Hi Lars, and thank you for taking a lead in progressing this archetype!
We’re preparing for a likely order for functionality to support outpatient intravitreal injection therapy, and visual acuity is one of the archetypes we’ll need for this purpose. So I’d like to participate in this work.
I agree with several of your proposed changes, but one change I’m not enthusiastic about is splitting the magnitude and unit from the DV_QUANTITY data type into two separate elements. This is problematic both from the generic openEHR POV and from an implementation POV:
- Generically, in openEHR the magnitude and units of a quantity are expected to be found at their assigned paths within a single instance of DV_QUANTITY, and splitting them up into different elements would complicate querying.
- When implementing solutions using low code tools, these tools expect quantities to be expressed as DV_QUANTITY data types as specified, and trying to split them into separate archetyped elements would complicate implementations.
Regarding the issue of units, I saw your proposal for adding these units to UCUM, and ideally this would be the way to get these units represented. However, my impression is that UCUM isn’t staffed to handle requests like this, even less than openEHR is. We recently had a discussion about this issue here. One thing we could do to handle the issue though is to add our own UCUM-compatible notation to our own units file which is used by Archetype Designer. See for example this commit to add some units variations used in audiology.