Effect of astigmatism on apparent accommodation in pseudophakic eyes.

PURPOSE: To investigate the factors affecting apparent accommodation in pseudophakic eyes from a clinical viewpoint and the effects of corneal and refractive astigmatism on this accommodation from an optical viewpoint.

METHODS

We retrospectively examined 62 eyes of 33 patients who had undergone phacoemulsification with monofocal intraocular lens implantation. We quantitatively assessed the amplitude of apparent accommodation using an accommodometer 3 months after surgery. Multiple regression analysis was used to assess the factors affecting apparent accommodation. We also estimated the accommodation in eyes with corneal astigmatism by optical simulation.

RESULTS

The mean amplitude of apparent accommodation was 1.58 = 0.65 D. Explanatory variables relevant to this accommodation were in order of influence, pupil diameter (partial regression coefficient B = 0.293, p = 0.008), and corneal multifocality (B = 0.101, p = 0.03). Other explanatory variables such as age, gender, axial length, corneal astigmatism, and refractive astigmatism showed no significant relationship with this accommodation. The estimated apparent accommodations for a 3.0 mm pupil by optical simulation were 1.25, 1.25, 1.25, 0.75, and 0 D, in eyes with corneal astigmatism of 0, 0.5, 1.0, 1.5, and 2.0 D, respectively. Similar results were obtained for a 4.0 mm pupil.

CONCLUSIONS

Eyes with smaller pupil diameter and eyes with greater corneal multifocality are more predisposed to have greater apparent accommodation. However, from clinical and optical viewpoints, corneal or refractive astigmatism does not significantly contribute to apparent accommodation after cataract surgery, suggesting that it may be of less significance that the astigmatism is consciously retained in consideration of this accommodation in astigmatic eyes.