You can use the relationship to filter your value list to show only the related values.
For more on this, look up "Example of a value list that includes only related field values" in the filemaker help file.
One issue to look out for: This approach will restrict your list to just those students who already have a record in the special needs equipment table. That may cause a problem when you add a student's equipment data for the first time.
If you have a field in the main table that identifies each student with special needs, you can use it in a calculation to restrict your value list.
Let's say you have a text field that reads "special needs" for each such student.
Your calculation could read:
If ( specialFld = "special needs", studentnamefield , "" )
If you specify this field as your value source in a value list, only those students that have "special needs" in SpecialFld will appear in the value list.
Final design comment: Beware of using name fields to relate tables in a database. You could have two students with the same name and a student's name could change. Either event will cause problems in a database that relates records by name. Use an student ID number instead to avoid this.