Is bigger better? Glistenings, forward light scatter and visual performance C. Hull, N. Stanojcic, E. Philippaki, D. O'Brart CityUniversity of London, Centre for Applied Vision Research, London, United Kingdom, ST Thomas’ Hospital, GKT Department of Ophthalmology, London, United Kingdom, Kings College London, Department of Physics, London, United Kingdom, ST Thomas’ Hospital, GKT Department of Ophthalmology, London, United Kingdom

Purpose To evaluate and compare wavefront aberration maps in single-vision (SVL) and progressive power lenses (PPL) of different materials and designs. Methods The monochromatic wavefront aberrations of SVL and PPL were evaluated using a Shack-Hartmann wavefront sensor. The lenses were categorized according to their material, power, design and refractive index. Measurements were taken along vertical and horizontal axes starting from the lens optical center and moving towards its periphery in 3mm steps. Artificial pupils of 3mm and 6mm diameter were used to simulate photopic / mesopic viewing conditions. For each point the average of three measurements was analysed. Zernike expansion coefficients up to 4th order, defocus sphere, astigmatism and paraxial curvature matching were calculated using custom-made scripts in Matlab computational software. Results In all cases the magnitude of aberrations was higher when a 6mm viewing pupil was used. The most prominent aberrations were the second order astigmatic components, especially in PPLs and positive SVLs. Spherical aberration and third order aberrations (coma and trefoil) were more pronounced in specific designs. Finally, the magnitude and the pattern of aberrations are affected by lens material, power and refractive index. Conclusion Wavefront aberration data offers, in addition to the common power mapping, the evaluation of the higher order aberrations profiles of the lens, which may compromise visual performance. This allows a more accurate assessment of the visual enhancement provided by modern PPLs with advanced designs.

An intraocular lens (IOL) is implanted in the eye after a cataract surgery. When an IOL is in an aqueous environment, glistenings that are fluid-filled microvacuoles are often observed. Previously, studies of glistenings involved tedious work of manual glistenings labeling and rough estimation of glistening distribution. This paper proposes a software that can be used for automatic glistenings detection. The software evaluates glistenings appearance in a lens, separating the IOL lens into 3 zones and accurately computingthe average area, density and distribution to assist the user. The results are compared with clinicians hand-drawn ground truth for validation. The proposed GUI front-end is easy to use and very suitable for users who want accurate and quick glistenings detection. Numerical results can be achieved without manual drawing and rough estimation.