# Linsen vs TK

The clearest difference is review sentiment: TK at 65% against Linsen's 0%. TK also leads on price (Free vs $5.99) and update cadence (every 5 weeks vs every 5 months). Linsen's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 18.0). On ads and in-app purchases there is nothing between them.

TK is free to download; Linsen costs $5.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Linsen ships an update every 5 months, TK every 5 weeks. The most recent releases landed on September 16, 2026 and September 24, 2026 respectively.

## The numbers

| Metric | Linsen | TK |
| --- | --- | --- |
| Price | $5.99 | **Free** |
| Rating | — | **[1.4 (14 ratings)](https://appshunter.io/ios/app/tk-ident/id6468877043/reviews)** |
| Number of ratings | — | **14** |
| Positive reviews | 0.0% of reviews | **65.2% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 5 weeks** |
| Monetization | Paid | **Free** |
| Size | 70 MB | 192 MB |
| Requires iOS | **15.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Ronald Krueger](https://appshunter.io/developer/997309197) | [Techniker Krankenkasse (TK)](https://appshunter.io/developer/355493231) |

## What reviewers say

### Linsen

[App page](https://appshunter.io/ios/app/linsen-navi/id997309198)

This app helps patients select the right intraocular lens for cataract surgery based on their diopters, eye conditions, and personal goals. It provides vendor-independent information and visual examples to prepare patients for discussions with their ophthalmologists.

**Highlights:** Intraocular lens selection based on diopters, Considers accompanying eye diseases, Supports individual patient goals, Vendor-independent information, Illustrates post-surgery visual impressions, Includes all current intraocular lens types

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

**In-app purchases:** none


### TK

[App page](https://appshunter.io/ios/app/tk-ident/id6468877043)

This app allows secure access to digital health services using your health insurance ID. It enables login to various health applications, manages registered devices, and handles consent settings for your health data.

**Highlights:** Create and use personal health ID, Login to digital health applications, Manage registered devices, Manage consents and authorizations, Secure identification via ID card or health card

**In-app purchases:** none


## Frequently asked questions

### Is Linsen free?

Linsen costs $5.99, with no in-app purchases.

### Is TK free?

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

### Do Linsen or TK have ads?

Neither Linsen nor TK shows ads.

### Which is updated more often, Linsen or TK?

Linsen ships an update every 5 months, and TK every 5 weeks. Most recently, Linsen was updated on September 16, 2026 and TK on September 24, 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.*