Progress of Baggy Eyelid: An Anatomical Study.

Purpose: To examine microscopically the progress of baggy eyelid formation in the lower eyelid.

Methods: Histological evaluation of 17 central lower eyelids (11 right and 6 left) from 13 Japanese cadavers (age range: 36-97 years, average: 73.0 years) was performed. The specimens were fixed in 10% formalin and stained with Masson's Trichrome. The following characteristics were examined: 1) presence of baggy eyelid, 2) thickness of the orbital septum, 3) presence of anterior protrusion of fat and/or orbicularis oculi muscle (OOM), 4) thickness of OOM and subcutaneous tissue at the widest anterior protrusion, and 5) skin thickness.

Results: The findings were divided into 4 stages: stage 0 (2 eyelids in 1 specimen) absent baggy eyelid, all tissues normal, stage 1 (1 eyelid in 1 specimen) absent baggy eyelid, intermediate orbital septum, anterior dome-like protrusion of fat but minimal OOM projection, thick OOM, subcutaneous tissue, and skin, stage 2 (9 eyelids in 7 specimens) absent or minimal baggy eyelid, intermediate orbital septum, anterior dome like protrusion of fat and OOM, intermediate OOM, with thick subcutaneous tissue and skin, stage 3 (5 eyelids in 4 specimens) with present baggy eyelid, thin orbital septum, severe anterior dome like protrusion of fat and OOM, with thin OOM, subcutaneous tissue and thick skin in mild type, with thin skin in severe type.

Conclusions: Baggy eyelid appears to be triggered by the anterior protrusion of fat, followed by thinning of the orbital septum, OOM, and subcutaneous tissue in order. Thinner skin may promote severe entity.