# OKN Viewer: Nystagmus — Observe Optokinetic Nystagmus

> App to observe and record optokinetic nystagmus with customizable visual patterns. (iPhone/iPad app by ishida yuto.)

- Source: https://appshunter.io/ios/app/okn-viewer-nystagmus/id6695726882 (this page in markdown: same URL + `.md`)
- Developer: [ishida yuto](https://appshunter.io/developer/1582923433)
- Category: Medical, Education
- Price: $1.99
- Rating: 3.70/5 from 3 App Store ratings · 1 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.0 · 1 MB
- Languages: American English, Japanese
- Released: 2024-09-19
- Data updated: 2026-08-24
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/okn-viewer-nystagmus/id6695726882/reviews.md

## What is OKN Viewer?

Even in healthy people, nystagmus naturally occurs when watching moving scenery.
This app reproduces that nystagmus on your smartphone screen and lets you record your eye movements with the front-facing camera — a simple tool to observe and experience nystagmus.

By staring at the moving stripe pattern (bands) on the screen, you can easily observe optokinetic nystagmus (OKN).
It can be used as a preview/review tool in medical, rehabilitation, and educational settings, and also answers the simple question:
“What does nystagmus actually look like?”


【Main Features】

• Adjustable stripe width
Change the width of the moving stripes intuitively with a slider.

• Adjustable moving speed
Freely set how fast the stripes move, from very slow to fast.

• Customizable stripe color
Choose colors that suit your preference and visibility to enhance the visual effect.

• Record eye movements with the front camera
Keep your gaze fixed on the screen and record your eye movements, then review them later.


【Recommended For】

• Those who want to deepen their understanding of nystagmus and optokinetic nystagmus (OKN):
physicians, medical students, orthoptists, nurses, rehabilitation staff, and clinical laboratory technologists.

• Teachers and instructors looking for an easy-to-use visual teaching material for classes, practical training, or lectures.

• Science- and medicine-oriented students, as well as general users who are interested in visual effects and how the body reacts to them.



• No advertisements



Important Notice

This app is designed as a tool for observing, learning about, and experiencing nystagmus and optokinetic nystagmus.
It is not a medical device and is not intended for diagnosis or treatment.

If you have any symptoms or concerns and need evaluation, diagnosis, or treatment, please consult a physician or other qualified healthcare professional.

## Key features

- Adjustable stripe width
- Adjustable moving speed
- Customizable stripe color
- Record eye movements with front camera
- Preview/review tool for medical settings
- Visual teaching material

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/okn-viewer-nystagmus/id6695726882/reviews.md

### 5/5 — Nystagmus test

*2025-10-07*

Very helpful and useful

## Frequently asked questions about OKN Viewer

### What is OKN Viewer?

OKN Viewer is a medical app designed to help users observe and experience optokinetic nystagmus (OKN) by displaying a moving stripe pattern on their device's screen. It also allows for the recording of eye movements using the front-facing camera.

### Is OKN Viewer a medical device?

No, OKN Viewer is not a medical device. It is intended for observation, learning, and experiencing nystagmus, not for diagnosis or treatment. For any medical concerns, consult a qualified healthcare professional.

### What are the main features of OKN Viewer?

Key features include adjustable stripe width, customizable moving speed, adjustable stripe color, and the ability to record eye movements with the front camera for later review.

### Who is OKN Viewer recommended for?

It is recommended for physicians, medical students, orthoptists, nurses, rehabilitation staff, clinical laboratory technologists, teachers, and students interested in visual effects and how the body reacts to them.

### Does OKN Viewer have advertisements?

No, OKN Viewer does not contain any advertisements, providing an uninterrupted user experience.

### What is the price of OKN Viewer?

OKN Viewer is a paid application, priced at $1.99. There are no in-app purchases or subscriptions.

### What devices is OKN Viewer compatible with?

OKN Viewer is compatible with iPhone and iPad devices.

### How often is OKN Viewer updated?

The app was last updated on February 19, 2026, indicating a recent update. The developer typically releases updates to improve functionality and add features.

## Version history (last 5 releases)

### 1.4 — 2026-02-19

Minor corrections have been made.

### 1.3 — 2025-12-04

【Revision】
・Design revisions

### 1.2 — 2024-09-25

[New feature]
Recording function: it is now possible to record and observe one's own nystagmus.

### 1.1 — 2024-09-23

Problem solved with sometimes choppy animations.

### 1.0 — 2024-09-19

No release notes.

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All apps by ishida yuto: https://appshunter.io/developer/1582923433

## Related topics

[optokinetic](https://appshunter.io/ios/topics/optokinetic)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-24.*