The associations of lens power with age, axial length and type 2 diabetes mellitus in Chinese adults aged 50 and above

BACKGROUND: To investigate the associations of lens power with age, axial length (AL), and Type 2 diabetes mellitus (DM) in Chinese adults aged 50 and above. METHODS: Random clustering sampling was used to identify adults aged 50 years and above in urban regions of Shanghai. The participants underwent a comprehensive ophthalmic examination including subjective refraction, autorefraction, and IOL-Master. The crystalline lens power was calculated using Bennett’s formula. RESULTS: A total of 4177 adults were included. A linear decrease in lens power was observed both with age and with AL, followed by a stop of lens power loss after the age of 70 or when AL ≥ 25 mm, respectively. Participants with Type 2 DM presented higher lens power (0.43 diopter (D), p < 0.001) and thicker lens thickness (0.06 mm, p < 0.001). In multivariate regression models, there was a positive correlation between lens power and Type 2 DM when age < 75 years (p < 0.001) or AL < 25 mm (p < 0.001) after adjusting for other factors, while no significant association was found in participants aged ≥ 75 years (p = 0.122) or with AL ≥ 25 mm (p = 0.172). CONCLUSIONS: The lens power in adults aged 50 and above exhibited two stages with age and with AL. Type 2 DM caused an increase in lens power, which was not seen in participants aged ≥ 75 years or with AL ≥ 25 mm.