Periorbital fat atrophy - an unfamiliar side effect of prostaglandin analogues.

Prostaglandin F2 alpha (PGF2a) analogues including bimatoprost and travoprost are used worldwide, often as first line topical treatments for glaucoma. We present 2 cases of a newly described side effect of both these topical agents in terms of periorbital fat atrophy. This visually noticeable side effect had features demonstrable on MRI scanning. The periorbital fat atrophy is most apparent with uniocular use and both doctors and patients need to be aware of this side effect before commencing treatment. The effects, however, appear to be reversible with treatment cessation.