This study is a multi-center study, which collects data from multiple regions to obtain the general biological characteristics of the Chinese population. The formula for calculating the artificial lens power based on foreign populations is effectively modified based on the Chinese population.

①Relevant domestic studies on the biological characteristics of the eye are mainly limited to a certain city and region. Most of the studies that represent the biological characteristics of the general population in China and the differences in biological parameters at home and abroad are in the research process, or Semi-finished products.

②The investigators found in clinical observation that the eyeball biological data of the Chinese population may not be consistent with the foreign population.

③ This study is the first study of human eye biological parameters based on different regions of large-scale populations in China, which is of great significance for understanding the human eye structure in different regions of China.

Inclusion Criteria:

• patients aged over 50 years

Exclusion Criteria:

• history of refractive surgery,
• corneal diseases
• ocular inflammation
• trauma

Select elderly cataract patients from different regions of China (at least one representative city in each of east, south, west, north, and central China) who were treated in Aier Eye Hospital.