Trans-Scleral Plugs Fixated FIL SSF IOL: A Review of the Literature and Comparison with Other Secondary IOL Implants

Purpose. To revise the current literature on FIL SSF (Carlevale) intraocular lens, previously known as Carlevale lens, and to compare their outcomes with those from other secondary IOL implants. Methods. We performed a peer review of the literature regarding FIL SSF IOLs until April 2021 and analyzed the results only of articles with a minimum of 25 cases and a follow-up of at least 6 months. The searches yielded 36 citations, 11 of which were abstracts of meeting presentations that were not included in the analysis because of their limited data. The authors reviewed 25 abstracts and selected six articles of possible clinical relevance to review in full text. Of these, four were considered to be sufficiently clinically relevant. Particularly, we extrapolated data regarding the pre- and postoperative best corrected visual acuities (BCVA) and the complications related to the procedure. The complication rates were then compared with those from a recently published Ophthalmic Technology Assessment by the American Academy of Ophthalmology (AAO) on secondary IOL implants. Results. Four studies with a total of 333 cases were included for results analysis. The BCVA improved in all cases after surgery, as expected. Cystoid macular edema (CME) and increased intraocular pressure were the most common complications, with an incidence of up to 7.4% and 16.5%, respectively. Other IOL types from the AAO report included anterior chamber IOLs, iris fixation IOLs, sutured iris fixation IOLs, sutured scleral fixation IOLs, and sutureless scleral fixation IOLs. There was no statistically significant difference in the rates of postoperative CME (p = 0.20), and vitreous hemorrhage (p = 0.89) between other secondary implants and the FIL SSF IOL, whereas the rate of retinal detachment was significantly less with FIL SSF IOLs (p = 0.04). Conclusion. The results of our study suggest the implantation of FIL SSF IOLs is an effective and safe surgical strategy in cases where there is a lack of capsular support. In fact, their outcomes seem to be comparable to those obtained with the other available secondary IOL implants. According to published literature, the FIL SSF (Carlevale) IOL provides favorable functional results with a low rate of postoperative complications.