C.8.25.8 Lensometry Measurements Module
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#### C.8.25.8 Lensometry Measurements Module

Table C.8.25.8-1 defines the Attributes used to capture the refractive measurements by a lensometer for spectacles. This is typically for a pair of lenses, but sometimes for just one. Sometimes a single lens is measured with an unknown laterality.

Table C.8.25.8-1. Lensometry Measurements Module Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Lens Description | (0046,0012) | 2 | A free text description of the lens and lens general comments. ### Note A common example is to identify the specific spectacles measured
Right Lens Sequence | (0046,0014) | 1C | A sequence that specifies measurements of a patient's right lens. Required if the right lens is measured. Only a single Item shall be included in this sequence. ### Note If Right Lens Sequence (0046,0014) is present, Measurement Laterality (0024,0113), if present, will have a value of R or B as appropriate.
>Include Table C.8.25.8-2 “Lensometry Measurements Macro Attributes” |
Left Lens Sequence | (0046,0015) | 1C | A sequence that specifies measurements of a patient's left lens. Required if the left lens is measured. Only a single Item shall be included in this sequence. ### Note If Left Lens Sequence (0046,0015) is present, Measurement Laterality (0024,0113), if present, will have a value of L or B as appropriate.
>Include Table C.8.25.8-2 “Lensometry Measurements Macro Attributes” |
Unspecified Laterality Lens Sequence | (0046,0016) | 1C | A sequence that specifies measurements of one lens of unknown laterality. Only a single Item shall be included in this sequence. Shall not be included if Attribute Right Lens Sequence (0046,0014) or Left Lens Sequence (0046,0015) is present. Required if a single lens of unknown laterality is measured.
>Include Table C.8.25.8-2 “Lensometry Measurements Macro Attributes” |

Table C.8.25.8-2 describes the attributes for the Lensometry Measurements Macro.

Table C.8.25.8-2. Lensometry Measurements Macro Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Sphere Power | (0046,0146) | 1 | Refractive power of the lens that is the same in all meridians, measured at distance (optical infinity), in diopters.
Include Table C.8.25.6.1-1 “Cylinder Sequence Macro Attributes” |
Add Near Sequence | (0046,0100) | 1C | A sequence that specifies refractive measurements of the lens to correct for inability to focus at near while wearing the distance prescription. Only a single item shall be included in this sequence. Required if Add Near is measured in the lens.
>Add Power | (0046,0104) | 1 | Additional power relative to the distance correction, expressed in diopters, that allows best corrected visual acuity at the defined viewing distance.
>Viewing Distance | (0046,0106) | 3 | The distance, in cm, for testing visual acuity corresponding to the value of Add Power (0046,0104) in this sequence.
Add Intermediate Sequence | (0046,0101) | 1C | A sequence that specifies refractive measurements of the lens to correct for inability to focus at intermediate distance while wearing the distance prescription. Only a single item shall be included in this sequence. Required if Add intermediate is measured in the lens.
>Add Power | (0046,0104) | 1 | Additional power relative to the distance correction, expressed in diopters, that allows best corrected visual acuity at the defined viewing distance.
>Viewing Distance | (0046,0106) | 3 | The distance, in cm, for testing visual acuity corresponding to the value of Add Power (0046,0104) in this sequence item.
Include Table C.8.25.6.2-1 “Prism Sequence Macro Attributes” |
Lens Segment Type | (0046,0038) | 3 | The type of segment of a lens containing the "add" power, as described above Enumerated Values: PROGRESSIVE NONPROGRESSIVE
Optical Transmittance | (0046,0040) | 3 | The fraction of light that passes through the measured lens optical media, in percent.
Channel Width | (0046,0042) | 3 | In a progressive lens, the width in mm of that portion of the lens where there is gradual or progressive increase in "add" power. ### Note See Attributes, Add Near Sequence (0046,0100) and Add Intermediate Sequence (0046,0101) for description of"add".

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