Abstract
Purpose:
To determine how lens thickness contributes to lens prediction errors in eyes with shallow anterior chamber depths.
Methods:
This retrospective chart review analyzed refractive results from 41 eyes with anterior chamber depths more shallow than 2.7 mm undergoing microcoaxial phacoemulsification with implantation of AcrySof single-piece intraocular lens (SN60WF). Preoperative parameters included axial length, keratometry measurements, anterior chamber depth, lens thickness, and white-to-white diameter obtained from Lenstar (Haag-Streit). These were used to calculate a predicted spherical equivalent using the Holladay 1, Holladay 2, SRK/T, and Hoffer Q formulas. Lens constants were optimized for this group of patients. The post-operative spherical equivalent was predicted for each patient and the error (actual spherical equivalent - predicted spherical equivalent) was determined.
Results:
Linear regression of error with lens thickness revealed a myopic error as lens thickness decreased and a hyperopic error as lens thickness increased. This was consistent across all the formulas including Holladay 2.
Conclusions:
In cataractous eyes with shallow anterior chambers, it appears that lens thickness is important in achieving the target refraction. Our data suggests that the effective lens position is more posterior when the lens is thick leaving the patient with a more hyperopic error than predicted. Conversely, a thin lens seems to be associated with a more anterior effective lens position leaving the patient with a more myopic refractive error.
Keywords: 445 cataract •
567 intraocular lens