I think you want to use two fields: a Text field named Eye Response, and a Calculation field with the above formula and the result type set to Number..
The case statement work from top to bottoma bit like nested ifs. The syntax is:=
Test 1; Result 1;
Test 2; Result 2;
Test 3; Result 3;
Unlike if statements, as soon as a test is true then the result is given and the statement drops out and no other part of the statement is tested.
For your problem you should have a drop down on the TEXT field 'Eye Response' from a value list with
Spontaneously, To Speech, To Pain and None.
You then need another field for your case statement called something like Response Result and define it as a calculation
Eye Response ="Spontaneously"; 4;
Eye Response="To Speech"; 3;
Eye Response="To Pain"; 2;
That should sort you out.
Thank you so much. It worked well. Mary