Eccrine hidrocystoma, in contrast, are usually small (1–3 mm), located exclusively in the periorbital and lateral canthal area and they are absent at either the upper or lower eyelid margins or in the perimarginal skin, but may be rarely present in the dermis typically at the mid-level of the upper eyelid pretarsal skin, or in the lower eyelid skin near the inferior pole of the lower eyelid tarsus [ 15 ].
Source: wiktionary