Fig. 3. A magnified picture of the Descemet’s membrane fold (black arrow) trabecular meshwork can occur and have been reported in severe cases.8-10 Therefore, it is important to control the concentration of the solution when antibiotics are added to the irrigating solution in order to prevent postoperative endophthalmitis.1,2,4 However, the exact nontoxic concent- rations of the antibiotics and steroids have not been fully investigated. Montan et al.11 studied doses and exposure durations of cefuroxime when injected in the anterior chamber, reporting that 1 mg/0.1 ml of cefuroxime is safe and maintains a high concentration for one hour postoperatively. Kang et al.12 studied gentamicin toxicity in different concentrations on three types of human corneal cells under culture and suggested that the safe local concentration of gentamicin for endothelial and stromal cell was 1 mg/ml in the human eye. With increasing concentration of gentamicin (from 2 mg/ml BJ Ha, et al. CORNEAL STROMAL INJECTION WITH ANTIBIOTICS to 4 mg/ml), the toxicity of gentamicin to the corneal cells was in direct proportion to its concentration and duration of incubation. The toxicity was the greatest on endothelium; the stroma was affected the least. Petroutsos et al.13 reported that endothelial toxicity occurred when 1 mg/ml of gentamicin was injected into the anterior chamber in rabbit eyes. Medin14 used a weight recording system to demonstrate the possible toxic effect of gentamicin on the endothelium of rabbit corneas stored in organ culture. They reported gentamicin toxicity of from concentrations of 3.0 mg/ml and higher. Lin et al.15 reported that 15% cell damage was found in tissue cultured bovine endothelial cells when exposed to 1.6 mg/ml of gentamicin. Damaged cells recovered their normal morphology after 24 hours. When the concentration of gentamicin was doubled, cell damage reached 40%, and the recovery of cellular morphology was much slower. They concluded that gentamicin should be rationally and carefully used in the intraocular space. Mester and Stein16 studied the effect of gentamicin concentration on rabbit endothelial cells and reported that 0.50% gentamicin was toxic to endothelium, but 0.25% gentamicin was not significantly different as compared to the control. Besides irreversible damage to the corneal endothelium and corneal edema, high concentrations of gentamicin solutions can induce retinal hemorrhage, edema, and obliteration of the retinal vasculature when injected in the vitreous, resulting in optic atrophy, retinal pigment degeneration, or neovascular glaucoma.17,18 In our case, the toxicity of the gentamicin to the corneal endothelium was expected to be significant due to the fact that the concentration of the gentamicin injected in anterior chamber and corneal stroma was 40 times more than that of previously mentioned studies. Wang et al.19 tested the cytotoxicity of five antibiotics (amphotericin-B, colistin-M, sulbenicillin, amikacin, cephra- dine) and a steroid (betamethasone) to cultured porcine corneal endothelial cells and demonstrated that the steroid was less toxic to the endothelium than other antibiotics. In our case, the inadvertent injection of antibiotics and steroids resulted in severe corneal edema from 12 to 4 Fig. 4. Specular microscopy at the site of Figure 2 (arrow, A; arrow head, B) on 16 weeks postoperatively. 243