Some definitions describe a Companion as one who “saw” the Prophet ﷺ. The term liqāʾ, meeting, is more inclusive, since a person without eyesight may meet someone without visually seeing them. A sight-only formula could wrongly exclude genuine Companions who were blind.
Example: ʿAbd Allāh ibn Umm Maktūm was blind. His lack of visual sight cannot nullify the fact that he met the Messenger ﷺ in faith. The operative fact is the encounter, not the exercise of physical eyesight.
Technical definitions should therefore use language covering all qualifying cases. Ability to see and attainment of Prophetic companionship are not interchangeable.