Movie clip visibility triggered by Mouse position

[Solowalker]

I am trying to toggle the visibility of a movieclip on the condition that mouseY is within a specific position. Code below is my approach

this.addEventListener(MouseEvent.MOUSE_MOVE, showLD2);

function showLD2 (e:MouseEvent):void {
		if (mouseY >= 614){
		LD2nd.visible = true;
		}else 
		{
		LD2nd.visible = false;
		}
}

However, the problem is the movieclip is hidden immediately at the slightest move of the mouse instead of when the mouse is at the specified position. What might be wrong with my approach?