The implantation of an intraocular lens (IOL) within the capsular bag at the same time of cataract extraction represents the standard of care in cataract surgery. Sometimes a primary IOL implant is not possible due to intraoperative complications or pre-existing conditions, therefore a secondary implantation of an IOL in the anterior or posterior chamber is required. Secondary IOL implantation may concern aphakia, be it traumatic, following complicated cataract surgery, or related to congenital anomalies. The procedure is also used for IOL exchange surgery in case of IOL opacification, or in the management of post- phacoemulsification residual refractive error (post-operative ametropia) and implanting piggyback IOLs in the sulcus.

Recent advances in biotechnology and in microinvasive surgical techniques have made available different devices and different placement strategies: secondary implants may be angle-supported anterior chamber IOLs, scleral-fixated posterior chamber IOLs (sutured or not), or iris-fixated IOLs (in the anterior or posterior chamber). In the case of complex post-traumatic reconstructive surgery, different prostheses with an artificial iris and IOL are available, for simultaneous correction of aphakia and aniridia.

In this Special Issue, we invite clinicians to contribute original research articles, including experimental studies and clinical studies, as well as review articles on secondary IOL implantation techniques and strategies. In particular, we welcome articles about newly developed surgical techniques, recent devices, or original approaches, illustrating and discussing anatomical and/or functional evidence, as well as post-operative outcomes and complications.

Potential topics include but are not limited to the following:

• Mid/long-term results of specific types of secondary IOL implantation
• Comparison between different models or different techniques of implantation
• New devices
• Imaging studies evaluating interactions between implants and the surrounding ocular structures
• The use of an implant model in different etiological scenarios
• Surgical complications