K vs Vision Simulator
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
K
This application facilitates the administration of a rapid eye movement test for reading assessment. It compares performance against age-related norms for individuals aged 6-14+, helping to identify potential candidates for reading intervention programs.
- Reads numbers from test cards
- Measures speed and accuracy
- Compares results to age norms
- Identifies candidates for intervention
- Administered in under two minutes
- Validated by peer-reviewed studies
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The King-Devick Test involves reading aloud a series of single digit numbers from left to right on three test cards. Performance is based on speed and accuracy and results are instantly compared to age-related normative data for subjects 6-14+ years old. Testing administrators can quickly identify subjects that may be prime candidates for the King-Devick Reading Acceleration Program as an effective intervention. -Reliable: K-D Test has been extensively researched and validated by peer-reviewed studies -Quick: K-D Test Pro Reading can be easily administered in two minutes or less -Objective: Performance immediately compared to age-related normative data for subjects 6-14+ years old This app is intended ONLY for professional users with an existing K-D Test Pro Reading account.
Vision Simulator
Experience the world through the eyes of someone with various vision conditions. This tool uses your camera or photos to simulate effects like nearsightedness, astigmatism, cataracts, and glaucoma, aiding understanding for patients, students, and the curious. It offers adjustable severity and side-by-side comparisons.
- Simulates multiple vision conditions
- Uses live camera or uploaded photos
- Adjustable severity sliders
- Side-by-side comparison mode
- Built-in sample scenes
- Offline functionality
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See the world the way someone with an eye condition does. Vision Simulator applies realistic, clinically informed vision effects to your live camera or any photo. Point it at a room, a face, a street at night or an eye chart, then switch conditions to see how each one changes sight. It was built by Dr. Ryan Evans, OD, a practicing optometrist, to help patients and families understand what an eye condition does to vision. WHO IT'S FOR • Families who want to understand what a parent or child is going through • Eye care professionals explaining a diagnosis in the exam room • Optometry, medical and nursing students • Teachers, caregivers, designers and anyone curious about vision 10 CONDITIONS • Myopia (nearsightedness): with Snellen acuity presets • Astigmatism: with adjustable axis • Cataract: yellowing, glare and contrast loss • Glaucoma: peripheral field loss by stage, down to end-stage tunnel vision • Age-Related Macular Degeneration (AMD): distortion early, a dark central blind spot when advanced • Diabetic Retinopathy: hemorrhages, exudates and vitreous hemorrhage by stage • Color Vision Deficiency: red, green and blue types • Floaters & Posterior Vitreous Detachment (PVD) • Retinitis Pigmentosa (RP): narrowing tunnel vision • Presbyopia: the near-focus blur that starts in your 40s Plus Normal Vision, a clear reference to compare against. FREE • Live camera and photo upload • 6 built-in sample scenes, including a reading test, eye chart and Amsler grid • Normal Vision plus 3 conditions: Myopia, Astigmatism and Cataract • Adjustable severity • Plain-language notes for each condition PRO: ONE-TIME $4.99 UNLOCK No subscription. Pay once, keep it. • 7 more conditions: Glaucoma, AMD, Diabetic Retinopathy, Color Blindness, Floaters/PVD, Retinitis Pigmentosa and Presbyopia • Combine multiple conditions at once, such as cataract plus glaucoma • Side-by-side Compare: drag to wipe between normal and simulated vision • Family Sharing supported • Restore your purchase anytime on your devices PRIVACY • No ads • No account needed • Data Not Collected: images are processed on your device and are never stored or shared An internet connection is required to use the app. IMPORTANT Vision Simulator is for education and demonstration only. It is not a diagnostic tool and does not replace a comprehensive eye examination. Simulations are approximations, and every person's vision is different. If you notice changes in your vision, see your eye doctor.
Screenshots
Verdict
The clearest difference is in-app purchases: K at none against Vision Simulator's 1. K also leads on iOS requirement (8.0 vs 15.0). Vision Simulator's advantage is update cadence (every 3 days vs every 14 months) and device support (3 vs 1). On price, rating, ratings volume and ads 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. Vision Simulator sells 1 one-off in-app purchase. K asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 5.0 for K against 5.0 for Vision Simulator. Both are backed by a comparable volume of ratings — 1 and 1 respectively.
K ships an update every 14 months, Vision Simulator every 3 days. The most recent releases landed on November 2, 2026 and October 31, 2026 respectively.
| Parameter | K | Vision Simulator |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) | 5.0 (1 ratings) |
| Number of ratings | 1 | 1 |
| Update frequency | Every 14 months | Every 3 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Paid |
| Devices | iPad | iPhone, iPad, iPod — better |
| Requires iOS | 8.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 57 MB | 46 MB |
| Age rating | 12+ | 4+ |
| Developer | King-Devick Test, LLC | Ryan Evans |
Customer experience
K
Vision Simulator
In-app purchases
K
No in-app purchases
Vision Simulator
- Vision Simulator Pro$4.99






