---
title: HKLensSpecification
framework: healthkit
role: symbol
role_heading: Class
path: healthkit/hklensspecification
---

# HKLensSpecification

An abstract superclass for lens specifications.

## Declaration

```swift
class HKLensSpecification
```

## Overview

Overview Don’t instantiate this class directly. Instead, use one of its concrete subclasses: HKGlassesLensSpecification or HKContactsLensSpecification.

## Topics

### Accessing lens specification data

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

## Relationships

### Inherits From

- [NSObject](objectivec/nsobject-swift.class.md)

### Inherited By

- [HKContactsLensSpecification](healthkit/hkcontactslensspecification.md)
- [HKGlassesLensSpecification](healthkit/hkglasseslensspecification.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Vision prescriptions

- [HKVisionPrescription](healthkit/hkvisionprescription.md)
- [HKGlassesPrescription](healthkit/hkglassesprescription.md)
- [HKContactsPrescription](healthkit/hkcontactsprescription.md)
- [HKGlassesLensSpecification](healthkit/hkglasseslensspecification.md)
- [HKContactsLensSpecification](healthkit/hkcontactslensspecification.md)
- [HKVisionPrism](healthkit/hkvisionprism.md)
- [HKPrescriptionType](healthkit/hkprescriptiontype.md)