---
title: HKPrismBase
framework: healthkit
role: symbol
role_heading: Enumeration
path: healthkit/hkprismbase
---

# HKPrismBase

The orientation of the prism correction, represented by the location of the prism’s base (the thickest part of the prism).

## Declaration

```swift
enum HKPrismBase
```

## Topics

### Prism Base

- [HKPrismBase.none](healthkit/hkprismbase/none.md)
- [HKPrismBase.up](healthkit/hkprismbase/up.md)
- [HKPrismBase.down](healthkit/hkprismbase/down.md)
- [HKPrismBase.in](healthkit/hkprismbase/in.md)
- [HKPrismBase.out](healthkit/hkprismbase/out.md)

### Initializers

- [init(rawValue:)](healthkit/hkprismbase/init(rawvalue:).md)

## Relationships

### Conforms To

- [BitwiseCopyable](swift/bitwisecopyable.md)
- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [RawRepresentable](swift/rawrepresentable.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Accessing lens specification data

- [eye](healthkit/hkvisionprism/eye.md)
- [HKVisionEye](healthkit/hkvisioneye.md)
- [amount](healthkit/hkvisionprism/amount.md)
- [angle](healthkit/hkvisionprism/angle.md)
- [horizontalAmount](healthkit/hkvisionprism/horizontalamount.md)
- [horizontalBase](healthkit/hkvisionprism/horizontalbase.md)
- [verticalAmount](healthkit/hkvisionprism/verticalamount.md)
- [verticalBase](healthkit/hkvisionprism/verticalbase.md)