Profiles
Reading, Focus, and Evening combine settings in one click. Save your own profiles, then use the menu bar to switch, pause, or return display tuning to neutral. Display controls and break timers work without camera access.
Your Display,
StrainFree
StrainFree uses novel strategies to tailor your display for eye comfort and well-being.
3 days to try it. $9.99 to make it yours.
Reading · softly warm
Tap − / +, drag a knob, or tap its edge. Arrow keys fine-tune · Shift for smaller steps
Illustrations only · these switches don’t change your display’s PWM or dithering.
Visual preview · changes this sample only
“I just watched this, just downloaded the free trial and in under a minute my screen is smooth and calming to look at!!!!”
Your screen
with comfort controls.
Upcoming interface
Select an area of the interface to explore its controls. This explains the app; it does not change your display.
Comfort strength
The Comfort strength knob changes how much of the chosen profile you apply. Start with a profile, make small adjustments, and save the combination that suits you.
Warmth
Warmth reduces blue and green in the display’s color balance, shifting cool whites toward amber. It changes how colors look; pause it when judging original colors.
Red Mode
Red Mode shifts the display toward red as you increase its strength. It changes the appearance of all colors.
Light & tone
Brightness dims the picture your Mac sends to the display. Soften dark areas lifts the darkest tones; soft whites lowers the brightest whites; soften highlights reduces bright middle tones. Your apps, documents and photos stay the same. Choose the light-and-tone display target below the faders.
Surface
Color calm adds a subtle neutral wash to vivid colors. Peripheral softening gently darkens the edges while leaving the center clearer. Screen uniformity is another surface adjustment. Surface controls affect all displays.
Paperlike
Paperlike lays a neutral wash over the built-in laptop display, muting color and contrast. Set the strength to keep it subtle or make the finish more noticeable. External displays and Sidecar can behave differently.
Texture & Monochrome
Fine grain adds optional fine, still dots to Paperlike. Monochrome gives a grayscale appearance across displays.
Breaks
Break reminders are optional: set the timing, pause them or take a break when you like. The new break screen starts with distance, then offers gentle blinks or a follow-the-dot activity. Blink awareness is separate and optional; its camera frames are processed locally without saving or uploading.
Settings
Choose app appearance and optional room-light adaptation, cursor assist, crisper text and battery-aware dimming. Sidecar comfort fallback appears when a Sidecar display is connected. Use these helpers only when they suit your setup.
Use supported GPU-side dithering controls and software dimming alongside your chosen hardware brightness. Support varies by Mac, macOS and display. Verification reports the software setting, not an optical measurement or proof that all flicker is gone. Panel dithering can remain.
There’s more to light than brightness and color.
How a screen dims its light.
Some screens lower brightness by pulsing their light very quickly. This is called PWM. StrainFree dims the picture separately from your Mac’s brightness setting.
Software dimming doesn’t switch those pulses off. The result depends on your display.
What this means on your Mac
Pulse-width modulation (PWM) controls brightness by switching light on and off rapidly. Shorter “on” periods produce less average light. A dim-looking screen is not necessarily a steady-light screen. [1]
Frequency, on-time (duty cycle), and modulation depth describe different aspects of this pattern. A light-output measurement is needed to assess a particular display. [3]
StrainFree lowers RGB output using the Mac’s display transfer curves, often called gamma controls. You set hardware brightness yourself; the app supplies software dimming.
Some displays use PWM at low brightness and DC dimming at higher settings, as EIZO documents. If your display has a less modulated range, software dimming can make its picture less bright. [2]
Higher hardware brightness is not universally better. StrainFree does not detect a safe threshold or directly disable PWM; behavior depends on the panel, its driver, and the content.
Illustrative LCD model
Changes this example only.
See the light pulses
Light output over time → Both traces use the same scale
Compare two ways to get a similarly dim picture.
Shorter pulses, with no software dimming.
Software dimming lowers the peaks, but leaves pulse timing and percentage modulation depth unchanged in this model. These values are not measurements or recommended settings.
Turn either knob to change this illustrative LCD model. Hardware brightness changes pulse on-time; software brightness lowers output. These controls do not adjust your actual display.
How your Mac fills in colors.
Your Mac can rapidly alternate a pixel between nearby colors to create an in-between shade. This is called temporal dithering. StrainFree can request that this Mac-generated effect be turned off.
Support varies. Your screen may still do its own dithering, and color gradients may look more stepped.
What this means on your Mac
Varying pixel values across successive frames creates intermediate shades that a display could not show in a single frame. This is a different mechanism from backlight PWM. [4]
StrainFree requests a change to GPU-side dithering and reads back the reported setting. Support depends on the Mac, macOS, and connected display. The panel can perform its own dithering. The Mac and the screen are separate parts of the process. [6]
Verification checks the reported software setting. It is not an optical measurement or proof that all flicker is gone.
Successive frames
Frame 1
+
Frame 2
→
Perceived shade
Alternating shades can create an in-between color.
Exaggerated illustration · no flashing · doesn’t change your display.
Research & sources
What the research tells us.
In a study of 20 people, researchers found that stronger visual-cortex responses to flickering light were associated with greater reported discomfort. The experiment used large, high-contrast fields at 1.625–30 Hz—not everyday laptop use or a test of high-frequency MacBook PWM. [5]
This supports taking flicker seriously, while keeping the claim specific. These sources explain the mechanisms; they do not establish a clinical benefit for StrainFree. Comfort also depends on the person, lighting, and viewing conditions.
To determine whether a particular setup reduces light modulation, the display needs an appropriate light-output measurement. A darker screenshot, a brightness percentage, or an app status badge cannot answer that by itself. [3]
Finding your settings.
- Start with your display. Check model-specific dimming information. There is no universal “PWM-free” brightness percentage.
- Adjust the two controls separately. If a higher hardware setting reduces modulation on your display, use software brightness to bring the picture back to a comfortable level.
- Refine the finish. Add warmth or soft whites to taste, explore supported dithering controls, and save the combination as a profile.
Sources
- Texas Instruments · Analog PWM Dimming in White-LED DriversHow on-time, frequency, and analog dimming differ. Application report, 2016.
- EIZO · Hybrid PWM and DC dimmingA manufacturer’s example of brightness-dependent dimming behavior; not evidence about every Mac display.
- CIE · Guidance on the Measurement of Temporal Light ModulationWaveforms, modulation depth, and measurement methods. Technical note 012:2021.
- Texas Instruments · Adaptive Hi-FRC DitheringSection 7.5.4 explains the temporal and spatial methods used to represent additional shades.
- Gentile & Aguirre · A neural correlate of visual discomfort from flickerOriginal study, Journal of Vision, 2020. Twenty participants; controlled visual stimuli.
- Stillcolor · Mac-generated ditheringOpen-source implementation for Apple silicon; distinguishes GPU/DCP dithering from a panel’s own processing.
Look away. Let your eyes rest.
20/20/20 vision
The app can remind you every 20 minutes to look about 20 feet away for 20 seconds. You can change the timing, pause reminders, or take a break whenever you like.
In the new break screen, you look away first. Afterward, you can choose gentle blinks or a short follow-the-dot activity—or simply return to work.
StrainFree
Apple silicon Mac · macOS 14 Sonoma or later.
Email required before download. Includes the new pixel interface.
Try StrainFree for 3 days.
Keep it for $9.99. One payment.
Apple Silicon · macOS 14 or later
Already tried it? Get a licenseNative wallpapers
Four ambient scenes included · Choose yours in Settings
Will it work on my Mac?
StrainFree requires an Apple Silicon Mac with macOS 14 Sonoma or later. Some display protections depend on the exact Mac, display, and macOS version. Paperlike is specific to the built-in laptop display.
Is the new interface available yet?
Yes. Version 1.0, build 126 includes the new pixel interface, comfort presets, and menu-bar controls. Get it from the download page, or check for updates in StrainFree.
Is there a subscription?
No. You get a 3-day local trial, followed by a one-time $9.99 license. See our pricing page for the current terms.
Does it need my camera?
Only optional blink awareness uses the camera. Frames are processed on your Mac and aren’t saved or uploaded. Display tuning and break reminders work without camera access.
Can I pause it or turn it off?
Yes. Pause appearance adjustments, turn off break reminders, or return your display tuning to neutral. You can quit and remove StrainFree like other Mac apps.
Is StrainFree a medical product?
No. StrainFree is a display comfort utility. It does not diagnose, treat, cure, or prevent eye conditions.
“StrainFree was built as a way for me to easily and intuitively adjust my screen’s settings to better suit my eyes.”The story behind StrainFree