K vs Reflex
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
K
This medical app helps healthcare professionals assess vestibular dysfunction by measuring balance stance metrics. It uses a device's accelerometer to objectively score balance after voice-guided exercises. Professionals can track patient progress over time.
- Vestibular dysfunction assessment
- Measures balance stance metrics
- Uses device accelerometer
- Objective balance scoring
- Longitudinal patient assessment
- Voice-guided exercises
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K-D Balance is an FDA-cleared app used by trained professionals — including athletic trainers and coaches, physical therapists, nurses, physicians, and other trained professionals . This app is intended only for users with an existing K-D Balance account. K-D Balance assesses three balance stances: double stance, right tandem stance and left tandem stance. To use K-D Balance, an iPhone or iPod touch is secured to the individual during the assessment. A hands-free, wearable device holder may be used to help stabilise the device. After step-by-step voice guidance for each stance, an objective balance score is automatically derived by detecting the individual's movements using the device's internal accelerometer. Trained professionals can compare an individual's K-D Balance assessments longitudinally.
Reflex
This tool measures and tracks pupillary activity using an iPhone camera for quick, 5-second tests. It helps medical professionals monitor patient progress and identify deviations for clinical decision support.
- Pupillary readings via iPhone camera
- 5-second test duration
- Patient progress tracking
- Baseline feature for deviations
- Clinical decision support tool
- Rapid biomarker validation
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Measure and track autonomic pupillary activity by simply holding the iPhone up to your patient's eye for a quick 5-second test. Track patient progress using the baseline feature and frequently follow-up to determine deviations with Reflex, an accessible pupillary tool for clinical decision support. Here's what you can expect from Reflex: -Fast and reliable pupillary readings at the touch of a screen. -Track important changes and fluctuations from pupil readings over time. -Validate your clinical efforts with the state-of-the-art in rapid biomarkers. Reflex is only for medical professional use. Seek a physician's advice if you're experiencing ocular or neurological issues. Pricing & Terms: Reflex offers the following subscription option for unlimited use per period: * 1 month: $39.99 (USD) * 1 year: $399.99 (USD) This price applies to United States residents. Prices may vary in other countries respecting your local currency exchange rate. Your subscription will be charged to your iTunes account. At the end of the term, unless auto-renewables subscriptions are disabled, your subscription will automatically renew in your iTunes account. You will be charged for the regular price of your subscription within 24 hours prior to the end of the current term. You can turn off automatic renewal in your iTunes account settings at any time, but you must do so at least 24 hours before the end of the current term. Refunds will not be provided for the unused portion of any term. Reflex is a registered Class I 510(K) Exempt medical device. Privacy policy: https://reflexapp.io/privacy-policy/ Terms and conditions: https://reflexapp.io/terms-conditions
Screenshots
Verdict
The clearest difference is in-app purchases: K at none against Reflex's 5. K also leads on iOS requirement (15.0 vs 17.6). Reflex's advantage is update cadence (every 2 weeks vs every 3 months) and chart position (#132 vs unranked). On price, rating, ads and device support 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
Both are free to download. Reflex sells 5 in-app purchases, starting at $1.99 per month. K asks for nothing beyond the download.
K holds the better App Store score, 3.7 against 3.5. That said, the two scores are not equally well evidenced: Reflex has 23 ratings behind it against 3, so its average is the more settled of the two.
K ships an update every 3 months, Reflex every 2 weeks. The most recent releases landed on October 24, 2026 and October 29, 2026 respectively.
| Parameter | K | Reflex |
|---|---|---|
| Price | Free | Free |
| Rating | 3.7 (3 ratings) — better | 3.5 (23 ratings) |
| Positive reviews | — | 0.0% of reviews |
| Number of ratings | 3 | 23 — better |
| Update frequency | Every 3 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Subscription |
| Best chart rank | — | #132 — better |
| Devices | iPhone, iPod — better | iPhone |
| Requires iOS | 15.0 — better | 17.6 |
| Further details — not scored | ||
| Size | 147 MB | 22 MB |
| Age rating | 12+ | +17 |
| Developer | King-Devick Test, LLC | Brightlamp, Inc. |
Customer experience
K
Reflex
In-app purchases
K
No in-app purchases
Reflex
- Critical Care Monthly$1.991 Month
- Monthly Subscription1 Month trial$41.991 Month
- Monthly Subscription$41.991 Month
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- Yearly Subscription1 Month trial$419.991 Year
- Yearly Subscription$419.991 Year









