Characteristics of crystalline lens tilt and decentration distribution and related factors in patients with age-related cataract

Objective  To investigate the characteristics of crystalline lens tilt and decentration distribution in age-related cataract patients and analyze the related factors.

Methods  A cross-sectional study was conducted.A total of 585 consecutive patients (1 170 eyes) with bilateral age-related cataracts over the age of 50 were enrolled at Aier Eye Hospital of Wuhan University from January 2022 to March 2022.Bilateral crystalline lens tilt and decentration magnitude and direction were measured by swept-source anterior segment optical coherence tomography.Corneal curvature, white-to-white corneal diameter, anterior chamber depth, lens thickness and axial length were measured using a swept-source optical coherence tomography biometer.The correlation of tilt magnitude and decentration magnitude of crystalline lens was assessed by Pearson linear correlation analysis.The correlation of tilt direction and decentration direction of crystalline lens was assessed by Spearman rank correlation analysis.The influence of age and ocular biometric parameters on crystalline lens tilt and decentration was analyzed by multiple linear regression analysis.This study adhered to the Declaration of Helsinki and was approved by the Ethics Committee of Aier Eye Hospital of Wuhan University (No.2022IRBKY0617).All patients signed the informed consent form before any medical examination.

Results  The mean tilt magnitude was (4.69±1.59)°, of which 6.7% had a tillt ≥7°, and the direction was mainly toward the inferotemporal side with a mirror symmetry between both eyes.The mean decentration magnitude was (0.19±0.11)mm, of which 5.3% had a decentration ≥0.4 mm, and the direction was mainly towards the temporal side.The crystalline lens tilt magnitude was positively correlated with decentration magnitude ( r=0.422, P<0.001) and the crystalline lens tilt direction was positively correlated with decentration direction ( r _s =0.432, P<0.001).There was no significant difference in crystalline lens tilt magnitude between both eyes ( t=0.487, P=0.626), and the crystalline lens decentration was significantly greater in the right eye than in the left eye, with statistically significant difference ( t=2.563, P=0.011).There was no significant difference in crystalline lens tilt and decentration between male and female ( t=1.500, 1.566; both P>0.05).The crystalline lens tilt magnitude was significantly greater in 60-69 years, 70-79 years and 80-89 years groups than in 50-59 years group, and the crystalline lens decentration magnitude was significantly greater in the 80-89 years group than in the 60-69 years group (all P<0.05).The crystalline lens tilt magnitude was smaller in the axial length ≥25 mm group than in the <22 mm group and the 22-<25 mm group, and the differences were statistically significant (both P<0.001).There was no significant difference in crystalline lens decentration magnitude among different axial length groups ( F=1.433, P=0.239).The multiple linear regression analysis revealed that the effects of anterior chamber depth ( B=-0.474, t=-2.115, P=0.035), axial length ( B=-0.258, t=-9.324, P<0.001) and crystalline lens decentration ( B=5.646, t=11.234, P<0.001) on crystalline lens tilt were statistically significant.The influence of lens thickness ( B=-0.032, t=-2.402, P=0.017), axial length ( B=0.010, t=4.406, P<0.001) and crystalline lens tilt ( B=0.032, t=11.234, P<0.001) on crystalline lens decentration were statistically significant.

Conclusions  Among age-related cataract patients aged 50 and above, 6.7% have crystalline lens tilt ≥7°, and 5.3% have crystalline lens decentration ≥0.4 mm.The older the age, the greater the crystalline lens tilt and decentration.The shorter the axial length and the shallower the anterior chamber, the greater the tilt of the lens.The greater the tilt magnitude and decentration, the greater the decentration magnitude and decentration.

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