diff --git a/explainer.md b/explainer.md
index c136b57..f26eee5 100644
--- a/explainer.md
+++ b/explainer.md
@@ -236,7 +236,7 @@ interface XRCPUDepthInformation : XRDepthInformation {
   // Data format is determined by session's depthDataFormat attribute.
   [SameObject] readonly attribute ArrayBuffer data;
 
-  float getDepthInMeters(unsigned long column, unsigned long row);
+  float getDepthInMeters(float x, float y);
 };
 
 interface XRWebGLDepthInformation : XRDepthInformation {