---
title: "OKN Viewer: Nystagmus - Reviews, Revenue and Downloads in United States | Apple App Store"
description: "Observe and record optokinetic nystagmus (OKN) on your iPhone or iPad.  OKN Viewer is a simple educational app for displaying moving stripe stimuli and observing optokinetic nystagmus (OKN) and eye mo"
---

# OKN Viewer: Nystagmus — United States
> Record & Observe Eye Movements

![OKN Viewer App Icon](https://is1-ssl.mzstatic.com/image/thumb/Purple221/v4/0f/20/0d/0f200dd3-72ad-e5f4-d26a-8777b8f94797/AppIcon-0-0-1x_U007epad-0-1-85-220.jpeg/434x0w.png)

**Developer:** [Unknown](https://apptail.io/developer/unknown-Lmhb)
**Category:** Medical
**Rating:** 3.7/5 (3 ratings)
**Price:** $1.99
**Bundle ID:** com.ishida.isihda.nystagmusTest
**Store:** Apple App Store
**Country:** United States
**Version:** 1.5 (released 2026-09-27)
**Original Release:** 2024-09-19
**Languages:** English, Japanese

**App Store Link:** [Download on Apple App Store](https://apps.apple.com/us/app/app/id6695726882)
**AppTail Page:** [https://apptail.io/app/okn-viewer-nystagmus-KdEt/united-states](https://apptail.io/app/okn-viewer-nystagmus-KdEt/united-states)

## OKN Viewer Description
Observe and record optokinetic nystagmus (OKN) on your iPhone or iPad.

OKN Viewer is a simple educational app for displaying moving stripe stimuli and observing optokinetic nystagmus (OKN) and eye movements.

Choose from four stimulus directions — up, down, left, and right. Adjust the speed, stripe width, and colors to suit your needs, and use the front-facing camera to record eye movements while viewing the OKN stimulus.

Your latest recording can be reviewed immediately, while previous recordings remain available in the video library.


KEY FEATURES

■ FOUR-DIRECTION OKN STIMULATION
Choose from up, down, left, and right stimulus directions.

■ ADJUSTABLE STIMULUS SETTINGS
Customize the stimulus to suit your needs:

- Speed: Slow / Normal / Fast
- Stripe width: Thin / Normal / Thick
- Customizable stripe colors

■ RECORD EYE MOVEMENTS
Use the front-facing camera to record eye movements while viewing the OKN stimulus.

■ QUICKLY REVIEW YOUR LATEST RECORDING
After recording, you can immediately open and review your latest video.

■ RECORDING LIBRARY
View and play your previous recordings in one place.

■ SAVE VIDEOS TO PHOTOS
Select recordings and save them to your Photos library when needed.


SIMPLE AND READY TO USE

No complicated setup is required.

Open OKN Viewer and start displaying an OKN stimulus immediately.

Adjust the direction, speed, stripe width, and colors as needed, then observe or record eye movements.

Your stimulus settings are saved and remain available the next time you open the app.


WHO IT'S FOR

OKN Viewer may be useful for:

- Learning about optokinetic nystagmus (OKN)
- Observing eye movements
- Ophthalmology and neuro-ophthalmology education
- Learning about nystagmus and balance-related eye movements
- Medical students and healthcare professionals
- Orthoptists and orthoptic students
- Educational demonstrations and training involving eye movements


PRIVACY FOCUSED

- No advertisements
- No behavioral analytics
- Recorded videos are not automatically uploaded or transmitted

OKN Viewer does not use behavioral analytics to track how you use the app.

Recordings are stored within the app. They are not automatically sent to an external server. You can choose to save selected recordings to your Photos library.


IMPORTANT NOTICE

OKN Viewer is intended for educational, learning, and observational purposes.

It is not intended to diagnose, treat, prevent, or make clinical decisions regarding any disease or medical condition.

Do not use the app or its recordings as the sole basis for medical diagnosis or treatment decisions.

Moving visual patterns may cause dizziness, nausea, visual discomfort, or other unpleasant symptoms in some users.

Stop using the app immediately if you experience discomfort.

If you are concerned about any medical symptoms, please consult an appropriate healthcare professional.


FEEDBACK AND BUG REPORTS

You can send feedback, feature requests, and bug reports from within the app.

Your feedback helps us continue improving OKN Viewer.

## OKN Viewer Screenshots
- [Screenshot 1](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource221/v4/3c/22/cc/3c22cc9d-abd8-870f-ca95-8b5654ddd4c6/Apple_iPhone_11_Pro_Max_Screenshot_1.jpg/1242x2688.png)
- [Screenshot 2](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/c8/6b/f7/c86bf728-2512-2bfd-f6b3-aa712f0039a4/Apple_iPhone_11_Pro_Max_Screenshot_2.jpg/1242x2688.png)
- [Screenshot 3](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/54/41/bf/5441bf51-9643-f8b6-8e0c-f625e4f133db/Apple_iPhone_11_Pro_Max_Screenshot_3.jpg/1242x2688.png)
- [Screenshot 4](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource211/v4/ed/49/c0/ed49c0fb-482c-55a1-9ee9-0a097aa46586/Apple_iPhone_11_Pro_Max_Screenshot_4.jpg/1242x2688.png)
- [Screenshot 5](https://is1-ssl.mzstatic.com/image/thumb/PurpleSource221/v4/6c/1f/91/6c1f91a0-c812-eb72-19f9-a303241e1914/Apple_iPhone_11_Pro_Max_Screenshot_5.jpg/1242x2688.png)

## OKN Viewer Rating Breakdown in United States
- 5 stars: 2 (67%)
- 4 stars: 0 (0%)
- 3 stars: 0 (0%)
- 2 stars: 0 (0%)
- 1 stars: 1 (33%)

## OKN Viewer Reviews in United States

### ***** "Nystagmus test"
Very helpful and useful
-- Neuro-ophthalmology, 2025-10-07

[View all OKN Viewer reviews and detailed analytics on AppTail](https://app.apptail.io/signup?utm_campaign=ai-crawl&utm_content=reviews)


## OKN Viewer Store Rankings
| Chart | Country | Category | Rank |
|-------|---------|----------|------|
| Top Paid | Germany | Medical | #36 |
| Top Grossing | Russia | Medical | #77 |
| Top Paid | Russia | Medical | #142 |
| Top Paid | Finland | Medical | #222 |

## OKN Viewer Discovered Keywords
- okn viewer
- nystagmus


## OKN Viewer Available In
- [United States](https://apptail.io/app/okn-viewer-nystagmus-KdEt/united-states)
- [Japan](https://apptail.io/app/okn-viewer-nystagmus-KdEt/japan)
- [India](https://apptail.io/app/okn-viewer-nystagmus-KdEt/india)
- [France](https://apptail.io/app/okn-viewer-nystagmus-KdEt/france)
- [Russia](https://apptail.io/app/okn-viewer-nystagmus-KdEt/russia)
- [Italy](https://apptail.io/app/okn-viewer-nystagmus-KdEt/italy)
- [Spain](https://apptail.io/app/okn-viewer-nystagmus-KdEt/spain)
- [Indonesia](https://apptail.io/app/okn-viewer-nystagmus-KdEt/indonesia)
- [Ireland](https://apptail.io/app/okn-viewer-nystagmus-KdEt/ireland)
- [Israel](https://apptail.io/app/okn-viewer-nystagmus-KdEt/israel)
- [Kazakhstan](https://apptail.io/app/okn-viewer-nystagmus-KdEt/kazakhstan)
- [Malaysia](https://apptail.io/app/okn-viewer-nystagmus-KdEt/malaysia)
- [Netherlands](https://apptail.io/app/okn-viewer-nystagmus-KdEt/netherlands)
- [Norway](https://apptail.io/app/okn-viewer-nystagmus-KdEt/norway)
- [New Zealand](https://apptail.io/app/okn-viewer-nystagmus-KdEt/new-zealand)
- [Sweden](https://apptail.io/app/okn-viewer-nystagmus-KdEt/sweden)
- [Singapore](https://apptail.io/app/okn-viewer-nystagmus-KdEt/singapore)
- [Taiwan](https://apptail.io/app/okn-viewer-nystagmus-KdEt/taiwan)
- [Ukraine](https://apptail.io/app/okn-viewer-nystagmus-KdEt/ukraine)
- [Vietnam](https://apptail.io/app/okn-viewer-nystagmus-KdEt/vietnam)
- [Austria](https://apptail.io/app/okn-viewer-nystagmus-KdEt/austria)
- [South Africa](https://apptail.io/app/okn-viewer-nystagmus-KdEt/south-africa)
- [Azerbaijan](https://apptail.io/app/okn-viewer-nystagmus-KdEt/azerbaijan)
- [Chile](https://apptail.io/app/okn-viewer-nystagmus-KdEt/chile)
- [Denmark](https://apptail.io/app/okn-viewer-nystagmus-KdEt/denmark)
- [Dominican Republic](https://apptail.io/app/okn-viewer-nystagmus-KdEt/dominican-republic)
- [Algeria](https://apptail.io/app/okn-viewer-nystagmus-KdEt/algeria)
- [Finland](https://apptail.io/app/okn-viewer-nystagmus-KdEt/finland)

---

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