Abstract
Purpose: :
To simulate and evaluate the changes in retinal images of pseudophakic eyes with astigmatism by toric intraocular lens (IOL) correction under various conditions.
Methods: :
Retinal images of a Landolt ring (0.4 LogMAR) in pseudophakic eyes with astigmatism were simulated under various conditions following correction by a toric IOL employing our original computer software which can simulate the retinal images including the effect of higher-order aberrations. The retinal images in pseudophakic eyes with -1.0 D and -1.5 D of astigmatism were simulated at 5, 4, 2, 1, and 0.5 m, and compared with simulations without a toric IOL correction. The pupil diameter was set at 3 mm in all simulations. Each simulated retinal image was analyzed using a computer software (Adobe Photoshop elements 4.0) and the contrast of the gap of the Landolt ring was calculated. The depth of field was evaluated in each condition. The simulations of retinal images in pseudophakic eyes with astigmatism and a toric IOL correction for 5 m were also evaluated under conditions assuming 4 different rotational misalignment by 0, 10, 20, and 30 degrees, and three additional conditions of decentration by 0, 0.2, 0.4 mm.
Results: :
The quality of the simulated retinal image was greatly improved by toric IOL correction, and the depth of field was also greater in the eyes with toric IOL correction. The retinal image contrast was greater in eyes with a toric IOL correction than in eyes without an astigmatic correction, even when the rotational misalignment was 20 degrees. The decentration of a toric IOL did not greatly influence the retinal image quality.
Conclusions: :
Visual simulation revealed that astigmatic correction with a toric IOL improved retinal image quality despite the increase in higher-order aberrations due to misalignment.
Keywords: intraocular lens • aberrations • refractive surgery: optical quality