# Verticality Test vs OKN Drum

Verticality Test and OKN Drum both sit at 4.0 stars, but that hides the real split: 46% of OKN Drum's written reviews are positive against 0% of Verticality Test's. OKN Drum also leads on update cadence (every 2 weeks vs every 4 months) and ratings volume (16 vs 2). Verticality Test's advantage is in-app purchases (none vs 1) and device support (4 vs 2). On price, rating and ads there is nothing between them.

Both are free to download. OKN Drum sells 1 one-off in-app purchase. Verticality Test asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 4.0 for Verticality Test against 4.1 for OKN Drum. That said, the two scores are not equally well evidenced: OKN Drum has 16 ratings behind it against 2, so its average is the more settled of the two. Written reviews are what separate them: 0% of Verticality Test's written reviews are positive against 46% of OKN Drum's.

Verticality Test ships an update every 4 months, OKN Drum every 2 weeks. The most recent releases landed on October 2, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Verticality Test | OKN Drum |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.0 (2 ratings)](https://appshunter.io/ios/app/verticality-test/id1048555950/reviews) | **[4.1 (16 ratings)](https://appshunter.io/ios/app/okn-drum-optokinetic/id6474153180/reviews)** |
| Number of ratings | 2 | **16** |
| Positive reviews | 0.0% of reviews | **46.2% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 2 weeks** |
| Monetization | **Free** | Paid |
| Size | 62 MB | 14 MB |
| Requires iOS | **11.0** | 17.0 |
| Devices | **iPhone, iPad, iPod, Apple TV** | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [Jorge Alberto Rey Martinez](https://appshunter.io/developer/647212281) | [My Call Bag LLC](https://appshunter.io/developer/1243282862) |

## What reviewers say

### Verticality Test

[App page](https://appshunter.io/ios/app/verticality-test/id1048555950)

Assess verticality, horizontality, and depth perception using your iOS device. This app offers a novel methodology for performing these tests anywhere, under any lighting conditions. A tvOS version is available for classical testing on Apple TV.

**Highlights:** Verticality perception tests, Horizontality perception tests, Profundity perception tests, Novel testing methodology, iOS device mobility, tvOS version available

**In-app purchases:** none


### OKN Drum

[App page](https://appshunter.io/ios/app/okn-drum-optokinetic/id6474153180)

This app offers a digital optokinetic drum for vision testing and exercises. Customize stripe width, speed, and color, with options for pediatric targets. It also features a metronome and camera recording for eye movements.

**Highlights:** Adjustable stripe width and speed, Selectable black or red stripes, Pediatric targets (puppies, dinosaurs, animals), Full-screen mode, Integrated metronome, Record eye movements with camera, Upload custom images for drum

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Lifetime Access | $4.99 | one-time |


## Frequently asked questions

### Is Verticality Test free?

Verticality Test is free to download, with no in-app purchases.

### Is OKN Drum free?

OKN Drum is free to download, with in-app purchases available.

### Which has better reviews, Verticality Test or OKN Drum?

OKN Drum is rated higher. Verticality Test averages 4.0 out of 5 from 2 ratings, while OKN Drum averages 4.1 from 16 ratings.

### Do Verticality Test or OKN Drum have ads?

Neither Verticality Test nor OKN Drum shows ads.

### Which is updated more often, Verticality Test or OKN Drum?

Verticality Test ships an update every 4 months, and OKN Drum every 2 weeks. Most recently, Verticality Test was updated on October 2, 2026 and OKN Drum on October 25, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*