# 双眼视功能检查 vs i

The clearest difference is update cadence: i at every 5 weeks against 双眼视功能检查's every 4 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

双眼视功能检查 ships an update every 4 months, i every 5 weeks. The most recent releases landed on September 14, 2026 and September 18, 2026 respectively.

## The numbers

| Metric | 双眼视功能检查 | i |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 5 weeks** |
| Size | 11 MB | 166 MB |
| Requires iOS | 13.2 | **12.0** |
| Devices | iPad | iPad |
| Age rating | 12+ | 12+ |
| Developer | [Guangzhou Shijing Medical Software Co. Ltd.](https://appshunter.io/developer/389115776) | [宁波明星科技发展有限公司](https://appshunter.io/developer/1271975555) |

## What reviewers say

### 双眼视功能检查

[App page](https://appshunter.io/ios/app/id796320355)

**Features:** macOS Compatibility

**In-app purchases:** none


### i

[App page](https://appshunter.io/ios/app/i-optik-optometry/id1271975556)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is 双眼视功能检查 free?

双眼视功能检查 is free to download, with no in-app purchases.

### Is i free?

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

### Do 双眼视功能检查 or i have ads?

Neither 双眼视功能检查 nor i shows ads.

### Which is updated more often, 双眼视功能检查 or i?

双眼视功能检查 ships an update every 4 months, and i every 5 weeks. Most recently, 双眼视功能检查 was updated on September 14, 2026 and i on September 18, 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.*