OBJECTIVE: This study aimed to analyse the correlation between corneal astigmatism and disparity in corneal thickness. METHODS: In this retrospective analysis, data from 342 patients (684 eyes) were collected. The Sirius three-dimensional corneal topography system was utilised to ascertain the mean corneal thickness of the meridians. Correlation analyses were conducted between the mean difference in corneal thickness along the two principal meridians and the astigmatic values computed by simulated keratometry values (Sim-K) for total corneal astigmatism (TCA) and posterior corneal astigmatism (PCA), respectively. Variability in differential corneal thickness (DCT) values at different TCA levels was analysed. The variability of DCT within the 3-mm corneal range at different differences between whole-eye astigmatism and TCA (Difference between corneal astigmatism and computer optometry, DWT) levels was analysed. RESULTS: Within the ranges of 3, 4.5, and 6 mm, the mean corneal thickness of the meridian with the maximum refractive power (Sim-K CONCLUSION: The meridian with the maximum refractive power had a thicker mean corneal thickness than the meridian with the minimum refractive power. The difference in corneal thickness is closely related to the severity of corneal astigmatism. The extent of residual astigmatism is influenced by this thickness difference.