The streaks produced by ordinary glass are mainly caused by uneven batches; corrosion of refractory materials (mainly introduced Al); and agitation during the manufacture of glass products.

Therefore, optical glass must start from these aspects. The raw materials require purity>99%, impurities are less than a few hundred thousandths, and the particle size and weighing of the raw materials have high requirements. All furnaces use ceramic or platinum as refractory materials. The molding generally only uses the pouring method, the rolling method, the cylinder breaking method, and the liquid method, which effectively prevents the agitation of the glass during molding.