Before cataract surgery, subjects in the observation group used iTrace ocular aberration analyzer（itracey Technologies）and IOL-Master 700 biometer to measure the preoperative DLI(Dysfunctional lens index) and SS-OCT image of the lens, and The researchers used the anterior segment slit lamp to take photos of the anterior segment of the subject's lens in a state of dilated pupils .and self-scoring of the preoperative visual quality assessment scale. Healthy subjects in the control group also need to complete the above inspections. After that, three experienced cataract specialist surgeons combined the preoperative optometry data of each subject, the photos of the LOCS III anterior segment and the Catquest-9SF questionnaire score to determine whether each subjects should undergo cataract surgery. The subjects were divided into cataract surgery group and non-surgical group. Finally, statistically study the correlation between the DLI index and the degree of lens opacity that has been collected, and use the ROC curve to calculate the DLI as the best cut-off point of DLI to distinguish whether to perform cataract surgery.

Inclusion Criteria:

• Over 40 years old
• Healthy volunteers with no history of systemic or ocular diseases
• patients with simple age-related cataracts without other ocular diseases
• those who can communicate with the tester at a normal level
• those who can express their own ideas independently

Exclusion Criteria:

• irregular corneal astigmatism
• corneal opacity
• corneal scars
• corneal dystrophy
• shallow of anterior chamber
• retinal abnormalities
• history of eye surgery or laser treatment
• pupil diameter less than 4.00mm in a dark environment
• subjects who did not cooperate well during the examination

Patients with simple age-related cataracts and healthy patients without systemic or eye diseases attending the Eye Optometry Hospital of Wenzhou Medical University