# Laser Processing of Intraocular Lenses
###### Abstract  
Polymeric Intraocular lenses (IOLs) are vital for restoring vision following cataract surgery and for correcting refractive errors. Despite technological and medical advancements, challenges persist in achieving optimal vision and preventing complications. Surface modifications aim to mitigate the risk of posterior capsule opacification (PCO), while pre-operative measurements aid in selecting suitable IOLs. However, individualized solutions are lacking and there is a clear demand for the development of fully customized IOL surfaces. We employ laser micromachining technology for precise modifications via ablation on PMMA and acrylic IOLs, using femtosecond (fs), nanosecond (ns), and diode continuous wave (CW) lasers, at wavelengths ranging from near-ultraviolet to infrared. Characterization reveals controlled ablation patterning, achieving feature sizes from as small as 400 nm to several micrometers. Regular and confocal micro-Raman spectroscopy revealed alterations of the IOL materials' structural integrity for some patterning cases, thus affecting the optical properties, while these can be minimized by the proper selection of micromachining conditions. The results suggest the feasibility of accurate IOL patterning, which could offer personalized vision correction solutions, based on relevant corneal wavefront data, thus surpassing standard lenses, marking a significant advancement in cataract surgery outcomes. intraocular lens; PMMA; acrylic; laser ablation; femtosecond laser; nanosecond laser; continuous wave laser; diode laser; Raman spectroscopy +
Footnote †: journal: Applied  
0000-0002-4146-0710]D.M.M. Nd:YAG laser capsulotomy, it is associated with complications like IOL damage, macular edema, increased intraocular pressure, and a higher risk of retinal detachment [10; 11]. As an alternative to treatment, extensive research has explored the role of IOL surface modifications in reducing PCO incidence. Surface-modified IOLs aim to prevent Lens Epithelial Cell (LEC) migration to the center of the posterior capsule and enhance biocompatibility [12]. While pre-operative measurement of corneal spherical aberration aids in selecting suitable IOLs [13], even the best available lens may not fully meet each patient's unique needs. To address this, the focus is on developing IOLs that integrate comprehensive corneal wavefront data, enabling the creation of fully customized IOL surfaces tailored to individual patient requirements, thus offering personalized vision correction solutions beyond standard lenses. IOLs are typically manufactured by industrial injection molding machines based on specific designs for curvature, thickness, and other optical characteristics. The mass production is efficient; however, there is a clear and strong demand for the on-site rapid customization of IOLs based on relevant corneal wave front data acquired by ophthalmologists at the eye-surgery clinic. Such an approach for IOLs rapid customization is feasible by laser patterning, where further to the low-cost implementation for efficient usage at eye-surgery clinics, a few requirements need to be satisfied such as capability of accurate patterning in the range of a submicron to a few micrometers, minimum optical roughness, and no degradation of IOLs in terms of optical, structural, and compositional characteristics. However, the tolerances in the degradation of optical characteristics have not been fully quantified yet by the ophthalmic surgery community. Although the laser patterning of IOLs is under study by a limited number of research groups during almost the past 20 years, an adequate number of systematic and extended studies with conclusive results on IOL patterning has not yet been achieved. One reason could be that scattered studies internationally are based on available laser sources in various research labs without the capability of a direct comparison, or optimal laser selection, in the same study.