Effect of an Intraocular Lens With Enhanced Peripheral Vision on Gait Performance: a Pilot Study

Due to continuous improvements in the technique of cataract surgery as well as the material and the design of the intraocular lenses (IOLs) over the few past decades, the removal of the opacified lens is considered to be relatively safe surgery with good refractive outcomes and a short rehabilitation time. In conjunction with these improvements of the procedure, the patients' expectations concerning their postoperative visual quality and refractive outcomes are increasing.

Different IOLs have been developed to satisfy the patients' demands. Standard monofocal IOL offer good vision in either the far or the near distance, whereas spectacles are still needed for all other distances. On the other hand, multifocal IOLs allow freedom of glasses in all of the three distances (far, intermediate, near), but are, in most cases, associated with a decrease in contrast sensitivity and induction of disturbing photic phenomena (e.g., halo, starbursts, glare).

Enhanced depth of focus (EDOF) IOLs are another lens option and promise good intermediate vision combined with good vision in the far distance, with spectacles only being needed for reading tasks. However, like multifocal IOLs, these lenses may be accompanied by photic phenomena, although to a lesser extent than with multifocal IOL. Recently, the so-called enhanced monofocal IOLs were introduced to the market. These IOLs are comparable to other monofocal IOLs concerning contrast sensitivity and photic phenomena, but besides offering good far visual acuity, they also slightly enhance the depth of focus with some intermediate distance vision.

However, all of these lenses only provide optimal image quality in the very central visual field. Indeed it was shown that in pseudophakic patients the peripheral vision is decreased compared to phakic patients, reducing the peripheral image quality compared to that of the natural crystalline lens. According to computational and physical modelling experiments, this effect may be due to a higher degree of astigmatism and increased higher-order aberrations (HOAs) in the IOL periphery compared to those of the natural lens. This increase in astigmatism was observed in all pseudophakic individuals and did not depend on the power or the type of the implanted IOL. Peripheral vision is thought to have an impact on contrast resolution and sensitivity, detection of small stimuli and the movement of targets in the periphery, exploration and interpretation of a scene, and peripheral visual crowding. All of these tasks are important for the orientation and navigation of patients in their everyday life and misinterpretation of a scene or missing details while walking may lead to an increased risk of falls or accidents. Therefore, an IOL that improves peripheral vision could lead to a better overall functional visual quality and even patients with loss of central vision might benefit from such devices.

Recently, a new non-diffractive inverted meniscus EDOF IOL, the Art40 IOL, which reduces peripheral astigmatism was introduced to the market. This IOL promises to mimic the natural crystalline lens leading to optimized field curvature, improvement in peripheral vision, and enhanced contrast sensitivity of the patients without introducing photic phenomena. Therefore, the aim of this study is to analyse if the peripheral vision after cataract surgery is increased in patients with this new IOL compared to a standard IOL.