Corneal hazards in use of Simmons shell

A Simmons tamponade shell was used in 10 cases of post‐trabeculectomy overfiltration leading to shallow (iridocorneal touch) or flat anterior chamber. The Simmons shell was an unqualified success in only three cases. Corneal abscess (one case) and corneal abrasion/epithelial loss (four cases) necessitated premature removal of the shell. Three of the patients with corneal abrasions had a formed anterior chamber at the time of shell removal but this shallowed again within 12 hours. Two of these required surgical reformation of the anterior chamber and one reformed spontaneously. Air entrapment causing corneal dessication was probably responsible for the abrasion/epithelial loss. The patient who developed a corneal abscess was grossly malnourished. Use of the Simmons shell needs close monitoring and it should be removed at the first sign of corneal toxicity (abrasionfepithelial loss). Extreme care is necessary in malnourished cases.