Eligibility Criteria:
Inclusion Criteria:
* Age is within the range of 40 - 55 years old.
* After mydriasis, for one eye, the refractive power is within -0.5D - 2.0D and the astigmatism is ≤ 1.0D.
* When measuring uncorrected visual acuity with a standard logarithmic visual acuity chart, the uncorrected distance visual acuity (UDVA) of both eyes is ≥ 1.25, and the uncorrected near visual acuity (UNVA) is ≤ 0.8.
* When using a slit lamp to detect cataract development according to the LOCS Ⅲ grading standard, no NO3 - NC3 or more severe lens opacity is detected; and no ocular surface diseases, visual fatigue, or any corneal diseases (such as dry eye, corneal injury, corneal opacity, keratoconus, or having undergone corneal refractive surgery, etc.) are detected.
* The subject has not used Ginkgo biloba extract dichloride eye drops within 2 weeks; has no known or suspected allergy to digitalis - like drugs; and has not used insulin, anti - anxiety drugs, antidepressants, antipsychotics, antihistamines, antispasmodics, diuretics, etc.
Exclusion Criteria:
* Age is not in the range of 40 - 55 years old.
* After mydriasis, for one eye, the refractive power is higher than 2.0D or lower than -0.5D, or the astigmatism is higher than 1.0D.
* When measuring the uncorrected distance visual acuity (UDVA) of both eyes with a standard logarithmic visual acuity chart, if the UDVA is lower than 1.25, or the uncorrected near visual acuity (UNVA) is higher than 0.8.
* When using a slit lamp to detect cataract development according to the LOCS Ⅲ grading standard, NO3 - NC3 or more severe lens opacity is detected in the lens; or ocular surface diseases, visual fatigue, or any corneal diseases (such as dry eye, corneal injury, corneal opacity, keratoconus, or having undergone corneal refractive surgery, etc.) are detected.
* The subject has used Ginkgo biloba extract dichloride eye drops within 2 weeks; has known or suspected allergy to digitalis - like drugs; or has used insulin, anti - anxiety drugs, antidepressants, antipsychotics, antihistamines, antispasmodics, diuretics, etc.