C.8.25.14 Ophthalmic Axial Measurements Module

Table C.8.25.14-1 defines the Attributes used to encode axial measurements of the eye made by an axial measurements device. This is typically done for both eyes, but may be for just one.

Table C.8.25.14-1OPHTHALMIC AXIAL MEASUREMENTS MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Ophthalmic Axial Measurements Device Type (0022,1009) 1 Describes the type of ophthalmic axial measurement acquisition device. Defined Terms: ULTRASOUND OPTICAL
Ophthalmic Ultrasound Method Code Sequence (0022,1044) 1C The method used for obtaining axial measurements of the eye. Only a single Item shall be included in this sequence. Required if Ophthalmic Axial Measurements Device Type (0022,1009) is ULTRASOUND.
>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4230
Anterior Chamber Depth Definition Code Sequence (0022,1125) 3 The definition of anterior chamber depth for this instrument. Only a single Item is permitted in this sequence.
>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4239
Ophthalmic Axial Measurements Right Eye Sequence (0022,1007) 1C Axial measurements of a patient’s right eye. Only a single Item shall be included in this sequence. Required if the right eye is measured.
>Include ' Ophthalmic Axial Measurements Macro' Table C.8.25.14-2
>Include ' Ophthalmic Axial Measurements Selected Macro' Table C.8.25.14-5
Ophthalmic Axial Measurements Left Eye Sequence (0022,1008) 1C Axial measurements of a patient’s left eye. Only a single Item shall be included in this sequence. Required if the left eye is measured.
>Include ' Ophthalmic Axial Measurements Macro' Table C.8.25.14-2
>Include ' Ophthalmic Axial Measurements Selected Macro' Table C.8.25.14-5

C.8.25.14.1 Ophthalmic Axial Measurements Macro

Table C.8.25.14-2 describes the attributes for the Ophthalmic Axial Measurements Macro.

Table C.8.25.14-2 OPHTHALMIC AXIAL MEASUREMENTS MACRO

Attribute Name Tag Type Attribute Description
Lens Status Code Sequence (0022,1024) 1 Lens status of the eye. See section C.8.25.14.1.1.1 for further explanation. Only a single Item shall be included in this sequence.
>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4231
Lens Status Description (0022,1065) 3 A free form text description of the Lens Status (0022,1024).
Vitreous Status Code Sequence (0022,1025) 1 Status of the vitreous cavity. See section C.8.25.14.1.1.2 for further explanation. Only a single Item shall be included in this sequence.
>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4232
Vitreous Status Description (0022,1066) 3 A free form text description of Vitreous Status (0022,1025).
Pupil Dilated (0022,000D) 2 Whether or not the patient’s pupils were pharmacologically dilated for this acquisition Enumerated Values: YES NO If this tag is empty, no information is available.
Degree of Dilation (0022,000E) 2C The degree of the dilation in mm. Required if the value of Pupil Dilated (0022,000D) is YES.
Mydriatic Agent Sequence (0022,0058) 2C Information about the agent administered. Zero or more Items shall be included in this sequence. Note: An empty sequence indicates that an agent was used for dilation, but the name was not entered. Required if the value of Pupil Dilated (0022,000D) is YES.
>Mydriatic Agent Code Sequence (0022,001C) 1 The actual agent administered to dilate the pupil. Only a single Item shall be included in this sequence.
>>Include ‘Code Sequence Macro’ Table 8.8-1 Baseline Context ID is 4208.
>Mydriatic Agent Concentration (0022,004E) 3 The concentration of the agent.
>Mydriatic Agent Concentration Units Sequence (0022,0042) 1C Units of measure for the Mydriatic Agent Concentration. Only a single Item shall be included in this sequence. Required if Mydriatic Agent Concentration (0022,004E) is present.
>>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4244
Ophthalmic Axial Length Measurements Sequence (0022,1050) 1 Measurements of the axial length of a patient’s eye. One or more items shall be included in this sequence.
>Ophthalmic Axial Length Measurements Type (0022,1010) 1 Identifies whether measuring the total axial length of the patient’s eye or a segment of the eye for which a discrete measurement was obtained. Enumerated Values: TOTAL LENGTH = the total axial length was taken with one measurement LENGTH SUMMATION = a summation of segmental lengths that determine the total axial length SEGMENTAL LENGTH = a segmental axial length
>Ophthalmic Axial Length Measurements Total Length Sequence (0022,1210) 1C The axial length of a patient’s eye, in mm. One or more items shall be included in this sequence. Required if Ophthalmic Axial Length Measurements Type (0022,1010) is TOTAL LENGTH. See section C.8.25.14.1.1.4 for further explanation.
>>Ophthalmic Axial Length (0022,1019) 1 The axial length measurement acquired, in mm. The type of measurement is specified in the Ophthalmic Axial Length Measurements Type (0022,1010). See sections C.8.25.14.1.1.3 and C.8.25.14.1.1.4 for further explanation.
>>Ophthalmic Axial Length Measurement Modified (0022,1140) 1 Whether or not the clinician intervened to modify the output of the device. For example by forcing it to select a different peak in the display. Enumerated Values: YES NO
>>Referenced Ophthalmic Axial Length Measurement QC Image Sequence (0022,1330) 1 Reference to the quality control image associated with this measurement. Only a single Item shall be included in this sequence. See section C.8.25.14.1.1.6 for further explanation.
>>>Include ‘Ophthalmic Axial Measurements Quality Image SOP Instance Reference Macro’ Table C.8.25.16-6
>>Include ‘Ophthalmic Axial Measurements Related Information Macro’ Table C.8.25.14-4
>Ophthalmic Axial Length Measurements Length Summation Sequence (0022,1212) 1C Axial length of a patient’s eye, in mm, when it is calculated by summation of multiple segmental axial length measurements. One or more items shall be included in this sequence. Required if Ophthalmic Axial Length Measurements Type (0022,1010) is LENGTH SUMMATION. See section C.8.25.14.1.1.4 for further explanation.
>>Ophthalmic Axial Length (0022,1019) 1 The axial length measurement acquired, in mm. The type of measurement is specified in the Ophthalmic Axial Length Measurements Type (0022,1010). See sections C.8.25.14.1.1.3 and C.8.25.14.1.1.4 for further explanation.
>>Ophthalmic Axial Length Measurement Modified (0022,1140) 1 Whether or not the clinician intervened to modify the output of the device. For example by forcing it to select a different peak in the display. Enumerated Values: YES NO
>>Referenced Ophthalmic Axial Length Measurement QC Image Sequence (0022,1330) 1 Reference to the quality control image associated with this measurement. Only a single Item shall be included in this sequence. See section C.8.25.14.1.1.6 for further explanation.
>>>Include ‘Ophthalmic Axial Measurements Quality Image SOP Instance Reference Macro’ Table C.8.25.16-6
>>Ophthalmic Axial Length Measurements Segmental Length Sequence (0022,1211) 1 Segmental axial length measurements of a patient’s eye that contribute to an aggregate axial length measurement. One or more items shall be included in this sequence. See section C.8.25.14.1.1.4 for further explanation.
>>>Include 'Ophthalmic Axial Length Segmental Measurements Macro' Table C.8.25.14-3
>Ophthalmic Axial Length Measurements Segmental Length Sequence (0022,1211) 1C Segmental axial length measurement of a patient’s eye. Only a single Item shall be included in this sequence. Required if Ophthalmic Axial Length Measurements Type (0022,1010) is SEGMENTAL LENGTH. See section C.8.25.14.1.1.4 for further explanation.
>>Include 'Ophthalmic Axial Length Segmental Measurements Macro' Table C.8.25.14-3

C.8.25.14.1.1 Ophthalmic Axial Measurements Macro Attribute Descriptions

C.8.25.14.1.1.1 Lens Status Code Sequence

Lens Status Code Sequence (0022,1024) refers to either the natural lens of the eye (phakic), or various types of lens implants inserted in cataract surgery, or lack of a lens in the eye (aphakic).

C.8.25.14.1.1.2 Vitreous Status Code Sequence

Vitreous Status Code Sequence (0022,1025) refers to either the natural status of the vitreous cavity (vitreous only) or to various possible states after vitreous surgery.

C.8.25.14.1.1.3 Ophthalmic Axial Length

If Ophthalmic Axial Measurements Device Type (0022,1009) is ULTRASOUND, the Ophthalmic Axial Length (0022,1019) measurement is taken from the anterior vertex of the cornea to the anterior surface of the retina (internal limiting membrane).

If Ophthalmic Axial Measurements Device Type (0022,1009) is OPTICAL, the Ophthalmic Axial Length (0022,1019) measurement is taken from the anterior vertex of the cornea to the level of the photoreceptors in the retina and compensated to adjust for the thickness of the retina to mimic the ultrasound technique.

This difference is an inherent property of the measurement method. Since optical devices measure to retinal pigment epithelium and ultrasound devices measure to internal limiting membrane, the difference must be subtracted to obtain comparable results for use in intraocular lens calculation formulas. The difference is the thickness of the retina, which has been determined empirically and varies with the axial length of the eye.

The intent is to measure along the patient’s visual axis.

C.8.25.14.1.1.4 Ophthalmic Axial Length Measurements Segment Name Code Sequence

When the acquisition device type is ultrasound, the Ophthalmic Axial Length (0022,1019) may represent distance calculated using a single time value and an average presumed velocity for the entire eye. Alternatively it may represent the sum of multiple segmental axial length measurements with each distance value calculated using a different time value and a presumed velocity specific to that segment of the eye.

When the acquisition device type is optical, the whole length can be measured instead of measuring and summing up different segments of the eye. Nevertheless, optical axial measurement devices can also measure segments of the eye independently (e.g. the Anterior Chamber depth).

Each segment of the eye that is measured shall be identified by the Ophthalmic Axial Length Measurements Segment Name Code Sequence (0022,1101).

C.8.25.14.1.1.5 Observer Type

For attribute Observer Type (0040,A084), Ultrasound axial length measurement devices take many measurements in rapid sequence. The machine can be set to select a good quality measurement automatically, or it can be set so that the user presses a footswitch when he/she sees a quality measurement based on the graphical display.

C.8.25.14.1.1.6 Referenced Ophthalmic Axial Length Measurement QC Image Sequence

The attribute Referenced Ophthalmic Axial Length Measurement QC Image Sequence (0022,1330) references a quality control image that is a secondary capture of the presentation of a one dimensional waveform produced when performing ophthalmic axial measurements. It is acquired by the modality creating the ophthalmic axial measurements. The purpose of these images is to judge the quality of an axial length measurement for use in calculating the power of intraocular lens to place in a patient’s eye in cataract surgery. The image is used for quality control and not for diagnostic purposes. See PS3.17.

The SOP Instance for the quality control image will meet the following requirements:

Note: The frame number is the recommended value for the label.

The attribute Burned In Annotation (0028,0301) defines whether patient demographics have been burned into the image. This attribute does not prohibit non-demographic burned in annotation, such as position of gates, for image or waveform annotations that are very important to a user. Such annotations are expected to be conveyed and displayed.

C.8.25.14.2 Ophthalmic Axial Length Segmental Measurements Macro

Table C.8.25.14-3 describes the attributes for the Ophthalmic Axial Length Segmental Measurements Macro.

Table C.8.25.14-3 OPHTHALMIC AXIAL LENGTH SEGMENTAL MEASUREMENTS MACRO

Attribute Name Tag Type Attribute Description
Ophthalmic Axial Length (0022,1019) 1 The axial length measurement, in mm. The type of measurement is specified in the Ophthalmic Axial Length Measurements Type (0022,1010). See sections C.8.25.14.1.1.3 and C.8.25.14.1.1.4 for further explanation.
Ophthalmic Axial Length Measurement Modified (0022,1140) 1 Whether or not the clinician intervened to modify the output of the device. For example by forcing it to select a different peak in the display. Enumerated Values: YES NO
Ophthalmic Axial Length Measurements Segment Name Code Sequence (0022,1101) 1 The name of the segment measured. See section C.8.25.14.1.1.4 for further explanation. Only a single Item shall be included in this sequence.
>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4233
Include ‘Ophthalmic Axial Measurements Related Information Macro’ Table C.8.25.14-4

C.8.25.14.3 Ophthalmic Axial Measurements Related Information Macro

Table C.8.25.14-4 describes the attributes for the Ophthalmic Axial Measurements Related Information Macro.

Table C.8.25.14-4 OPHTHALMIC AXIAL MEASUREMENTS RELATED INFORMATION MACRO

Attribute Name Tag Type Attribute Description
Ultrasound Ophthalmic Axial Length Measurements Sequence (0022,1220) 1C Related information about an axial length measurement being performed on an ultrasound device. Only a single Item shall be included in this sequence. Required if Ophthalmic Axial Measurements Device Type (0022,1009) is ULTRASOUND.
>Ophthalmic Axial Length Velocity (0022,1059) 1 The sound velocity used in calculating the Ophthalmic Axial Length Measurement Value (0022,1019), in m/sec.
>Observer Type (0040,A084) 1 Method used to select which acquired axial length measurement values are kept. Enumerated Values: PSN = Person; manually selected DEV = Device; automatically selected See section C.8.25.14.1.1.5 for further explanation.
>Ophthalmic Axial Length Data Source Code Sequence (0022,1150) 1 Source of the value recorded in Ophthalmic Axial Length (0022,1019). Only a single Item shall be included in this sequence.
>>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4240
>Ophthalmic Axial Length Data Source Description (0022,1159) 3 A free text description of the axial length measurement data source.
Optical Ophthalmic Axial Length Measurements Sequence (0022,1225) 1C Related information about an axial length measurement being performed on an optical device. Only a single Item shall be included in this sequence. Required if Ophthalmic Axial Measurements Device Type (0022,1009) is OPTICAL.
>Signal to Noise Ratio (0022,1155) 1C The ratio of signal power to the background noise power (P signal/ P noise). Required if Ophthalmic Axial Length Measurements Type (0022,1010) is TOTAL LENGTH. May be present otherwise.
>Ophthalmic Axial Length Data Source Code Sequence (0022,1150) 1 The source of the value in Ophthalmic Axial Length (0022,1019). Only a single Item shall be included in this sequence.
>>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4240
>Ophthalmic Axial Length Data Source Description (0022,1159) 3 A free text description of the axial length measurement data source.

C.8.25.14.4 Ophthalmic Axial Measurements Selected Macro

Table C.8.25.14-5 describes the attributes for the Ophthalmic Axial Measurements Selected Macro. These are the attributes of the Ophthalmic Axial Length (0022,1019) selected for use in IOL calculations.

Table C.8.25.14-5 OPHTHALMIC AXIAL MEASUREMENTS SELECTED MACRO

Attribute Name Tag Type Attribute Description
Ultrasound Selected Ophthalmic Axial Length Sequence (0022,1230) 1C Information related to the selected axial length measurement of the patient’s eye when acquired on an ultrasound device. Only a single Item shall be included in this sequence. Required if Ophthalmic Axial Measurements Device Type (0022,1009) is ULTRASOUND.
>Ophthalmic Axial Length (0022,1019) 1 The axial length measurement, in mm. The type of measurement is specified in the Ophthalmic Axial Length Measurements Type (0022,1010). See sections and C.8.25.14.1.1.4 for further explanation.
>Ophthalmic Axial Length Selection Method Code Sequence (0022,1250) 1 Method used to derive the value recorded in Ophthalmic Axial Length (0022,1019). Only a single Item shall be included in this sequence.
>>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4241
>Referenced Ophthalmic Axial Length Measurement QC Image Sequence (0022,1330) 1 References to the quality control image associated with this measurement. Only a single Item shall be included in this sequence. See section C.8.25.14.1.1.6 for further explanation.
>> Include ‘Ophthalmic Axial Measurements Quality Image SOP Instance Reference Macro’ Table C.8.25.16-6
>Ophthalmic Axial Length Quality Metric Sequence (0022,1262) 1 Information about the quality metric applied to Ophthalmic Axial Length (0022,1019). Only a single Item shall be included in this sequence.
>>Include ‘Ophthalmic Axial Length Quality Metric Macro’ Table C.8.25.14-6
>Selected Segmental Ophthalmic Axial Length Sequence (0022,1257) 1C Segmental axial length measurements of a patient’s eye that are summed to derive a total axial length for the eye. One or more items shall be included in this sequence. Required if Ophthalmic Axial Length Measurements Type (0022,1010) is LENGTH SUMMATION.
>>Ophthalmic Axial Length (0022,1019) 1 The axial length measurement, in mm. The type of measurement is specified in the Ophthalmic Axial Length Measurements Type (0022,1010). See sections C.8.25.14.1.1.3 and C.8.25.14.1.4 for further explanation.
>>Ophthalmic Axial Length Measurements Segment Name Code Sequence (0022,1101) 1 Name of the segment measured. See section C.8.25.14.1.1.4 for further explanation. Only a single Item shall be included in this sequence.
>>>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4233
Optical Selected Ophthalmic Axial Length Sequence (0022,1255) 1C Information related to the selected axial length measurement(s) of the patient’s eye when acquired on an optical device. One or more items shall be included in this sequence. Required if Ophthalmic Axial Measurements Device Type (0022,1009) is OPTICAL.
>Selected Total Ophthalmic Axial Length Sequence (0022,1260) 1C Total axial length measurement selected for the patient’s eye. Required if Ophthalmic Axial Length Measurements Type (0022,1010) is TOTAL LENGTH. Only a single Item shall be included in this sequence.
>>Ophthalmic Axial Length (0022,1019) 1 The axial length measurement, in mm. The type of measurement is specified in the Ophthalmic Axial Length Measurements Type (0022,1010). See sections C.8.25.14.1.1.3 and C.8.25.14.1.1.4 for further explanation.
>>Referenced Ophthalmic Axial Length Measurement QC Image Sequence (0022,1330) 1 Reference to the quality control image associated with this measurement. Only a single Item shall be included in this sequence. See section C.8.25.14.1.1.6 for further explanation.
>>> Include ‘Ophthalmic Axial Measurements Quality Image SOP Instance Reference Macro’ Table C.8.25.16-6
>>Ophthalmic Axial Length Quality Metric Sequence (0022,1262) 1 Information about the quality metric applied to Ophthalmic Axial Length (0022,1019). Only a single Item shall be included in this sequence.
>>>Include ‘Ophthalmic Axial Length Quality Metric Macro’ Table C.8.25.14-6
>Selected Segmental Ophthalmic Axial Length Sequence (0022,1257) 1C Segmental axial length measurement(s) selected for the patient’s eye. One or more items shall be included in this sequence. Required if Ophthalmic Axial Length Measurements Type (0022,1010) is SEGMENTAL LENGTH. May be present otherwise.
>>Ophthalmic Axial Length Measurements Segment Name Code Sequence (0022,1101) 1 Name of the segment measured. See section C.8.25.14.1.1.4 for further explanation. Only a single Item shall be included in this sequence.
>>>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4233
>>Ophthalmic Axial Length (0022,1019) 1 The axial length measurement, in mm. The type of measurement is specified in the Ophthalmic Axial Length Measurements Type (0022,1010). See sections C.8.25.14.1.1.3 and C.8.25.14.1.1.4 for further explanation.
>>Referenced Ophthalmic Axial Length Measurement QC Image Sequence (0022,1330) 3 Reference to the quality control image associated with this measurement. Only a single Item is permitted in this sequence. See section C.8.25.14.1.1.6 for further explanation.
>>>Include ‘Ophthalmic Axial Measurements Quality Image SOP Instance Reference Macro’ Table C.8.25.16-6
>>Ophthalmic Axial Length Quality Metric Sequence (0022,1262) 3 Information about the quality metric applied to Ophthalmic Axial Length (0022,1019). Only a single Item is permitted in this sequence.
>>>Include ‘Ophthalmic Axial Length Quality Metric Macro’ Table C.8.25.14-6

C.8.25.14.5 Ophthalmic Axial Measurements Quality Metric Macro

Table C.8.25.14-6 describes the attributes for the Ophthalmic Axial Length Quality Metric Macro.

Table C.8.25.14-6 OPHTHALMIC AXIAL LENGTH QUALITY METRIC MACRO

Attribute Name Tag Type Attribute Description
Concept Name Code Sequence (0040,A043) 1 Type of metric used to evaluate the quality of the ophthalmic axial length. Only a single Item shall be included in this sequence.
>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 4243
Numeric Value (0040,A30A) 1 Value for quality metric applied to axial length values.
Measurement Units Code Sequence (0040,08EA) 1 Units of Numeric Value (0040,A30A). Only a single Item shall be included in this sequence.
>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID is 82.