Terms of Use

Version 1.0 · In effect from 22 August 2026

This is the agreement between you and Eidovelle Labs about your use of the Eidovelle app. It is written to be read. If a sentence in it does not make sense to you, ask us at [email protected] before you agree to it.

1. What this agreement covers

This agreement is between you and Eidovelle Labs ("we", "us", "our"). It covers the Eidovelle app for iPhone, everything inside it, and this website.

You accept it by installing or using the app. If you do not accept it, do not install the app, and delete it if you already have.

Two other documents form part of it and are incorporated by reference. Read both before you agree to this one:

• The safety information, which carries the full list of who must not use Eidovelle and the limits compiled into the app.
• The privacy policy, which describes what the app writes to your phone and what leaves it, which is nothing.

Your purchase itself is a separate matter between you and Apple. See section 10.

2. You must be 18 or over

Eidovelle is for adults only. You must be 18 or over to use it. There is no version of this product suitable for a child and there is no parental consent that makes it suitable for one.

The reason is the hazard rather than the subject matter. Photosensitivity most often first appears before the age of 20, most commonly between 7 and 19, so the age group most likely to have an undiagnosed sensitivity to flickering light is precisely the group this product excludes.

The app asks your age before anything else and stops there if the answer is under 18. By using Eidovelle you confirm that you are 18 or over and that you answered that question truthfully. If you are under 18, you have no licence to use the app under this agreement, and using it anyway is a breach of it.

If you are responsible for a person under 18 who has installed Eidovelle, remove it from their device, and write to us at [email protected] if you would like us to confirm that we hold nothing about them, which we do not.

3. What Eidovelle is, and what it is not

Eidovelle pulses the camera flash LED on the back of your phone, as a torch, at rates between 0.5 and 13.0 Hz, while you lie with your eyes closed, for between five and thirty minutes, with music and narration playing.

Eidovelle is not a medical device and does not diagnose, treat, cure, or prevent any medical condition. It does not monitor or alleviate any condition, and it is not a test for any condition. For medical advice, diagnosis, or treatment, speak to a healthcare professional.

We make no claim that Eidovelle will produce any particular experience, any particular effect, or any benefit of any kind. Some people see moving geometric colour through a closed eyelid. Some see very little. We cannot tell you in advance which you will be, and getting little from it is not a fault in the product.

No medicines or medical devices regulator has assessed this product. The limits described in the safety information are self-imposed and enforced by us alone. As at the date at the top of this page, no clinician has reviewed them.

4. Photosensitivity: what you are acknowledging

This section is the reason this agreement exists rather than the standard one. Read it properly.

By using Eidovelle you acknowledge each of the following.

• Flickering light can bring on a seizure. Rhythmic light of the kind this app produces can provoke a seizure in a person who is photosensitive. This is the principal hazard of the product and no design choice removes it.
• You may be photosensitive without knowing. Around half of the people whose brains respond abnormally to flicker have never been told they are photosensitive. A first seizure has to happen somewhere. "It has never happened to me" is not an all-clear.
• The frequencies used are not free of risk. The app never operates between 13.5 and 25.0 Hz, which is where published sources put the risk highest. The top of the range it does use, 13.0 Hz, sits inside the wider range that published sources treat as capable of provoking a seizure. Avoiding the maximum lowers the risk. It does not put the light outside the range where the risk exists.
• Closing your eyes is not protection. Light passes through an eyelid, and the eyelid spreads it across more of the retina rather than less. Eye closure is also a trigger in its own right for some people, with no light involved.
• Effects short of a seizure are common. Headache, eye strain, dizziness, nausea and disorientation happen to people who are not photosensitive at all.
• Other effects are possible. Flickering light can bring on dissociation, anxiety, distressing or hallucinatory experiences, and migraine. One layer of the audio can be felt in the body as falling and can become dizziness or nausea with the light off entirely.
• No figure exists for how often any of this happens in the way this product is used, which is alone, at home, unsupervised. The published figures come from supervised laboratory sessions with pre-screened participants, and they do not transfer.
• You have read the safety information at eidovelle.com/safety, including the full list of who must not use Eidovelle, and none of it applies to you.

If any exclusion on the safety page applies to you, or you are not sure whether one does, you do not have permission to use the light under this agreement. Ask a doctor. The audio worlds are available either way.

5. The screening, and answering it honestly

The app asks a set of questions before it will run light. A yes to any of the questions that gate the light closes the light on that phone, and Unsure is counted as a yes. There is no button that says you accept the risk and no version of the light we will sell past that point.

You agree to answer those questions truthfully and completely, and to answer the questions the app asks before each voyage about sleep, alcohol and withdrawal truthfully each time.

You agree not to attempt to get past a screening outcome that closed the light, whether by answering differently, by reinstalling the app, by using someone else's device, or by any other means. We have no technical way to prevent this and we are not going to pretend otherwise. It is a term of the agreement instead, and if you do it, you are using the app without a licence.

The screening is not a test for epilepsy or for photosensitivity. It decides one thing only, which is whether this app will run light for you. Getting through it is not a finding about your health, it is not a medical opinion, and it is not an assurance that flicker will not affect you.

6. How you agree to use it

• Lying down, or seated and supported. Never while driving, never while operating machinery, never in water, never at a height, never anywhere a lapse in awareness would injure you, and never while responsible for the care of another person.
• Not while impaired. Not after alcohol, not on recreational drugs, not while withdrawing from alcohol or a sedative, and not on very little sleep. Each of those lowers the seizure threshold and the app asks about the ones it can.
• Stop if anything feels wrong. Cover one eye with your palm, turn the phone face down, and end the voyage by touching the lower half of the screen. If you had twitching, muscle spasms, a convulsion, a lapse in awareness, confusion, a strong feeling of déjà vu, or strong dizziness, do not start another voyage and speak to a doctor before you use the light again.
• Do not use it on anybody else. Eidovelle is licensed to you for your own use. Do not run a voyage for another person, do not show the light to anyone who has not been through the screening on their own device, and do not use it where someone else can see the light.
• Do not record the light and publish it. A recording of the torch pulsing is a flashing video, and putting one where an unscreened person can encounter it is the exact harm the design is arranged to avoid.

7. Assumption of risk

This section is a real one and it is written plainly rather than in the usual way.

You use Eidovelle voluntarily, and you accept the risks described in section 4. Those risks include a seizure, and they include the injuries a seizure can cause, such as those from a fall.

You accept those risks knowing that:

• we have told you what the hazard is, in plain terms, on the safety page and again in section 4;
• we have told you which of the limits in the app rest on published sources and which are our own judgement, and that roughly half of them are judgement;
• we have told you that no regulator has assessed this product and that no clinician has reviewed its limits;
• the screening cannot tell you whether you are photosensitive, and nothing short of a doctor and an EEG can; and
• you can decline the risk at no cost by not using the light, and every world is available as audio at the same price if you do.

Nothing in this section applies to a risk we did not tell you about, to anything caused by our own negligence, or to anything the law of the place where you live does not permit you to give up. See section 16.

8. Your licence

We grant you a personal, non-exclusive, non-transferable, revocable licence to install and use one copy of Eidovelle on Apple-branded devices that you own or control, as permitted by the App Store Terms of Service and by this agreement, for your own personal and non-commercial use.

You are buying access, not the software. We keep everything we have not expressly given you here.

9. What you must not do

• Modify, adapt, translate, decompile, disassemble or reverse engineer the app, or attempt to derive its source code, except to the extent the law expressly permits you to despite this restriction.
• Change, defeat, bypass or interfere with anything that limits the light: the frequency bounds, the excluded band, the modulation depth cap, the torch level cap, the duration caps, the screening, the pre-voyage questions, the hold placed after an uncomfortable voyage, the stop control, or the app's response to the iOS Dim Flashing Lights setting. This is the most serious restriction in this agreement and breaching it ends your licence immediately.
• Build, publish or distribute anything that runs Eidovelle's content outside the app, or that reproduces its light pattern in another program.
• Copy, sell, rent, sublicense, lease or redistribute the app, its audio, its narration or its artwork, in whole or in part.
• Remove or obscure any notice of ownership in the app.
• Use the app in a way that breaks any law that applies to you, or use it if you are barred from doing so under United States law or the law of the place where you live.

10. Purchases, subscriptions and the free trial

Eidovelle is sold on the App Store and nowhere else. Apple takes the payment and Apple is the merchant of record. We never see your card, your Apple Account, your name or your email address.

Two worlds are free with no time limit: The Ascent and Undersong Reef, at every length they were built for, with the light and as audio. A further set of worlds is free in any given week, chosen on your phone from the date. If we ever change how the library is sold, anyone who already has the two permanently free worlds keeps them.

Everything else is available by subscription:

• $4.99 a month. This renews every month at $4.99 until you cancel.
• $34.99 a year, with the first 21 days free. Cancel any time in those 21 days and you are not charged. If you do not cancel, $34.99 is charged at the end of the free period and every year after that until you cancel. The free trial is on the annual plan only, one per Apple Account, and Apple decides your eligibility for it rather than we do.

Both are auto-renewing subscriptions charged to your Apple Account. Payment is taken when you confirm the purchase and at each renewal. A subscription renews automatically unless you turn off auto-renew at least 24 hours before the end of the current period. Manage and cancel in the Settings app on your iPhone, under your name, then Subscriptions. The five taps are written out here. Deleting the app does not cancel a subscription.

Cancelling stops the next charge. You keep what you paid for until the end of the period you have already paid for, and after that you keep the app and the free tier.

Prices are in United States dollars and Eidovelle is sold in the United States storefront. Prices may change. If a subscription price changes, Apple will ask for your agreement before charging the new price, and if you do not agree the subscription does not renew.

11. Founding

Founding costs $99.99, once. It is a one-time purchase inside the app, not a subscription. There is no renewal and no expiry, and it covers the whole library including worlds published later.

It is offered while it is offered and it may be withdrawn at any time. If it is withdrawn, everyone who bought it keeps it, on the terms it was bought on.

What it does not do: it does not entitle you to any particular number of future worlds, to any particular release schedule, or to any world we do not in fact publish. If Eidovelle stops being developed, Founding continues to cover the worlds that exist at that point and nothing more.

Founding is tied to the Apple Account that bought it and moves with that account when you restore purchases on another device.

12. Refunds

Apple is the merchant for everything bought in the app, so refunds are Apple's to give, not ours. Ask through reportaproblem.apple.com or through Report a Problem in your Apple purchase history. We cannot issue an App Store refund on your behalf.

We will help. If you paid and then found the light was not available to you, whether because the screening stopped you, because your phone could not hold the timing, or for any other reason, write to [email protected] and we will write to Apple in support of your refund. If Apple refuses and you think that is wrong, tell us and we will write to them again.

Nothing in this section affects any right to a refund you have under consumer law where you live.

13. Ownership of the app and its contents

Eidovelle, its software, its music, its narration, its artwork, its name and its marks belong to Eidovelle Labs or to the people we licensed them from. Nothing in this agreement transfers any of that to you.

Your voyage log and any note you write in it are yours. They are written to your phone, they never reach us, and we claim no rights over them. See the privacy policy.

14. Privacy

The privacy policy forms part of this agreement.

The part of it that matters most here: your screening outcome and the contents of your voyage log stay on your device, in every version, always. The app has no account and no sign-in, and this version of it sends nothing at all, so there is nothing about you for us to hold, read, sell or disclose. When anything about that changes, the privacy policy is amended and re-dated before or on the day the change reaches you, never afterwards.

15. Disclaimer of warranties

We have built this carefully and we have written down what we do not know. What follows is the legal position, and it is not a hedge against the statements above.

Except where the law says otherwise, Eidovelle is provided as it is and as it is available, without warranty of any kind, whether express, implied or statutory, including any implied warranty of merchantability, of fitness for a particular purpose, of quiet enjoyment, or of non-infringement.

In particular, we do not warrant that the app will be uninterrupted or free of defects, that any defect will be corrected, that torch timing will be accurate on your particular handset, or that a voyage will produce any particular experience or any benefit.

We do not warrant that using Eidovelle will not harm you. The hazard described in section 4 is real, and this agreement does not ask you to believe otherwise.

Some jurisdictions do not allow the exclusion of implied warranties, so some of this may not apply to you, and you may have other rights that vary from place to place.

16. Limitation of liability

Nothing in this agreement limits or excludes our liability for death or personal injury caused by our negligence, for fraud or fraudulent misrepresentation, or for anything else that the law does not allow to be limited or excluded. If anything below conflicts with that sentence, that sentence wins.

Subject to that, and to the fullest extent the law allows:

• we are not liable for indirect, incidental, special, consequential, exemplary or punitive damages, or for loss of profits, revenue, data or goodwill, however caused;
• our total liability arising out of or in connection with this agreement or your use of Eidovelle is limited to the greater of the amount you paid us or paid Apple for Eidovelle in the twelve months before the claim arose, and one hundred United States dollars;
• we are not liable for anything arising from your use of the app in breach of this agreement, including use by a person under 18, use after a screening outcome closed the light, use while impaired, or use in a setting section 6 says not to use it in.

These limits apply even if a remedy fails of its essential purpose, and they survive the end of this agreement.

Some jurisdictions do not allow some of these limits, so they may not apply to you in full. Nothing here affects your statutory rights as a consumer.

17. Indemnity

You agree to indemnify us against any claim, loss, liability or cost, including reasonable legal fees, arising from your use of Eidovelle in breach of this agreement, in particular from using it while under 18, from using it after a screening outcome closed the light to you, from defeating or bypassing any of the limits in section 9, or from running a voyage for or in front of another person.

This does not apply to anything caused by our own negligence or breach.

18. Suspension and ending this agreement

You may end this agreement at any time by deleting the app. Cancel any subscription first, because deleting the app does not cancel one.

Your licence ends automatically if you breach any term of this agreement, and immediately if you breach the restriction on defeating the limits on the light. On that happening you must stop using the app and delete it.

We may stop offering Eidovelle, or any part of it, at any time. If we do, sections 13, 15, 16, 17 and 21 survive, and so does any obligation either of us already owed the other.

19. Changes to the app and to these terms

We may change the app, add worlds, remove worlds, and change how it works.

If we change these terms materially, we will say what changed and when, and the version and date at the top of this page will change with it. We keep the previous wording available so you can see what it used to say. Continuing to use the app after a change means you accept the changed terms, and if you do not accept them, stop using the app and cancel any subscription.

If a change to these terms or to the safety information affects what you agreed to when you first consented in the app, the app asks you to consent again rather than assuming.

20. Terms required because you got this from the App Store

These terms apply because Eidovelle is licensed to you through the App Store. Where they conflict with anything else in this agreement, they win.

• This agreement is between you and us, not Apple. Apple is not a party to it, and we alone are responsible for Eidovelle and its contents.
• Scope of the licence. Your licence is limited to a non-transferable licence to use Eidovelle on Apple-branded products that you own or control, as permitted by the Usage Rules in the App Store Terms of Service, except that it may be accessed by other accounts through Family Sharing or volume purchasing where Apple permits that.
• Maintenance and support. We are solely responsible for providing any maintenance and support for Eidovelle. Apple has no obligation to provide any.
• Warranty. We are solely responsible for any product warranty, whether express or implied by law, to the extent it is not effectively disclaimed. If Eidovelle fails to conform to any applicable warranty, you may notify Apple, and Apple will refund the purchase price to you. To the maximum extent permitted by law, Apple has no other warranty obligation of any kind with respect to Eidovelle.
• Product claims. We, not Apple, are responsible for addressing any claim by you or a third party relating to Eidovelle or your possession or use of it, including product liability claims, any claim that Eidovelle fails to conform to a legal or regulatory requirement, and any claim arising under consumer protection, privacy or similar legislation.
• Intellectual property claims. If a third party claims that Eidovelle infringes their intellectual property rights, we, not Apple, are solely responsible for the investigation, defence, settlement and discharge of that claim.
• Legal compliance. You confirm that you are not located in a country subject to a United States Government embargo or designated by the United States Government as a terrorist-supporting country, and that you are not listed on any United States Government list of prohibited or restricted parties.
• Third party beneficiary. Apple and Apple's subsidiaries are third party beneficiaries of this agreement, and on your accepting it Apple has the right, and is deemed to have accepted the right, to enforce it against you as a third party beneficiary.
• Contact. Questions, complaints or claims about Eidovelle go to [email protected]. Anything about something that happened to you during or after a voyage goes to [email protected] instead, which is read every day.

21. Governing law and disputes

This agreement is governed by the law of the state in which Eidovelle Labs is established and by the federal law of the United States, without regard to conflict of law rules.

If you live somewhere whose consumer law gives you rights that cannot be taken away by agreement, you keep those rights, and nothing in this section removes your right to bring a claim in the courts of the place where you live.

Before starting any formal proceedings, please write to us at [email protected]. Most things can be sorted out in an email, and we would rather sort them out than argue about them.

22. General

Severability. If any part of this agreement is held unenforceable, that part is limited or removed to the minimum extent necessary and the rest stays in force.

No waiver. If we do not enforce a term straight away, we have not given it up.

Assignment. You may not transfer your rights under this agreement. We may transfer ours to a successor of the business, and if we do, your rights are unaffected.

Entire agreement. This agreement, together with the safety information and the privacy policy, is the whole agreement between you and us about Eidovelle, and it replaces anything said before it.

Language. This agreement is written in English, and the English version governs.

23. Contact

Eidovelle Labs

General, billing and anything about these terms: [email protected]

Anything that happened to a person during or after a voyage: [email protected]. That address is read by a person, every day. It is not an emergency line. If you are unwell now, contact emergency services or your doctor and do not wait for us.