Characterizing reflections from intraocular lens implants

Scanning Light Scattering Profiler (SLPS) Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light scattering from intraocular lenses (IOLs) using goniophotometer principles. This protocol describes the SLSP platform and how it employs a 360° rotational photodetector sensor that is scanned around an IOL sample while recording the intensity and location of scattered light as it passes through the IOL medium. The SLSP platform can be used to predict, non-clinically, the propensity for current and novel IOL designs and materials to induce light scatter. Non-clinical evaluation of light scattering properties of IOLs can significantly reduce the number of patient complaints related to unwanted glare, glistening, optical defects, poor image quality, and other phenomena associated with the unintended light scattering. Future studies should be conducted to correlate SLSP data with clinical results to help identify which measured light scatter is most problematic for patients that have undergone cataract surgery subsequent to IOL implantation.

A novel full-angle scanning light scattering profiler to quantitatively evaluate forward and backward light scattering from intraocular lenses

Glare, glistenings, optical defects, dysphotopsia, and poor image quality are a few of the known deficiencies of intraocular lenses (IOLs). All of these optical phenomena are related to light scatter. However, the specific direction that light scatters makes a critical difference between debilitating glare and a slightly noticeable decrease in image quality. Consequently, quantifying the magnitude and direction of scattered light is essential to appropriately evaluate the safety and efficacy of IOLs. In this study, we introduce a full-angle scanning light scattering profiler (SLSP) as a novel approach capable of quantitatively evaluating the light scattering from IOLs with a nearly 360° view. The SLSP method can simulate in situ conditions by controlling the parameters of the light source including angle of incidence. This testing strategy will provide a more effective nonclinical approach for the evaluation of IOL light scatter.

Impact of environmental temperature on optical power properties of intraocular lenses

Optical power properties of lenses and materials in general can be influenced by thermal changes of the material and surrounding medium. In the case of an intraocular lens (IOL) implant, the spherical power (SP), cylinder power, (CP), astigmatism, and spherical aberration are the critical fundamental properties that can significantly impact its efficacy. Directly evaluating how changes in temperature can affect these optical properties may show the importance of considering temperature when evaluating IOL optical characteristics. In this paper, we present a quantitative study on evaluating the impact of environmental temperature changes on IOL fundamental optical properties by testing IOL samples with different materials (e.g., hydrophobic and hydrophilic) and designs (e.g., monofocal and toric) to better encompass types of IOLs in conventional use today. The results from this study demonstrate that significant changes are observed as temperatures are changed from room temperature (20°C) to slightly above body temperature (40°C). Findings indicate that evaluating optical properties at arbitrary temperatures could significantly affect the characterization of IOLs that are already near the tolerance thresholds.