browser.
Paste or edit your text in the 'Text, one focus line per row' box — each newline becomes one focus row.
Step through with the 'Previous line' and 'Next line' buttons while the counter reads 'Line X of Y'.
Read the active line highlighted on a filled background at full contrast while every other line stays visible but faded to 40% opacity.
Each newline becomes one focus row, so you control exactly how much text sits inside a single highlight.
Surrounding lines stay on screen at reduced opacity, so you keep the context and can still see what comes next.
Previous and Next are real buttons that take keyboard focus, so stepping through does not depend on holding a mouse steady.
Break the text where you want the mask to stop — the highlight is exactly one line of your input, split on newlines. Paste a paragraph as a single line and the whole paragraph lights up; press Enter after each sentence or clause and the mask steps through them one at a time.
Faded. Non-active rows render at 40% opacity in the muted text colour, so they remain readable if you glance at them. Nothing is removed from the page, which means you can still scan ahead or check the line you just left.
No. The text lives in the page's own state while you use it and is never sent to a server, so private drafts, medical notes or unpublished scripts stay on your machine.
Line masking is a commonly used reading support, and many people find that isolating one line reduces the skipping and re-reading that comes with tracking difficulty. It is an informational aid only — it does not assess or diagnose anything, so speak to a specialist teacher, optometrist or clinician about a formal assessment.