To evaluate the corneal biomechanical properties of stable eyes with abnormal morphology, and introduce a biomechanical stable index to evaluate the stability of the eyes with abnormal morphology at the first diagnosis.

Inclusion Criteria:

1. Best corrected visual acuity (BCVA) ≥ 20/20;
2. No other eye diseases except myopia and astigmatism;
3. The cornea was transparent, and there was no cloud or pannus;
4. No clinical manifestation of keratoconus（Corneal stromal thinning, Cone-shaped anterior protrusions, Fleischers ring, Vogts striae, Epithelial or subepithelial scarring） Exclusion Criteria:1) corneal disease;

2) ocular trauma; 3) Patients were required to stop wearing soft contact lenses for at least 2 weeks and rigid contact lenses for at least 4 weeks before examination; 4) Pregnant and lactating women;

Patients premedicated for refractive surgery