Ophthalmology: Corneal hydrops is acute swelling due to a break in Descemet’s membrane, an uncommon complication of keratoconus. Researchers found that by injecting an expansile gas Perfluoropropane (used in retinal surgery) into the anterior chamber (with an iridectomy to prevent angle closure), this corneal edema resolved much faster (by about 1.5 months).  Seems like a lot of surgery for a marginal improvement.