Comparison

Visual Vertical vs HemiStim

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Visual Vertical

This medical app offers a quick, accurate, and low-cost method for measuring subjective visual vertical. It's designed for neurologists and vestibular rehabilitation specialists to test patients, especially for brainstem lesions and otolithic function, using just an iPhone or iPad.

Highlights
  • Measure subjective visual vertical
  • Accurate and low-cost testing
  • Suitable for neurology and vestibular rehab
  • Tests for brainstem lesions
  • Evaluates otolithic function
  • Multiple readings and averaged results
  • Single, one-off readings
Features
Read full description

Visual Vertical makes high-grade subjective visual vertical (SVV) testing accessible to every practitioner — no expensive equipment required. SVV testing is a sensitive, validated measure for brainstem lesions and otolithic dysfunction, widely used in neurology and vestibular rehabilitation. Until now, accurate testing required bulky, costly apparatus. Visual Vertical changes that: all you need is your iPhone, a bucket, and a small piece of Blu Tack. How it works Mount your iPhone inside the bottom of a bucket using Blu Tack. The patient holds the bucket to their face and adjusts a line on screen until it appears vertical to them. The app records the deviation and calculates your result — accurate readings in minutes, at a fraction of the traditional cost. What you can measure - Left eye, right eye, or both eyes open - Single readings or full sequences across all conditions - One or three readings per condition, with automatic averaging Clean, minimal results screens make it easy to record and communicate findings.

About

HemiStim

This app offers visual stimulation for specific brain lobes, aiding in hemispheric connectivity. It utilizes color patterns and eye-tracking exercises for targeted left or right brain stimulation, controllable via simple taps and swipes. Therapy sessions are automatically tracked and can be emailed to clinicians.

Highlights
  • Visual stimulation of frontal, parietal, occipital, temporal lobes
  • Hemispheric brain stimulation
  • Color pattern selection
  • Eye tracking for saccadic and pursuit movements
  • Adjustable blink rate and timer
  • Automatic therapy session tracking
  • Clinician-patient email communication
Features
Read full description

Hemistim can be used as a visual stimulation of areas of the frontal, parietal, occipital, and temporal lobes hemispherically. It is a specific brain stimulation which is rarely used in conjunction with other treatments but can be used as a portion of a home-based program or an office-based program. Such usage may lead to improved hemispheric connectivity specific, targeted areas of the brain and its connections to the parietal/temporal or frontal cortices. Hemistim provides a visual stimulation through utilizing color patterns and eye tracking that can be used for specific left or right visual exercise. The stimulus is recognized and  interpreted by the contralateral (opposite) occipital lobe. Pursuit and saccadic eye movements are created by targeting on the moving object. Pursuit away from and saccade towards the alternating squares are initiated by the ipsilateral (same side) parietal and frontal cortex, respectively.  This gives the doctor the ability to work the frontal, parietal, occipital, and temporal lobes hemispherically.  HemStim is easy to use. Swipe left or right to select a different colored pattern. Multiple patterns are available. Tap a pattern to make it begin blinking. The pattern will blink until the timer stops it. Double tapping the pattern will also make it stop. The blink rate and timer can be changed using the sliders. Target motion is controlled by the tapping the small target to the right of the speed control. Choose among no motion, saccade, and pursuit by successive taps on the small target. Exterior motion is indicated by purple arrows on the target and interior motion by white arrows. The new Saccades screen only displays target motion. Drag the purple target with one finger to set the direction and length of its motion. Tap the screen once simultaneously with two fingers to switch between saccades, a dashed line, and pursuits, a solid line. Tap the screen once with one finger to start the saccades or pursuits. Double tap the screen with one finger to stop the target motion. HemiStim automatically tracks therapy sessions, recording all pertinent information about each one. Maintain close communication between clinician and patient via email.

Screenshots

Visual Vertical4 screens
HemiStim3 screens

Verdict

The call

The clearest difference is review sentiment: Visual Vertical at 100% against HemiStim's 38%. HemiStim's advantage is rating (2.4 vs 2.0) and update cadence (every 8 months vs every 38 months). On ratings volume, ads, in-app purchases and monetization model there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Visual Vertical costs $11.99 and HemiStim $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

HemiStim holds the better App Store score, 2.4 against 2.0. Both are backed by a comparable volume of ratings — 5 and 5 respectively. Written reviews complicate that: 100% of Visual Vertical's written reviews are positive against 38% of HemiStim's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Visual Vertical ships an update every 38 months, HemiStim every 8 months. The most recent releases landed on September 24, 2026 and September 14, 2026 respectively.

Scorecard6 real differences · 4 level
Visual Vertical versus HemiStim: the parameters behind the verdict, then further details
ParameterVisual VerticalHemiStim
Price$11.99$9.99 — better
Rating2.0 (5 ratings)2.4 (5 ratings) — better
Positive reviews100.0% of reviews — better37.5% of reviews
Number of ratings55
Update frequencyEvery 38 monthsEvery 8 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.612.0 — better
Further details — not scored
Size10 MB1 MB
Age rating12+4+
DeveloperClear Health MediaLinsay Associates, LLC

Customer experience

Visual Vertical

All ratings5 ratings
Positive20.0%
Neutral0.0%
Negative80.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

HemiStim

All ratings5 ratings
Positive40.0%
Neutral0.0%
Negative60.0%
Written reviews8 reviews
Positive37.5%
Neutral12.5%
Negative50.0%

In-app purchases

None

Visual Vertical

No in-app purchases

None

HemiStim

No in-app purchases

Questions

Is Visual Vertical free?
Visual Vertical costs $11.99, with no in-app purchases.
Is HemiStim free?
HemiStim costs $9.99, with no in-app purchases.
Which has better reviews, Visual Vertical or HemiStim?
HemiStim is rated higher. Visual Vertical averages 2.0 out of 5 from 5 ratings, while HemiStim averages 2.4 from 5 ratings.
Do Visual Vertical or HemiStim have ads?
Neither Visual Vertical nor HemiStim shows ads.
Which is updated more often, Visual Vertical or HemiStim?
Visual Vertical ships an update every 38 months, and HemiStim every 8 months. Most recently, Visual Vertical was updated on September 24, 2026 and HemiStim on September 14, 2026.

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