diff --git a/types/koa-response-time/index.d.ts b/types/koa-response-time/index.d.ts
index d8315353fa..dee77d9267 100644
--- a/types/koa-response-time/index.d.ts
+++ b/types/koa-response-time/index.d.ts
@@ -1,11 +1,27 @@
-// Type definitions for koa-response-time 2.0
+// Type definitions for koa-response-time 2.1
 // Project: https://github.com/koajs/response-time#readme
 // Definitions by: Thor Sedeke <https://github.com/thorsedeke>
 //                 Steven McDowall <https://github.com/sjmcdowall>
+//                 Dwscdv3 <https://github.com/Dwscdv3>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
 import { Middleware } from 'koa';
 
-declare function koa_response_time(): Middleware;
+interface KoaResponseTimeOptions {
+    hrtime?: boolean;
+}
+
+/**
+ * Add X-Response-Time header field.
+ * @param options options dictionary. { hrtime }
+ *
+ *        hrtime: boolean.
+ *          `true` to use time in nanoseconds.
+ *          `false` to use time in milliseconds.
+ *          Default is `false` to keep back compatible.
+ * @api public
+ */
+declare function koa_response_time(options?: KoaResponseTimeOptions): Middleware;
+
 export = koa_response_time;
diff --git a/types/koa-response-time/koa-response-time-tests.ts b/types/koa-response-time/koa-response-time-tests.ts
index 6b35c60f9a..fa4d24639e 100644
--- a/types/koa-response-time/koa-response-time-tests.ts
+++ b/types/koa-response-time/koa-response-time-tests.ts
@@ -1,4 +1,5 @@
 import koaResponseTime = require('koa-response-time');
-import Koa = require('koa');
 
-new Koa().use(koaResponseTime());
+koaResponseTime();
+koaResponseTime({});
+koaResponseTime({ hrtime: true });