<prompt> Ocular basement membrane is stained byAlcaine blueGiemsa stainMethylene bluePeriodic acid-Schiff  <response>: Not only ocular almost all basement membranes are stained with PAS Periodic acid-Schiff Because it has mucopolysaccharides Periodic acid-Schiff reactive PAS method is principally used to demonstrate structures rich in polysaccharides glycogen, mucopolysaccharides e.g., ground substance of connective tissues, basement membrane, and mucus, glycoproteins thyroglobulin, and glycolipids. 