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

Engage in game-based vision training exercises designed to improve eye teaming, depth perception, and reaction time. Daily workouts offer personalized challenges, with an optional VR mode for enhanced experiences. Track your progress and enhance visual skills through fun, adaptive drills.

Highlights
  • Vision therapy games
  • Daily adaptive workouts
  • Binocular vision training
  • Peripheral awareness drills
  • Red-blue 3D glasses mode
  • Progress tracking
  • VR mode available
Features
Read full description

Optics Trainer turns vision training exercises into short, game-based workouts. It started in vision therapy clinics, where eye care professionals use it with their patients, and is now available at home on iPhone, iPad and the web. WHAT YOU TRAIN • Convergence and divergence (vergence): games that ask both eyes to aim together at changing depths, with levels you can adjust • Binocular fusion and eye teaming: activities that use both eyes as a team • Stereo acuity and depth perception: spot what's nearer or farther • Monocular fixation in a binocular field (MFBF): with red-blue 3D glasses, each eye sees its own target while both stay open • Eye tracking: pursuits, saccades and steady fixation • Peripheral awareness, multiple object tracking and reaction time • Visual memory, visual discrimination, attention and processing speed GAMES AND DRILLS A large and growing library of short games for eye exercises, vision training and brain training. Each one adjusts its level to you. DAILY WORKOUT A new set of games every day, picked for your level: about 7 minutes. RED-BLUE 3D GLASSES MODE Put on red-blue glasses for games that show each eye a different image (a dichoptic display). TRACK YOUR SCORES See your streak, your level in every game and your scores by skill. One account works on iPhone, iPad, Android and the web at app.opticstrainer.com. ALSO ON META QUEST Optics Trainer VR adds VR-only activities, with MFBF built in and no glasses needed. PREMIUM 7-day free trial, then $14.99/month or $149.99/year. Unlimited play, no ads, 3D glasses games, progress charts and level choice. 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. Optics Trainer is a training app. It does not diagnose, treat or cure any condition and is not a substitute for professional eye care. If you have a vision condition or symptoms, ask your eye care professional whether home training fits your plan. 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 2) and ads (none vs shown). Optics Trainer's advantage is update cadence (every 8 days vs every 2 months) and ratings volume (307 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 2 in-app purchases, starting at $14.99 per month. 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 307 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 November 2, 2026 and November 7, 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 (307 ratings)
Positive reviews—66.7% of reviews
Number of ratings2307 — 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 MB404 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 ratings307 ratings
Positive89.9%
Neutral2.9%
Negative7.2%
Written reviews21 reviews
Positive66.7%
Neutral9.5%
Negative23.8%

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

2 purchases

Optics Trainer

Subscriptions2
  • 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 307 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 November 2, 2026 and Optics Trainer on November 7, 2026.

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