# K vs OptoReflex

The clearest difference is price: K at Free against OptoReflex's $0.99. K also leads on iOS requirement (8.0 vs 17.0). OptoReflex's advantage is in-app purchases (none vs 1) and update cadence (weekly vs every 32 months). On ads and device support there is nothing between them.

K is free to download; OptoReflex costs $0.99 up front. K sells 1 in-app purchase, starting at $51.99 per year. OptoReflex asks for nothing beyond the download.

K ships an update every 32 months, OptoReflex weekly. The most recent releases landed on November 3, 2026 and November 10, 2026 respectively.

## The numbers

| Metric | K | OptoReflex |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/k-d-color-contrast-sensitivity/id1530827184/reviews)** | — |
| Number of ratings | **1** | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 32 months | **Weekly** |
| Monetization | Free with in-app purchases | — |
| Size | 64 MB | 3 MB |
| Requires iOS | **8.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 12+ | 4+ |
| Developer | [King-Devick Test, LLC](https://appshunter.io/developer/424793545) | [Isaias Fiuza Cabral](https://appshunter.io/developer/1896699635) |

## What reviewers say

### K

[App page](https://appshunter.io/ios/app/k-d-color-contrast-sensitivity/id1530827184)

This application helps clinicians monitor and track the progression of Age-Related Macular Degeneration (AMD). It can be used by patients for home screening, with results remotely monitored by clinical staff. Early detection of wet AMD is crucial for timely treatment.

**Highlights:** Monitor AMD progression, Track dry to wet AMD, Home screening tool, Remote monitoring by clinicians, Early detection of wet AMD

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Annual Subscription | $51.99 | per year |


### OptoReflex

[App page](https://appshunter.io/ios/app/optoreflex-eye-tests/id6778753671)

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

**In-app purchases:** none


## Frequently asked questions

### Is K free?

K is free to download, with in-app purchases available.

### Is OptoReflex free?

OptoReflex costs $0.99, with no in-app purchases.

### Do K or OptoReflex have ads?

Neither K nor OptoReflex shows ads.

### Which is updated more often, K or OptoReflex?

K ships an update every 32 months, and OptoReflex weekly. Most recently, K was updated on November 3, 2026 and OptoReflex on November 10, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*