diff --git a/msg/SensorOpticalFlow.msg b/msg/SensorOpticalFlow.msg
index ce7e8bf08c..ed6a3cfefb 100644
--- a/msg/SensorOpticalFlow.msg
+++ b/msg/SensorOpticalFlow.msg
@@ -3,7 +3,7 @@ uint64 timestamp_sample
 
 uint32 device_id               # unique device ID for the sensor that does not change between power cycles
 
-float32[2] pixel_flow          # (radians) optical flow in radians where a positive value is produced by a RH rotation about the body axis
+float32[2] pixel_flow          # (radians) optical flow in radians where a positive value is produced by a RH rotation of the sensor about the body axis
 
 float32[3] delta_angle         # (radians) accumulated gyro radians where a positive value is produced by a RH rotation about the body axis. Set to NaN if flow sensor does not have 3-axis gyro data.
 bool delta_angle_available
diff --git a/msg/VehicleOpticalFlow.msg b/msg/VehicleOpticalFlow.msg
index 13bdb57bbf..23472b4c97 100644
--- a/msg/VehicleOpticalFlow.msg
+++ b/msg/VehicleOpticalFlow.msg
@@ -7,7 +7,7 @@ uint32 device_id               # unique device ID for the sensor that does not c
 
 float32[2] pixel_flow          # (radians) accumulated optical flow in radians where a positive value is produced by a RH rotation about the body axis
 
-float32[3] delta_angle         # (radians) accumulated gyro radians where a positive value is produced by a RH rotation about the body axis. (NAN if unavailable)
+float32[3] delta_angle         # (radians) accumulated gyro radians where a positive value is produced by a RH rotation of the sensor about the body axis. (NAN if unavailable)
 
 float32 distance_m             # (meters) Distance to the center of the flow field (NAN if unavailable)