Purpose We aimed to compare the local effects of intracameral cefuroxime diluted in normal saline (SF groups) against those of cefuroxime in balanced salt solution (BSS group) on the cornea of rabbits. Materials and methods Fourteen New Zealand albino rabbits were randomised into two groups. The right eyes of the rabbits in the SF group I were injected intracamerally with 1 mg cefuroxime diluted with 0.1 mL normal saline (n = 7), whereas the right eyes of the BSS group II were injected with 1 mg intracameral cefuroxime diluted with 0.1 mL with balance salt solution, and the left eyes of all rabbits received no treatment group III (control group). Corneal thickness was measured with pachymetry before and 1 week after the injection. Corneal samples were evaluated with light, specular and electron microscopy. Results Mean endothelial cell count was lower in the SF than in the BSS and control groups. Although an increase in corneal thickness was found in both treatment groups, this was not the case for the control group. The corneal endothelium preserved its hexagonal structure in all groups. Although both treatment groups showed a loss of endothelial microvilli, this was more prevalent in the SF group. However, microvilli were preserved in the control group. Dissolution of tight junctions in corneal endothelium was observed in the SF group only. Mitochondrial swelling, coarsening of endoplasmic reticulum, cytoplasmic vacuolisation, and increased endothelial cell sizes were the same in both treatment groups but was not observed in the control group. Thicker and more oedematous corneal stroma were observed in the SF group compared with the BSS and control groups. Conclusion Dilution of intracameral cefuroxime in BSS yielded superior results compared with dilution in normal saline owing to toxicity to the endothelial cells and decline in the endothelial cell number, resulting in intracellular and intercellular morphological changes. BSS or any other solution with proven safety should be used in clinical studies.