Question : Is there a way to restrict access to author only for one field on form

Have a form that needs one field to have edit access only by the author.  Is there a way to do this?

Answer : Is there a way to restrict access to author only for one field on form

This can be achieved by simply creating 3 fields.
First field: For others.
Computed.  HideWhen: @Ismember(@Name[CN];@USername);ThirdField)
Default formulae: SecondFieldName

SecondField: For only Author to edit.
Editable. HideWhen: !@Ismember(@Name[CN];@USername);ThirdField)

You can place the First and Second field one below the other.

Third Field: To store Author name
ComputedWhenComposed. You can hide it for all.
Formulae:
@Name([CN];@Username)

When Author opens the document in Edit mode, Author will see second field in Edit mode, while others will see the First field (in read/edit mode).
Hope it helps.