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Quality of images with toric intraocular lenses (IOLs)

Session Details

Session Title: Cataract I

Session Date/Time: Friday 14/02/2014 | 10:30-12:30

Paper Time: 11:34

Venue: Kosovel Hall (Level -2)

First Author: : DanieleTognetto ITALY

Co Author(s): :    Manlio Antonuccio   Silvia Rinaldi           

Abstract Details

Purpose:

Objective evaluation of the quality of images obtained with toric intraocular lenses (IOLs) at different axis position

Setting:

University Eye Clinic of Trieste, Italy and Department of Industrial and Information Engineering, University of Trieste, Italy

Methods:

An experimental opto-electronic test bench including an electro-opto-mechanical device simulates the optical and geometric characteristics of the human eye. A cylindrical lens of -3.75 D has been placed in front of the optic bench to simulate corneal astigmatism. Toric IOLs at different axis positions were analized evaluating the quality of different images. In this study we analyzed visual quality of images using the Visual Information Fidelity criterion (VIF). A relevant software was realized to capture, store images and evaluate their quality in accordance with established criteria.

Results:

Images were acquired at different IOL positioning: in the first acquisition the axis of the lens corresponded to the axis of the astigmatism and we considered this image as the base one. Subsequently an IOL rotation of -5°, -10°,-15°,-20°, -25°, -30°,-35°, -40°, -45° has been induced and the obtained images have been captured, stored and analyzed by the software. Image quality comparison and VIF calculation have been performed between the base image and each of the images obtained after IOL axis rotation. When the axis of the lens was rotated within 5° from the proper position, image definition decayed of 7% . At axis rotation 5° to 15° the loss was of about 20%; for values of axis rotation within 15-25° the waste was 40%, while for axis rotation values major than 40°-45° the image definition decayed of more than 50% as for images obtained with no cylindrical correction.

Conclusions:

IOL rotation have an important impact in terms of image quality. The objective evaluation of images obtained at different axis rotational positions demonstrated that for IOL rotations within 5° the image quality did not change significantly, while for values major than 40°-45° the quality of image decayed nullifying the corrective effect of the toric lens FINANCIAL INTEREST: NONE