You can access objects in an object layer in one of several ways.
layer.object TableAn object layer stores each of the layer's objects in the layer.object table. Just as in the map.layer table, you can access an object through either the object's name (set from Tiled) or the object's index.
local object
object = map.layer[x].object[1] -- The first object in the layer
object = map.layer[x].object["object"] -- The object named "object" in Tiled
Object layers also provide a number of ways to iterate through each object in the layer. See the object iterator reference for more information.