---
title: diameter
framework: healthkit
role: symbol
role_heading: Instance Property
path: healthkit/hkcontactslensspecification/diameter
---

# diameter

Part of the contact’s fit, it measures the diameter of the lens, measured in mm.

## Declaration

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

## Discussion

Discussion The property’s range is 9 to 15 mm.

## See Also

### Accessing the specification’s data

- [baseCurve](healthkit/hkcontactslensspecification/basecurve.md)