# dob vs PreNumbers

The clearest difference is price: PreNumbers at Free against dob's $2.99. dob's advantage is update cadence (every 3 months vs every 8 months). On ads, in-app purchases, device support and iOS requirement there is nothing between them.

PreNumbers is free to download; dob costs $2.99 up front. dob sells 1 one-off in-app purchase and PreNumbers sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

dob ships an update every 3 months, PreNumbers every 8 months. The most recent releases landed on October 1, 2026 and September 25, 2026 respectively.

## The numbers

| Metric | dob | PreNumbers |
| --- | --- | --- |
| Price | $2.99 | **Free** |
| Rating | **[1.0 (1 ratings)](https://appshunter.io/ios/app/dob-visual-perception/id981954512/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 8 months |
| Monetization | Paid | — |
| Size | 78 MB | 42 MB |
| Requires iOS | 12.0 | 12.0 |
| Devices | iPad | iPad |
| Age rating | 4+ | 4+ |
| Developer | [Rene Fehr-Biscioni](https://appshunter.io/developer/969998405) | [IntegraTools GmbH](https://appshunter.io/developer/618103816) |

## What reviewers say

### dob

[App page](https://appshunter.io/ios/app/dob-visual-perception/id981954512)

This app offers exercises to train essential visual skills like attention, coordination, and memory. It's designed for learners of all ages, including children and individuals undergoing rehabilitation, and can be customized to individual needs.

**Highlights:** Visual Attention training, Ocular motility exercises, Hand and Eye Coordination, Motion Perception, Contrast Sensitivity, Face and facial expression recognition, Color Recognition and differentiation, Figure-Ground Perception

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| All exercises | $11.99 | one-time |


### PreNumbers

[App page](https://appshunter.io/ios/app/prenumbers/id1142502437)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| All exercises | $44.99 | one-time |


## Frequently asked questions

### Is dob free?

dob costs $2.99, and also offers in-app purchases.

### Is PreNumbers free?

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

### Do dob or PreNumbers have ads?

Neither dob nor PreNumbers shows ads.

### Which is updated more often, dob or PreNumbers?

dob ships an update every 3 months, and PreNumbers every 8 months. Most recently, dob was updated on October 1, 2026 and PreNumbers on September 25, 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.*