diff --git a/src/main/java/qupath/lib/images/servers/omero/OmeroShapes.java b/src/main/java/qupath/lib/images/servers/omero/OmeroShapes.java
index 99aeb82..4cd48e5 100644
--- a/src/main/java/qupath/lib/images/servers/omero/OmeroShapes.java
+++ b/src/main/java/qupath/lib/images/servers/omero/OmeroShapes.java
@@ -217,11 +217,11 @@ private static int ARGBToRGBA(int argb) {
 	public static abstract class OmeroShape {
 		
 		@SerializedName(value = "TheC")
-		private int c = -1;
+		private Integer c;
 		@SerializedName(value = "TheZ")
-		private int z;
+		private Integer z;
 		@SerializedName(value = "TheT")
-		private int t;
+		private Integer t;
 		
 		@SerializedName(value = "@type")
 		private String type;
@@ -471,4 +471,4 @@ private static String pointsToString(List<Point2> points) {
 		
 	}
 	
-}
\ No newline at end of file
+}