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  "documentType" : "symbol",
  "framework" : "HealthKit",
  "identifier" : "/documentation/HealthKit/HKSamplePredicate/visionPrescription(_:)",
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  "title" : "visionPrescription(_:)"
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# visionPrescription(_:)

Returns a predicate that matches prescription samples.

```
static func visionPrescription(_ predicate: NSPredicate? = nil) -> HKSamplePredicate<HKVisionPrescription>
```

## Parameters

`predicate`

A predicate that further filters the matching prescriptions.

## Discussion

Use this method to create a predicate that matches vision prescriptions.

```swift
// Create a predicate that matches samples stored today.
let end = Date()
let start = Calendar.current.startOfDay(for: Date())
let datePredicate = HKQuery.predicateForSamples(withStart: start, end: end)

// Create a predicate that matches vision prescriptions samples stored today.
let predicate = HKSamplePredicate.visionPrescription(datePredicate)
```

---

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