A stye or hordeolum is a small, painful lump on the inside or outside of the eyelid. It is actually an abscess filled with pus and is usually caused by a staphylococcus bacteria eye infection.Styes are common with most people experiencing one or two of them at some stage in their life.Styes are usually visible on the surface but can appear deeper inside the eyelid. chalazion is very different from a stye and is not an infection. It is instead a firm, round, smooth, painless bump usually some distance from the edge of the lid. A chalazion is a local tissue reaction to oily glandular secretions that were unable to reach the lid surface because the duct was blocked by debris.