diff --git a/src/ol/layer/layer.js b/src/ol/layer/layer.js
index b9e7cb6ab5..55850bafb5 100644
--- a/src/ol/layer/layer.js
+++ b/src/ol/layer/layer.js
@@ -57,15 +57,10 @@ ol.layer.Layer.prototype.getLayersArray = function(opt_array) {
 /**
  * @inheritDoc
  */
-ol.layer.Layer.prototype.getLayerStatesArray = function(opt_obj) {
-  var obj = (goog.isDef(opt_obj)) ? opt_obj : {
-    layers: [],
-    layerStates: []
-  };
-  goog.asserts.assert(obj.layers.length === obj.layerStates.length);
-  obj.layers.push(this);
-  obj.layerStates.push(this.getLayerState());
-  return obj;
+ol.layer.Layer.prototype.getLayerStatesArray = function(opt_states) {
+  var states = (goog.isDef(opt_states)) ? opt_states : [];
+  states.push(this.getLayerState());
+  return states;
 };
 
 
diff --git a/src/ol/layer/layerbase.js b/src/ol/layer/layerbase.js
index 160fd04b7d..a55b2b9aa4 100644
--- a/src/ol/layer/layerbase.js
+++ b/src/ol/layer/layerbase.js
@@ -150,14 +150,9 @@ ol.layer.Base.prototype.getLayersArray = goog.abstractMethod;
 
 
 /**
- * @param {{
- *     layers: Array.<ol.layer.Layer>,
- *     layerStates: Array.<ol.layer.LayerState>}=} opt_obj Object that store
- *     both the layers and the layerStates (to be modified in place).
- * @return {{
- *     layers: Array.<ol.layer.Layer>,
- *     layerStates: Array.<ol.layer.LayerState>}} Object that store both the
- *     layers and the layerStates.
+ * @param {Array.<ol.layer.LayerState>=} opt_states Optional list of layer
+ *     states (to be modified in place).
+ * @return {Array.<ol.layer.LayerState>} List of layer states.
  */
 ol.layer.Base.prototype.getLayerStatesArray = goog.abstractMethod;
 
diff --git a/src/ol/layer/layergroup.js b/src/ol/layer/layergroup.js
index 390cff2c0b..d814571de3 100644
--- a/src/ol/layer/layergroup.js
+++ b/src/ol/layer/layergroup.js
@@ -183,22 +183,19 @@ ol.layer.Group.prototype.getLayersArray = function(opt_array) {
 /**
  * @inheritDoc
  */
-ol.layer.Group.prototype.getLayerStatesArray = function(opt_obj) {
-  var obj = (goog.isDef(opt_obj)) ? opt_obj : {
-    layers: [],
-    layerStates: []
-  };
-  goog.asserts.assert(obj.layers.length === obj.layerStates.length);
-  var pos = obj.layers.length;
+ol.layer.Group.prototype.getLayerStatesArray = function(opt_states) {
+  var states = (goog.isDef(opt_states)) ? opt_states : [];
+
+  var pos = states.length;
 
   this.getLayers().forEach(function(layer) {
-    layer.getLayerStatesArray(obj);
+    layer.getLayerStatesArray(states);
   });
 
   var ownLayerState = this.getLayerState();
   var i, ii, layerState;
-  for (i = pos, ii = obj.layerStates.length; i < ii; i++) {
-    layerState = obj.layerStates[i];
+  for (i = pos, ii = states.length; i < ii; i++) {
+    layerState = states[i];
     layerState.brightness = goog.math.clamp(
         layerState.brightness + ownLayerState.brightness, -1, 1);
     layerState.contrast *= ownLayerState.contrast;
@@ -212,7 +209,7 @@ ol.layer.Group.prototype.getLayerStatesArray = function(opt_obj) {
         layerState.minResolution, ownLayerState.minResolution);
   }
 
-  return obj;
+  return states;
 };
 
 
diff --git a/src/ol/map.js b/src/ol/map.js
index 5463e5174a..9c5d171858 100644
--- a/src/ol/map.js
+++ b/src/ol/map.js
@@ -1207,14 +1207,10 @@ ol.Map.prototype.renderFrame_ = function(time) {
   if (goog.isDef(size) && hasArea(size) &&
       goog.isDef(view2D) && view2D.isDef()) {
     var viewHints = view.getHints();
-    var obj = this.getLayerGroup().getLayerStatesArray();
-    var layersArray = obj.layers;
-    var layerStatesArray = obj.layerStates;
+    var layerStatesArray = this.getLayerGroup().getLayerStatesArray();
     var layerStates = {};
-    var layer;
-    for (i = 0, ii = layersArray.length; i < ii; ++i) {
-      layer = layersArray[i];
-      layerStates[goog.getUid(layer)] = layerStatesArray[i];
+    for (i = 0, ii = layerStatesArray.length; i < ii; ++i) {
+      layerStates[goog.getUid(layerStatesArray[i].layer)] = layerStatesArray[i];
     }
     view2DState = view2D.getView2DState();
     frameState = /** @type {oli.FrameState} */ ({
diff --git a/src/ol/renderer/maprenderer.js b/src/ol/renderer/maprenderer.js
index 6632fc3328..f041562fe9 100644
--- a/src/ol/renderer/maprenderer.js
+++ b/src/ol/renderer/maprenderer.js
@@ -97,15 +97,12 @@ ol.renderer.Map.prototype.disposeInternal = function() {
 ol.renderer.Map.prototype.forEachFeatureAtPixel =
     function(coordinate, frameState, callback, thisArg,
         layerFilter, thisArg2) {
-  var obj = this.map_.getLayerGroup().getLayerStatesArray();
-  var layers = obj.layers;
-  var layerStates = obj.layerStates;
-  goog.asserts.assert(layers.length == layerStates.length);
-  var numLayers = layers.length;
+  var layerStates = this.map_.getLayerGroup().getLayerStatesArray();
+  var numLayers = layerStates.length;
   var i;
   for (i = numLayers - 1; i >= 0; --i) {
     var layerState = layerStates[i];
-    var layer = layers[i];
+    var layer = layerState.layer;
     if (layerState.visible && layerFilter.call(thisArg2, layer)) {
       var layerRenderer = this.getLayerRenderer(layer);
       var result = layerRenderer.forEachFeatureAtPixel(
diff --git a/test/spec/ol/layer/layergroup.test.js b/test/spec/ol/layer/layergroup.test.js
index 20650c8bb4..d28ca09773 100644
--- a/test/spec/ol/layer/layergroup.test.js
+++ b/test/spec/ol/layer/layergroup.test.js
@@ -297,19 +297,10 @@ describe('ol.layer.Group', function() {
 
   describe('#getLayerStatesArray', function() {
 
-    var layerGroup;
-    var layersArray;
-    var layerStatesArray;
-    var obj;
-
     it('returns an empty array if no layer', function() {
-      layerGroup = new ol.layer.Group();
+      var layerGroup = new ol.layer.Group();
 
-      obj = layerGroup.getLayerStatesArray();
-      layersArray = obj.layers;
-      layerStatesArray = obj.layerStates;
-      expect(layersArray).to.be.a(Array);
-      expect(layersArray.length).to.be(0);
+      var layerStatesArray = layerGroup.getLayerStatesArray();
       expect(layerStatesArray).to.be.a(Array);
       expect(layerStatesArray.length).to.be(0);
 
@@ -336,17 +327,11 @@ describe('ol.layer.Group', function() {
     });
 
     it('does not transform layerStates by default', function() {
-      layerGroup = new ol.layer.Group({
+      var layerGroup = new ol.layer.Group({
         layers: [layer1, layer2]
       });
 
-      obj = layerGroup.getLayerStatesArray();
-      layersArray = obj.layers;
-      layerStatesArray = obj.layerStates;
-      expect(layersArray).to.be.a(Array);
-      expect(layersArray.length).to.be(2);
-      expect(layersArray[0]).to.be(layer1);
-      expect(layersArray[1]).to.be(layer2);
+      var layerStatesArray = layerGroup.getLayerStatesArray();
       expect(layerStatesArray).to.be.a(Array);
       expect(layerStatesArray.length).to.be(2);
       expect(layerStatesArray[0]).to.eql(layer1.getLayerState());
@@ -364,7 +349,7 @@ describe('ol.layer.Group', function() {
     });
 
     it('transforms layerStates correctly', function() {
-      layerGroup = new ol.layer.Group({
+      var layerGroup = new ol.layer.Group({
         layers: [layer1, layer2],
         brightness: 0.5,
         contrast: 10,
@@ -376,9 +361,7 @@ describe('ol.layer.Group', function() {
         minResolution: 0.2
       });
 
-      obj = layerGroup.getLayerStatesArray();
-      layersArray = obj.layers;
-      layerStatesArray = obj.layerStates;
+      var layerStatesArray = layerGroup.getLayerStatesArray();
 
       // compare layer state to group state
       var groupState, layerState;