Do I need to include the clause: “…even if wearing glasses” and “even if using a hearing aid”?
In a few countries we have learned that hearing aids are non-existent. In these cases it would be appropriate to omit the clause “…even if using a hearing aid.”
On the other hand, to indiscriminately omit the clause “…even if wearing glasses.” would grossly inflate disability prevalence since anyone who uses glasses or lenses to correct a visual impairment would answer affirmatively (many with serious difficulties). Only in places where glasses are close to non-existent should the clause be removed.
If time and space permit, it may be preferable to split the two sensory questions, as in the Extended Set:
Do you wear glasses?
If Yes: Do you have difficulty seeing even if wearing your glasses?
If No: Do you have difficulty seeing?