AIM: To study the change of corneal topography and morphologic to analyze the clinical effects after topography supported customized ablation(TOSCA)for high myopia with thin corneal thickness.

METHODS: Totally 60 patients(120 eyes)with high myopia received corneal refractive surgery. Preoperative spherical equivalent of patients was from -6.00D to -9.00D, and the mean was -7.20±1.18D, the mean corneal thickness was 511±17.93μm. Then the uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), residual corneal thickness, diopter, corneal topography, simulated keratoscope reading(SIMK), corneal irregularity measurement(CIM), and shapa factor(SF)were examined preoperatively and 1 month, 3 and 6 months postoperatively.

RESULTS: The percentage of UCVA exceeding and being equal to 1.0 at 1 month, 3, 6 months after TOSCA was 96%, 97%, 98%. The diopter after TOSCA was improved evidently and turned to be stable at 6 months. The percentage of corneal topographic pattem after 1 month, 3 and 6 months including smooth pattem was 86%,93%,96% respectively while was relatively stable, and other pattem was seldom. No central islet was fond. Other rectomy shape became regulating gradually. At 1 month, 3 and 6 months post-operation, Simk equivalent value and Simk difference value decreased significantly, and the value of corneal irregularity measurement(CIM)increased too. While the value of corneal shape factor changed to negative direction. These above mentioned parameters showed statistically significant difference compared with those of pre-operation(P<0.05).

CONCLUSION: Examination and analysis on the cornmeal topography before and after TOSCA can clearly display the morphological change of the corneal surface topography and morphology, which helps carry out TOSCA individually and achieve perfect correction.