Abstract
Purpose:
To determine if the zonular laxity associated with pseudoexfoliation (PXF) syndrome results in deepening of the anterior chamber in the supine position when compared to upright, and whether this affects refractive outcomes after cataract surgery.
Methods:
This was a retrospective chart review of patients who underwent uncomplicated phacoemulsification cataract surgery at Weill Cornell Medical Center from April 2010 to September 2012. Patients with PXF on whom biometry measurements had been obtained by 1) supine immersion ultrasound (A-Scan Synergy, Malvern, PA) and 2) upright A-scan (IOLMaster, Carl Zeiss, Oberkochen, Germany), were selected. Age and sex matched controls without PXF were selected using the same criteria. Post-operative refraction predicted by IOLMaster and 30 day post-operative refraction spherical equivalent data were collected. The Student's t-test was used to compare 1) the change in anterior chamber depth (ACD) from upright to supine in PXF and control patients, and 2) the difference between predicted post-operative refraction and actual post-operative spherical equivalent in PXF and non-PXF patients.
Results:
22 patients with PXF and 22 controls were included. Mean ACD increased from 3.026mm±0.054mm to 3.095mm±0.051mm in eyes with PXF, and decreased from 3.061mm±0.059mm to 3.014mm±0.067mm in control eyes with change in posture from upright to supine. The increase in ACD with postural change in eyes with PXF was statistically significant (p=0.036) while the decrease in ACD in non-PXF eyes was not significant. Eyes with PXF had post-operative refractions that were more hyperopic than predicted (+0.327±0.069 diopters). Control eyes also had post-operative refractions that were more hyperopic than predicted (0.045±0.083 diopters), however, the difference was significantly greater in eyes with PXF (p=0.012). The post-operative hyperopic shift did not significantly correlate with the degree of ACD increase (R=0.37, p=0.118).
Conclusions:
Eyes with PXF show an increase in the ACD in the supine position, which is not seen in non-PXF eyes, and are more likely to have mild post-operative hyperopic shifts. In patients with PXF who exhibit an increase in ACD in the supine position relative to the upright, surgeons may wish to aim for a slightly myopic outcome (-0.25 to -0.50D) to minimize the risk of unintended post-operative hyperopia.
Keywords: 445 cataract •
676 refraction •
413 aging