diff --git a/src/gui/painting/qpaintengineex.cpp b/src/gui/painting/qpaintengineex.cpp
index 9f07af92e40..f4cbf15fc70 100644
--- a/src/gui/painting/qpaintengineex.cpp
+++ b/src/gui/painting/qpaintengineex.cpp
@@ -1090,9 +1090,14 @@ bool QPaintEngineEx::shouldDrawCachedGlyphs(QFontEngine *fontEngine, const QTran
     if (fontEngine->glyphFormat == QFontEngine::Format_ARGB)
         return true;
 
+    static const int maxCachedGlyphSizeSquared = std::pow([]{
+        if (int env = qEnvironmentVariableIntValue("QT_MAX_CACHED_GLYPH_SIZE"))
+            return env;
+        return QT_MAX_CACHED_GLYPH_SIZE;
+    }(), 2);
+
     qreal pixelSize = fontEngine->fontDef.pixelSize;
-    return (pixelSize * pixelSize * qAbs(m.determinant())) <
-            QT_MAX_CACHED_GLYPH_SIZE * QT_MAX_CACHED_GLYPH_SIZE;
+    return (pixelSize * pixelSize * qAbs(m.determinant())) < maxCachedGlyphSizeSquared;
 }
 
 QT_END_NAMESPACE