Evaluation of the White-to-White Distance in 39,986 Chinese Cataractous Eyes

Abstract

PURPOSE.To investigate the distribution of white-to-white (WTW) distance and its associations with other biometric parameters in Chinese cataractous eyes. METHODS.Data on 39,986 eyes from 23,627 Chinese cataract patients were analyzed. Ocular biometric parameters, including WTW distance, corneal curvature, anterior chamber depth (ACD), lens thickness (LT), central corneal thickness (CCT), and axial length (AL), were obtained using the ZEISS IOLMaster 700. RESULTS.The mean age of patients was 63.7 ± 12.4 years, and 57.61% were female. The mean WTW distance was 11.69 ± 0.46 mm. The WTW distance was larger in male patients than in female patients for all age groups (all P < 0.001). The WTW distance was positively correlated with corneal curvature and ACD and negatively correlated with age, LT, and CCT (all P < 0.001). Multivariable analysis revealed that a larger WTW distance was associated with younger age; male gender; larger corneal curvature, ACD, and LT; and thinner CCT (all P < 0.001). Notably, the association between WTW distance and AL was not linear. As the AL increased, the WTW distance initially increased, reached a peak in the group with ALs of 24.5 to 26 mm, and then slowly decreased. However, all of the myopic eyes (AL > 24.5 mm) still had larger WTWs than the normal and short eyes (AL ≤ 24.5 mm). CONCLUSIONS.In Chinese cataractous eyes, the WTW distance was larger in younger male patients with flatter corneas, deeper anterior chambers, thicker lenses, and thinner central corneas. The association between WTW distance and AL was not linear, and WTW distance was the largest in eyes with ALs of 24.5 to 26 mm.

Distribution of White-to-White Corneal Diameter and Anterior Chamber Depth in Chinese Myopic Patients

“…While in Wei et al's study the participants were cataractous patients aged 63.7 ± 12.4 years, our study population was young myopic adults with a mean age of 25.14 ± 5.41 years. Different from our study, the WTW and ACD in Wei et al's study, might be affected by older age and the cataract ( 14 ).…”

“…Precise preoperative WTW and ACD measurement are significantly associated with accurate IOL positioning after cataract surgery, which is one of the important factors related to satisfactory postoperative visual outcomes ( 8 , 9 , 29 ). In a recent study, larger WTW was observed in younger male patients and eyes with flatter corneas, deeper anterior chambers, thicker lenses, and thinner central corneal thickness ( 14 ). The largest WTW was found in eyes with axial length of 24.5 to 26 mm ( 14 ).…”

“…In a recent study, larger WTW was observed in younger male patients and eyes with flatter corneas, deeper anterior chambers, thicker lenses, and thinner central corneal thickness ( 14 ). The largest WTW was found in eyes with axial length of 24.5 to 26 mm ( 14 ). Some of these findings seemed to be different from our results.…”

“…However, results from these reports may not be directly applied to our patients due to possible ethnical differences in the anterior segment anatomy ( 1 ). In a recent study, the distribution of WTW was investigated in Chinese cataractous patients aged 63.7 ± 12.4 years ( 14 ). To date, little information is known about WTW and ACD distribution in young Chinese myopic adults, who represent the largest population of refractive surgery candidates in the world.…”

Distribution and internal correlations of corneal astigmatism in cataract patients

“…This might indicate that a smaller cornea or a longer axis is more likely to exhibit a higher astigmatism. Similar patterns were confirmed by a recent study in 39,986 Chinese cataractous eyes 26 . Further study should be performed to clarify the relationships between corneal astigmatism and other ocular characteristics.…”