potentially relevant for CRD in some situations.

An authorization for the provision of glasses and/or contact lenses to a patient.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

An Extension

Indicates coverage information.

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

A unique identifier assigned to this vision prescription.

Allows vision prescriptions to be distinguished and referenced.

The status of the resource instance.

This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

A code specifying the state of the resource instance.

Need to track the status of the resource as 'draft' resources may undergo further edits while 'active' resources are immutable and may only have their status changed to 'cancelled'.

The date this resource was created.

Need to record a timestamp for use by both the recipient and the issuer.

A resource reference to the person to whom the vision prescription applies.

Needed to identify the patient for whom the vision prescription has been issued.

A reference to a resource that identifies the particular occurrence of contact between patient and health care provider during which the prescription was issued.

potentially relevant for CRD in some situations.

Used in some jurisdictions to link clinical events to claim items.

The date (and perhaps time) when the prescription was written.

Jurisdictions determine the valid lifetime of a prescription. Typically vision prescriptions are valid for two years from the date written.

Need to record a timestamp for use by both the recipient and the issuer.

The healthcare professional responsible for authorizing the prescription.

Need to record the authorizing practitioner.

Contain the details of the individual lens specifications and serves as the authorization for the fullfillment by certified professionals.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Identifies the type of vision correction product which is required for the patient.

A coded concept describing the vision products.

Need to identify whether glasses or contacts.

The eye for which the lens specification applies.

May also appear as OD (oculus dexter) for the right eye and OS (oculus siniter) for the left eye.

A coded concept listing the eye codes.

Needed to identify which eye the lens specification applies to.

Lens power measured in dioptres (0.25 units).

The value is negative for near-sighted and positive for far sighted. Often insurance will not cover a lens with power between +75 and -75.

Standard lens prescription measures.

Power adjustment for astigmatism measured in dioptres (0.25 units).

Standard lens prescription measures.

Adjustment for astigmatism measured in integer degrees.

The limits are +180 and -180 degrees.

Standard lens prescription measures.

Allows for adjustment on two axis.

Standard lens prescription measures.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Amount of prism to compensate for eye alignment in fractional units.

Standard lens prescription measures.

The relative base, or reference lens edge, for the prism.

A coded concept listing the base codes.

Standard lens prescription measures.

Power adjustment for multifocal lenses measured in dioptres (0.25 units).

Standard lens prescription measures.

Contact lens power measured in dioptres (0.25 units).

Standard contact lens prescription measures.

Back curvature measured in millimetres.

Standard contact lens prescription measures.

Contact lens diameter measured in millimetres.

Standard contact lens prescription measures.

The recommended maximum wear period for the lens.

Standard contact lens prescription measures.

An authorization for the provision of glasses and/or contact lenses to a patient.

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

The base language in which the resource is written.

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

A human language.

A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

An Extension

Indicates coverage information.

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

A unique identifier assigned to this vision prescription.

Allows vision prescriptions to be distinguished and referenced.

The status of the resource instance.

This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

A code specifying the state of the resource instance.

Need to track the status of the resource as 'draft' resources may undergo further edits while 'active' resources are immutable and may only have their status changed to 'cancelled'.

The date this resource was created.

Need to record a timestamp for use by both the recipient and the issuer.

A resource reference to the person to whom the vision prescription applies.

Needed to identify the patient for whom the vision prescription has been issued.

A reference to a resource that identifies the particular occurrence of contact between patient and health care provider during which the prescription was issued.

potentially relevant for CRD in some situations.

Used in some jurisdictions to link clinical events to claim items.

The date (and perhaps time) when the prescription was written.

Jurisdictions determine the valid lifetime of a prescription. Typically vision prescriptions are valid for two years from the date written.

Need to record a timestamp for use by both the recipient and the issuer.

The healthcare professional responsible for authorizing the prescription.

Need to record the authorizing practitioner.

Contain the details of the individual lens specifications and serves as the authorization for the fullfillment by certified professionals.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Identifies the type of vision correction product which is required for the patient.

A coded concept describing the vision products.

Need to identify whether glasses or contacts.

The eye for which the lens specification applies.

May also appear as OD (oculus dexter) for the right eye and OS (oculus siniter) for the left eye.

A coded concept listing the eye codes.

Needed to identify which eye the lens specification applies to.

Lens power measured in dioptres (0.25 units).

The value is negative for near-sighted and positive for far sighted. Often insurance will not cover a lens with power between +75 and -75.

Standard lens prescription measures.

Power adjustment for astigmatism measured in dioptres (0.25 units).

Standard lens prescription measures.

Adjustment for astigmatism measured in integer degrees.

The limits are +180 and -180 degrees.

Standard lens prescription measures.

Allows for adjustment on two axis.

Standard lens prescription measures.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Amount of prism to compensate for eye alignment in fractional units.

Standard lens prescription measures.

The relative base, or reference lens edge, for the prism.

A coded concept listing the base codes.

Standard lens prescription measures.

Power adjustment for multifocal lenses measured in dioptres (0.25 units).

Standard lens prescription measures.

Contact lens power measured in dioptres (0.25 units).

Standard contact lens prescription measures.

Back curvature measured in millimetres.

Standard contact lens prescription measures.

Contact lens diameter measured in millimetres.

Standard contact lens prescription measures.

The recommended maximum wear period for the lens.

Standard contact lens prescription measures.

Special color or pattern.

Standard contact lens prescription measures.

Brand recommendations or restrictions.

Standard lens prescription measures.

Notes for special requirements such as coatings and lens materials.

Standard lens prescription measures.