Cookie policy
Last updated [date] · Version [1.0] · Previous versions
The short version
- We use two kinds of storage: what the tool needs, and optional cookies for ads and a visit count.
- The optional ones are off until you choose, and you can change your mind any time.
- Your prescription is never stored in a cookie.
- The tool works the same whatever you pick.
This summary is part of the policy. The full text below is the legal version.
1. What this page covers
This page lists the cookies and similar device storage this site uses. How we handle your numbers is in the privacy policy.
2. What we use
| Name | Purpose | Category | Provider | Duration |
|---|---|---|---|---|
lf_consent | Remembers your cookie choice. | Strictly necessary | This site | [12 months] |
lf_theme | Remembers light, dark or system theme on this device. | Strictly necessary (device preference) | This site | Until you clear site data |
lf_scale | Remembers your screen scale so lenses draw at real size. | Strictly necessary (device preference) | This site | Until you clear site data |
lf_keep | Keeps your numbers on this device, only if you turn on "Keep my numbers". | Strictly necessary (device preference) | This site | Until you clear site data |
lf_session | Carries your numbers between pages while this tab is open. | Strictly necessary (device preference) | This site | Until you close the tab |
[cookie name] | Counts pages and clicks, never your numbers. Only with consent. | Visit count | [analytics provider] | [period] |
[cookie name] | Lets ads show and be measured. Only with consent. | Advertising | [ad partners] | Set by each partner |
[cookie name] | Ads based on your browsing elsewhere. Only with consent. | Personalised ads | [ad partners] | Set by each partner |
Swipe the table sideways for more columns.
3. Strictly necessary storage
Your cookie choice, your theme and your screen scale are saved on this device because you asked for them or because the tool needs them. They are not used to track you and are not shared.
4. Your choices
Where the law asks for it, a cookie bar offers Reject all, Manage choices and Accept all, all equally easy. You can reopen the choices at any time from Cookie settings in the footer or here.
5. Changes to this policy
If we add a cookie, it appears in the table above before it is used. The table is generated from the same list the consent settings use.