Biometry of the posterior lens capsule: a new method to predict pseudophakic anterior chamber depth.

The distance between the anterior corneal vertex and the posterior lens capsule was measured in 60 eyes before and three months after extracapsular cataract extraction with implantation of a posterior chamber lens. The preoperative capsule position ranged from 6.15 mm to 8.60 mm and averaged 7.64 +/- 0.47 mm (+/- SD). All posterior lens capsules had moved anteriorly following surgery. The postoperative capsule position ranged from 4.31 mm to 5.53 mm and averaged 4.93 +/- 0.29 mm. The postoperative capsule position could be predicted by the following optimized multiple linear regression equation: 2.4 + 0.011 x patient age + 0.171 x anterior chamber depth + 0.051 x axial length. The multiple correlation coefficient was 0.48. The postoperative anterior depth could be predicted with a correlation coefficient of 0.61 by subtracting both the averaged value of the clinical "laser space" and the exact central implant thickness from the estimated position of the posterior lens capsule. We suggest that this principle for predicting the postoperative anterior chamber depth may be useful for a number of lenses with different designs.