Improvement of the detection ability for zonular weakness before cataract surgery by comparing predicted and measured left-right differences in anterior chamber depth.

PURPOSE: To determine whether comparing the predicted left-right difference in anterior chamber depth (p-ΔACD) derived from left-right difference in the lens thickness (ΔLT) and axial length (ΔAL) with the measured ΔACD (m-ΔACD) can improve the detection ability for zonular weakness before cataract surgery. STUDY DESIGN: Retrospective observational study METHODS: Patients with cataract who underwent phacoemulsification and intraocular lens (IOL) implantation at Iwate Medical University Hospital were enrolled. Using surgical videos and records, these eyes were classified either as eyes with normal zonuls (NZ) or weak zonuls (WZ). To clarify the effects of ΔLT and ΔAL on m-ΔACD in the NZ group, multiple linear regression analysis was performed. Using this regression equation, the p-ΔACD was calculated for all cases. ΔACD residual was calculated by subtracting the p-ΔACD from the m-ΔACD. RESULTS: Of the 1286 patients, 56 eyes were classified as having WZ. The ACD and ΔACD in the WZ group were significantly shallower and larger than those in the NZ group, respectively. The absolute ΔACD residuals of the WZ group were significantly larger than those of the NZ group. The absolute ΔACD residuals were greater as the degree of zonular weakness increased. ROC curve analysis revealed that the AUC of absolute ΔACD residual for detection of WZ was 0.743, superior to that of ACD (0.631) and ΔACD (0.623). Moreover, the AUC for the negative ΔACD residual group was 0.830. CONCLUSIONS: These findings suggest that comparing the p-ΔACD with the m-ΔACD may improve the detection ability for zonular weakness.