Abstract
Purpose :
Age-related macula degeneration (AMD) is the most common cause of blindness in people over 65 years in the wetern world. These people are permanently dependent on special visual aids in order to be able to perform visual tasks with reduced restrictions like magnifying glasses or screen readers. In the case of cataract formation special intraocular lenses dependent on the stage of disease might also help.
Methods :
Three different intraocular lenses for patients with AMD were simulated in the Liou-Brennan eye model with a ray-tracing computational software based on literature and patent file data. First, a sulcus based add-on lens with a central add power for magnification in close range. Second, a fresnel prismatic capsular bag intraocular lens, which shifts the central scotome to peripheral regions and third, a double lens system with a sulcus based lens with high positive dioptric power and a capsular bag lens with high negative dioptric power and slight decentrations to deflect light from the center.
Results :
Magnification and beam deflections of the simulated lenses confirm the effect described by the manufacturers. To evaluate the effect for different stages of AMD snellen hooks wer projected on fictious retinal defects of different sizes and cpmpared to coresponding visual acuities. The sulcus based add-on lens is suitable for patients with small defects, whereas the two light deflecting lenses can provide a low level of visual acuity even for larger retinal defects. They are mainly limited by maximum angle of deflection and peripheral receptor density.
Conclusions :
Dependent on the size of the retinal defect, the simulated lenses offer a possibility to maintain a functional visual acuity in patients with AMD. If the size of retinal disturbance is known the most suitable solution for the patient can be choosen.
This is a 2021 ARVO Annual Meeting abstract.