---
title: addPower
framework: healthkit
role: symbol
role_heading: Instance Property
path: healthkit/hklensspecification/addpower
---

# addPower

The correction for nearsightedness.

## Declaration

```swift
@NSCopying var addPower: HKQuantity? { get }
```

## Discussion

Discussion This quantity uses diopter() units. The range is from 0.25 to 2.5. The right and left eyes should have the same value.

## See Also

### Accessing lens specification data

- [sphere](healthkit/hklensspecification/sphere.md)
- [cylinder](healthkit/hklensspecification/cylinder.md)
- [axis](healthkit/hklensspecification/axis.md)