diff --git a/exporters/metrics/ocagent/src/main/java/io/opencensus/exporter/metrics/ocagent/MetricsProtoUtils.java b/exporters/metrics/ocagent/src/main/java/io/opencensus/exporter/metrics/ocagent/MetricsProtoUtils.java
index ecfba54243..a2b9aa929b 100644
--- a/exporters/metrics/ocagent/src/main/java/io/opencensus/exporter/metrics/ocagent/MetricsProtoUtils.java
+++ b/exporters/metrics/ocagent/src/main/java/io/opencensus/exporter/metrics/ocagent/MetricsProtoUtils.java
@@ -37,15 +37,18 @@
 /** Utilities for converting Metrics APIs in OpenCensus Java to OpenCensus Metrics Proto. */
 final class MetricsProtoUtils {
 
-  // TODO(songya): determine if we should make the optimization on not sending already-existed
-  // MetricDescriptors.
   static Metric toMetricProto(
       io.opencensus.metrics.export.Metric metric,
-      @Nullable io.opencensus.resource.Resource resource) {
+      @Nullable io.opencensus.resource.Resource resource,
+      boolean alreadySent) {
     Metric.Builder builder = Metric.newBuilder();
-    builder.setMetricDescriptor(toMetricDescriptorProto(metric.getMetricDescriptor()));
+    if (alreadySent) {
+      builder.setName(metric.getMetricDescriptor().getName());
+    } else {
+      builder.setMetricDescriptor(toMetricDescriptorProto(metric.getMetricDescriptor()));
+    }
     for (io.opencensus.metrics.export.TimeSeries timeSeries : metric.getTimeSeriesList()) {
-      builder.addTimeseries(toTimeSeriesProto(timeSeries));
+      builder.addTimeseries(toTimeSeriesProto(timeSeries, alreadySent));
     }
     if (resource != null) {
       builder.setResource(toResourceProto(resource));
@@ -104,7 +107,8 @@ private static Resource toResourceProto(io.opencensus.resource.Resource resource
     return builder.build();
   }
 
-  private static TimeSeries toTimeSeriesProto(io.opencensus.metrics.export.TimeSeries timeSeries) {
+  private static TimeSeries toTimeSeriesProto(
+      io.opencensus.metrics.export.TimeSeries timeSeries, boolean alreadySent) {
     TimeSeries.Builder builder = TimeSeries.newBuilder();
     if (timeSeries.getStartTimestamp() != null) {
       builder.setStartTimestamp(toTimestampProto(timeSeries.getStartTimestamp()));
@@ -113,7 +117,7 @@ private static TimeSeries toTimeSeriesProto(io.opencensus.metrics.export.TimeSer
       builder.addLabelValues(toLabelValueProto(labelValue));
     }
     for (io.opencensus.metrics.export.Point point : timeSeries.getPoints()) {
-      builder.addPoints(toPointProto(point));
+      builder.addPoints(toPointProto(point, alreadySent));
     }
     return builder.build();
   }
@@ -128,7 +132,8 @@ private static LabelValue toLabelValueProto(io.opencensus.metrics.LabelValue lab
     return builder.build();
   }
 
-  private static Point toPointProto(io.opencensus.metrics.export.Point point) {
+  private static Point toPointProto(
+      io.opencensus.metrics.export.Point point, final boolean alreadySent) {
     final Point.Builder builder = Point.newBuilder();
     builder.setTimestamp(toTimestampProto(point.getTimestamp()));
     point
@@ -151,7 +156,7 @@ public Void apply(Long arg) {
             new Function<Distribution, Void>() {
               @Override
               public Void apply(Distribution arg) {
-                builder.setDistributionValue(toDistributionProto(arg));
+                builder.setDistributionValue(toDistributionProto(arg, alreadySent));
                 return null;
               }
             },
@@ -167,13 +172,13 @@ public Void apply(Summary arg) {
   }
 
   private static DistributionValue toDistributionProto(
-      io.opencensus.metrics.export.Distribution distribution) {
+      io.opencensus.metrics.export.Distribution distribution, boolean alreadySent) {
     DistributionValue.Builder builder = DistributionValue.newBuilder();
     builder
         .setSum(distribution.getSum())
         .setCount(distribution.getCount())
         .setSumOfSquaredDeviation(distribution.getSumOfSquaredDeviations());
-    if (distribution.getBucketOptions() != null) {
+    if (!alreadySent && distribution.getBucketOptions() != null) {
       builder.setBucketOptions(toBucketOptionsProto(distribution.getBucketOptions()));
     }
     for (io.opencensus.metrics.export.Distribution.Bucket bucket : distribution.getBuckets()) {
@@ -182,8 +187,6 @@ private static DistributionValue toDistributionProto(
     return builder.build();
   }
 
-  // TODO(songya): determine if we should make the optimization on not sending already-existed
-  // BucketOptions.
   private static DistributionValue.BucketOptions toBucketOptionsProto(
       Distribution.BucketOptions bucketOptions) {
     final DistributionValue.BucketOptions.Builder builder =
diff --git a/exporters/metrics/ocagent/src/test/java/io/opencensus/exporter/metrics/ocagent/MetricsProtoUtilsTests.java b/exporters/metrics/ocagent/src/test/java/io/opencensus/exporter/metrics/ocagent/MetricsProtoUtilsTests.java
index cbf0121526..c74820bb8b 100644
--- a/exporters/metrics/ocagent/src/test/java/io/opencensus/exporter/metrics/ocagent/MetricsProtoUtilsTests.java
+++ b/exporters/metrics/ocagent/src/test/java/io/opencensus/exporter/metrics/ocagent/MetricsProtoUtilsTests.java
@@ -109,7 +109,7 @@ public class MetricsProtoUtilsTests {
       Resource.create("env", Collections.<String, String>singletonMap("env_key", "env_val"));
 
   @Test
-  public void toMetricProto_Distribution() {
+  public void toMetricProto_Distribution_NotSent() {
     Metric metric = Metric.create(DESCRIPTOR_1, Collections.singletonList(TIME_SERIES_1));
     io.opencensus.proto.metrics.v1.Metric expected =
         io.opencensus.proto.metrics.v1.Metric.newBuilder()
@@ -178,12 +178,61 @@ public void toMetricProto_Distribution() {
                     .build())
             .build();
     io.opencensus.proto.metrics.v1.Metric actual =
-        MetricsProtoUtils.toMetricProto(metric, RESOURCE);
+        MetricsProtoUtils.toMetricProto(metric, RESOURCE, false);
     assertThat(actual).isEqualTo(expected);
   }
 
   @Test
-  public void toMetricProto_Summary() {
+  public void toMetricProto_Distribution_AlreadySent() {
+    Metric metric = Metric.create(DESCRIPTOR_1, Collections.singletonList(TIME_SERIES_1));
+    io.opencensus.proto.metrics.v1.Metric expected =
+        io.opencensus.proto.metrics.v1.Metric.newBuilder()
+            .setName(METRIC_NAME_1) // Send metric name instead of whole metric descriptor.
+            .addTimeseries(
+                io.opencensus.proto.metrics.v1.TimeSeries.newBuilder()
+                    .setStartTimestamp(MetricsProtoUtils.toTimestampProto(TIMESTAMP_4))
+                    .addLabelValues(
+                        io.opencensus.proto.metrics.v1.LabelValue.newBuilder()
+                            .setHasValue(true)
+                            .setValue(VALUE_1.getValue())
+                            .build())
+                    .addPoints(
+                        io.opencensus.proto.metrics.v1.Point.newBuilder()
+                            .setTimestamp(MetricsProtoUtils.toTimestampProto(TIMESTAMP_2))
+                            .setDistributionValue(
+                                DistributionValue.newBuilder()
+                                    .setCount(5)
+                                    .setSum(24.0)
+                                    .setSumOfSquaredDeviation(321.5)
+                                    // No need to send BucketOptions again.
+                                    .addBuckets(
+                                        DistributionValue.Bucket.newBuilder().setCount(2).build())
+                                    .addBuckets(
+                                        DistributionValue.Bucket.newBuilder().setCount(1).build())
+                                    .addBuckets(
+                                        DistributionValue.Bucket.newBuilder()
+                                            .setCount(2)
+                                            .setExemplar(
+                                                DistributionValue.Exemplar.newBuilder()
+                                                    .setTimestamp(
+                                                        MetricsProtoUtils.toTimestampProto(
+                                                            TIMESTAMP_1))
+                                                    .setValue(11)
+                                                    .build())
+                                            .build())
+                                    .addBuckets(
+                                        DistributionValue.Bucket.newBuilder().setCount(0).build())
+                                    .build())
+                            .build())
+                    .build())
+            .build();
+    io.opencensus.proto.metrics.v1.Metric actual =
+        MetricsProtoUtils.toMetricProto(metric, null, true);
+    assertThat(actual).isEqualTo(expected);
+  }
+
+  @Test
+  public void toMetricProto_Summary_NotSent() {
     Metric metric = Metric.create(DESCRIPTOR_2, Collections.singletonList(TIME_SERIES_2));
     io.opencensus.proto.metrics.v1.Metric expected =
         io.opencensus.proto.metrics.v1.Metric.newBuilder()
@@ -237,7 +286,8 @@ public void toMetricProto_Summary() {
                             .build())
                     .build())
             .build();
-    io.opencensus.proto.metrics.v1.Metric actual = MetricsProtoUtils.toMetricProto(metric, null);
+    io.opencensus.proto.metrics.v1.Metric actual =
+        MetricsProtoUtils.toMetricProto(metric, null, false);
     assertThat(actual).isEqualTo(expected);
   }
 }