---
title: vertexDistance
framework: healthkit
role: symbol
role_heading: Instance Property
path: healthkit/hkglasseslensspecification/vertexdistance
---

# vertexDistance

The distance between the back of the lens and the eye, measured in mm.

## Declaration

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

## Discussion

Discussion This property’s range is from 12 to 14 mm.

## See Also

### Accessing the specification’s data

- [farPupillaryDistance](healthkit/hkglasseslensspecification/farpupillarydistance.md)
- [nearPupillaryDistance](healthkit/hkglasseslensspecification/nearpupillarydistance.md)
- [prism](healthkit/hkglasseslensspecification/prism.md)