diff --git a/src/glyphset.mjs b/src/glyphset.mjs
index 3e5dab58..4aaa6871 100644
--- a/src/glyphset.mjs
+++ b/src/glyphset.mjs
@@ -62,11 +62,11 @@ if(typeof Symbol !== 'undefined' && Symbol.iterator) {
 
 /**
  * @param  {number} index
- * @return {opentype.Glyph}
+ * @return {opentype.Glyph | undefined}
  */
 GlyphSet.prototype.get = function(index) {
     // this.glyphs[index] is 'undefined' when low memory mode is on. glyph is pushed on request only.
-    if (this.glyphs[index] === undefined) {
+    if (this.font._push && this.glyphs[index] === undefined) {
         this.font._push(index);
         if (typeof this.glyphs[index] === 'function') {
             this.glyphs[index] = this.glyphs[index]();