Comparison

King vs Optics Trainer

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

Head to head
About

King

This app provides a quick and objective sideline concussion screening test for athletes. It helps identify potential concussions by assessing eye movements, attention, and concentration through a simple number-reading exercise. Requires an existing King-Devick Online account.

Highlights
  • Objective sideline concussion screening
  • Assess eye movements and attention
  • Administer baseline and post-injury tests
  • Works offline
  • Suitable for ages 5+
Features
Read full description

This app is intended ONLY for users with an existing King-Devick Online account. The King-Devick Concussion Screening Test is an objective, remove-from-play sideline concussion screening test which can be administered by parents, coaches, athletic trainers or medical professionals in minutes. Peer reviewed published research has shown that the King-Devick Test is an accurate and reliable method to help identify athletes with concussion on the sidelines. It has particular relevance to sports such as football, hockey, soccer, and basketball in addition to all other contact or collision activities on the field or at home. The test involves reading aloud a series of single digit numbers from left to right on three test cards. The King-Devick can detect impairment of eye movements, attention, language, concentration and other areas which correlate with concussion. How does King-Devick Test work? -King-Devick Test account holders get unlimited concussion screening per athlete per year. -With the King-Devick Test App, you can administer baseline and post-injury assessments even when WiFi is not available. -All athletes establish a pre-season or pre-injury baseline test score annually. -Concussion screening for athletes as young as 5 years old.

About

Optics Trainer

Enhance your visual skills with a variety of engaging games and personalized daily workouts. Improve convergence, divergence, stereo acuity, and binocular fusion. Test and strengthen visual memory, tracking, and peripheral vision for sharper focus.

Highlights
  • Vision therapy and training
  • 28+ engaging games
  • Personalized daily workouts
  • Improve convergence and divergence
  • Enhance stereo acuity and binocular fusion
  • Test visual memory and tracking
Features
Read full description

Elevate your vision and sharpen your mind with the ultimate vision therapy and brain training app, designed to enhance: - Convergence - Divergence - Stereo Acuity - Binocular Fusion 30 Engaging Games for Vision Training, Eye Exercise & Brain Training Stay motivated and have fun while building stronger visual and cognitive skills: attention, memory, speed, tracking and problem solving. Personalized Daily Workouts A new workout every day. Every game adapts its level to you, keeping you on track toward your goals. 3D Glasses Mode Put on red-blue glasses and play games designed to train both eyes together. Test and improve: - Multiple Object Tracking - Visual Memory - Visual Discrimination - Peripheral Vision - Depth Perception Track Your Progress Follow your streak, your level in every game, and your training scores by category. Sign in to keep your progress on all your devices. Premium Unlimited play with no ads, 3D Glasses games, progress charts, and your choice of level. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. Manage or cancel in your App Store account settings. Sharper Vision. Stronger Focus. Your journey begins now! This app is for training and does not diagnose or treat any condition. Ask your eye care professional about your vision. Terms of Use - https://www.opticstrainer.com/terms-of-service/ Privacy Policy - https://www.opticstrainer.com/privacy-policy/

Screenshots

Optics Trainer4 screens

Verdict

The call

The clearest difference is rating: King at 5.0 against Optics Trainer's 4.5. King also leads on in-app purchases (none vs 3) and ads (none vs shown). Optics Trainer's advantage is update cadence (every 8 days vs every 2 months) and ratings volume (302 vs 2). On price 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Optics Trainer sells 3 in-app purchases, starting at $4.99 per 7 days. King asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

King holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: Optics Trainer has 302 ratings behind it against 2, so its average is the more settled of the two.

UpkeepUpdate frequency

King ships an update every 2 months, Optics Trainer every 8 days. The most recent releases landed on October 2, 2026 and October 15, 2026 respectively.

Scorecard7 real differences · 3 level
King versus Optics Trainer: the parameters behind the verdict, then further details
ParameterKingOptics Trainer
PriceFreeFree
Rating5.0 (2 ratings) — better4.5 (302 ratings)
Positive reviews—64.7% of reviews
Number of ratings2302 — better
Update frequencyEvery 2 monthsEvery 8 days — better
AdsNo — betterYes
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPadiPhone, iPad — better
Requires iOS9.0 — better16.4
Further details — not scored
Size243 MB476 MB
Age rating4+4+
DeveloperKing-Devick Test, LLCOptics Trainer LLC

Customer experience

King

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

Optics Trainer

All ratings302 ratings
Positive89.7%
Neutral2.6%
Negative7.6%
Written reviews17 reviews
Positive64.7%
Neutral5.9%
Negative29.4%

Bugs and requests

King

Not enough reviews yet to summarise bugs or requests.

Optics Trainer

Reported bugs

5 issues
  • Number flip game has blank tiles
  • Flower power stopped working
  • Letter delivery letter goes off-screen
  • Attention exercises stuck on level one
  • Ice flow impossible to level up

Requested features

5 requests
  • Customize peripheral vision symbols
  • Option to change symbol colors
  • Adjust number of targets in Dynamic Acuity
  • Add introductory level for Dynamic Acuity
  • Allow offline play in free version

In-app purchases

None

King

No in-app purchases

3 purchases

Optics Trainer

Subscriptions3
  • Weekly Subscription$4.997 Days
  • Monthly Subscription1 Month trial$14.991 Month
  • Annual Subscription1 Month trial$149.991 Year

Questions

Is King free?
King is free to download, with no in-app purchases.
Is Optics Trainer free?
Optics Trainer is free to download, with in-app purchases available.
Which has better reviews, King or Optics Trainer?
King is rated higher. King averages 5.0 out of 5 from 2 ratings, while Optics Trainer averages 4.5 from 302 ratings.
Do King or Optics Trainer have ads?
Optics Trainer shows ads; King does not.
Which is updated more often, King or Optics Trainer?
King ships an update every 2 months, and Optics Trainer every 8 days. Most recently, King was updated on October 2, 2026 and Optics Trainer on October 15, 2026.

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