Perceptual Learning Improve Visual Function in Patients With Keratoconus

Inclusion Criteria: 1. Aged 9 years or older; 2. Has been diagnosed as Keratoconus,BAD-D≥2.6; 3. Change of Kmax \< 1.0 D and change of BAD-D \<0.4175 betweem the last two Pentacam result; 4. The best corrected visual acuity of both eyes was between 0.1 and 1.0; 5. Has voluntarily agreed to participate in the study by signing the statement of informed consent. Exclusion Criteria: 1. Has history of acute keratoconus; 2. Has other eye diseases or other diseases/conditions causing vision loss; 3. Has eye surgery history in the past 1year; 4. Is currently using local/systemic medications or other interventions that may affect visual function; 5. Receiving other treatments that may affect the results of this study, such as contact lenses during the study; 6. Has any known neurological diseases; 7. Participating in other studies currently that may affect the results of this study; 8. Study other reasons that the physician considers inappropriate for inclusion in the program.