Combine crumbs, margarine and sugar and pat into a 9 x 13 inch dish. Beat eggs, powdered sugar and cream cheese until light and fluffy. Spread on top of prepared crumb crust. Bake at 350 degrees for 20 minutes. Cool. Combine lemon juice and blueberry pie filling and spread over cooled crust. Spread whipped topping over blueberry layer. Chill. Cut into squares. To use Fresh Blueberries: use 3 cups fresh blueberries, 1/2 cup sugar, 1 Tablespoon lemon juice, 2 Tablespoons cornstarch. Combine sugar and cornstarch, add lemon juice and blueberries. Stir gently over low heat until berries are hot and sugar has dissolved and mixture becomes clear and transparent. Cool and use in place of pie filling.