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Peripheral refraction and image quality in a pseudophakic eye model


Purpose : To evaluate peripheral refraction and image quality in a physical model of the pseudophakic eye where the axial position of the intraocular lens (IOL) and the radius of curvature of the retina could be varied. This device is used to compare the performance of a standard Monofocal IOL to a new type of IOL with an inverted meniscus shape designed to improve peripheral image quality.

Methods : The model of the pseudophakic eye had realistic dimensions with a cornea made of PMMA (radius of curvature 7.73mm, conic constant -0.24) an iris at a depth of 3.55mm (3mm pupil) and an IOL holder with variable distance (0.5 to 1.5mm) from the pupil, simulating a postoperative anterior chamber depth ranging from 4.05 to 5.05 mm. The volume of the artificial eye was filled with distilled water. A board level camera (DFM 72BUC02-ML, Imaging Source, Germany) in a water-tight container with a 200μm glass window was introduced to allow direct recording of retinal images. The camera was mounted on a rotating base where the center of rotation was on the optical axis of the system and the radius ranged from 11 to 13 mm to model different retinal radii of curvature. For each field angle (0, 10, 20, 30 and 40 degrees) the retinal image was optimized for spherocylindrical error using trial lenses. Two types of IOLs were evaluated: a standard monofocal (CT Lucia601P, Zeiss, Germany) and a new meniscus shaped one (ArtIOL, Voptica SL, Spain).

Results : The retinal images recorded revealed a deterioration of retinal image quality with field angle. Peripheral defocus ranged from -1.0 D το +7.5 Ddepending on retinal curvature, IOL position and IOL type. Astigmatism was up to -7.5 D for the standard IOL and was reduced to -3.5D for the meniscus IOL. The condition with the increased IOL depth (5.05mm) required the insertion of a higher power IOL by 1D to maintain central focus without adjusting the overall eye’s axial length. The condition of increased chamber depth and increased IOL power resulted to a small (0.5D) decrease in the relative defocus in the periphery. Astigmatism in this condition was higher in the standard IOL ( -9.0 D) and remained unchanged for the meniscus type IOL.

Conclusions : The experimental setup allowed the direct recording of the retinal image at large field angles. The meniscus-type IOL exhibited less peripheral astigmatism in all conditions and it was more robust in terms of the axial depth of the IOL than the standard lens.

This is a 2021 ARVO Annual Meeting abstract.

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