Comparison of the local effects of different intracameral cefuroxime solutions on rabbit cornea

INTRODUCTION: Cataract surgery in our country and around the world is widespread. Improvement of the living conditions and increase elder population leads to an increase in this surgery. Endophthalmitis is a sad statement for both doctor and the patient, is a complication that seen in this type of intraocular surgery. For the prevention of endophthalmitis, several measures are taken before and after surgery. At the end of surgery intraocular various antibiotic injection is one of these measures. Cefuroxime is one of these antibiotics. PURPOSE: We aim to compare the injections of intracameral cefuroxime with and without dilution within the context of its local effects on cornea. METHOD: A total of 28 New Zealand white rabbit eyes were randomized to three groups: group A was injected intracamerally with 1 mg of cefuroxime diluted with 0.1 ml of normal saline (n=7), group B was injected with 1 mg of intracameral cefuroxime diluted with 0.1 ml of balanced salt solution (BSS), and group C received no treatment (control group; n=14). Corneal thickness was measured with pachymetry before and 1 week after the injection. Corneal samples were observed under light, specular and electron microscopes after the rabbits were sacrificed. RESULTS: While mean endothelial cell count was lower in SF group compared to BSS group (p=0.04), there was no difference between BSS group and the control group (p=0.1) There was also a statistically significant difference lower in the normal saline compered to the control group (p=0.02). Although an increase in corneal thickness was found in treatment groups this was not the case for the control group (p=0.03) It was seen on scanning electron microscopy that the corneal endothelial preserved its hexagonal structure. While there was a loss of endothelial microvilli in the treatment groups, it was more prevalent in normal saline sub-group. In contrast, microvilli were preserved in the control group. Dissolution of tight junctions in corneal endothelium was observed in the normal saline group. While there was mitochondrial swelling, coarsening of endoplasmic reticulum, cytoplasmic vacuolization and increase in endothelial cell sizes in treatment groups compared to control, no difference was found between subgroups of treatment.Hematoxylin and eosin staining showed thicker and more edematose corneal stroma in Group A compared to Group B and control group. CONCLUSION: It was found that dilution of intracameral cefuroxime with balanced salt solution was superior to dilution with normal saline regarding toxicity of the endothelial cells and decline in the endothelial cell number causing changes to intracellular and intercellular morphology. Based on these findings, caution should be raised when using normal saline which is not considered isodense to anterior chamber, for the dilution of any medication that will be injected intracamerally. Instead, we recommend using of balanced salt solution or any other solution which have been proven safe in clinical studies for intracameral injections.