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ESCRS Eye Journal Club
In episode 23 of the interactive video programme EyeJC, Artemis Matsou (Greece) and Imran Yusuf (UK) discussed “Phakic intraocular lens explantation: a series of 175 surgeries” with Professors José Güell and Miguel Rechichi.
Phakic intraocular lenses (PIOLs) are a popular lensbased refractive surgical option for the correction of moderate to high (and even low) refractive errors, offering the advantages of preserving corneal integrity and crystalline lens accommodation. The indications for PIOL implantation have expanded in recent years with the evolution of PIOL design and longer follow-up data supporting their safety. Unsurprisingly, PIOLs come with an “expiry date”, and removal becomes necessary as patients age and cataract extraction is indicated.
In their retrospective study “Phakic intraocular lens explantation: a series of 175 surgeries”, Heitor Marques and colleagues investigated the main indications for PIOL explantation over a 10-year period. The study identified 175 eyes that required PIOL removal, with three types of lenses included: two anterior chamber (AC) (iris-fixated [IF], 65.5% and angle-supported [AS], 25.5%) and a posterior chamber (PC, 9.1%). Mean global survival time from implantation to removal was approximately 13 years in this cohort comprised exclusively of explanted PIOLs. Surprisingly, the AS PIOLs had the longest survival at nearly 15 years, an interesting observation considering these lenses were withdrawn from the market due to significant endothelial cell loss (ECL). The main indications for explantation were cataract formation (44%, mainly with PC type) and ECL (50%, mainly with AC types), with 4.6% of eyes requiring a corneal transplant due to corneal decompensation.
The outcomes of this study were discussed with Professors José Güell and Miguel Rechichi during the ESCRS Eye Journal
Club, who offered further insights. AC PIOLs dominated the PIOL market until the introduction of PC PIOLs, explaining why they form the majority of explanted PIOLs in this study, with ECL as primary cause for explantation. With surgeons’ preference favouring newer generation PC PIOLs, future studies will have these data for comparison. Regardless of the common perception that AC PIOLs can lead to ECL and PC PIOLs to cataract, both complications can be encountered with both types of lenses, making long-term (decades!) follow-up crucial—in contrast to laser refractive surgery, where patients can usually be safely discharged to their optician. Of note, cases with corneal decompensation in this study were all lost to follow-up.
The role of chronic microinflammation also merits further investigation as a contributing factor to ECL and early cataract development in these eyes. Although not examined in this study, microinflammation may represent a mechanism that might explain chronic changes to structures not in direct contact with the PIOL. Moreover, ECL seems to arrest after PIOL removal with even reversal of corneal oedema in some cases. The observed increase in EC density is more likely attributable to repopulation and morphological alterations of the endothelial cells. Professor Güell suggested ECL greater than two standard deviations from the physiological loss on two consecutive visits should prompt removal of the lens, particularly when the rate of loss is increasing.
As a take-home message, both speakers highlighted their positive experience with PIOL outcomes and the importance of patient counselling regarding PIOL survival time, possible complications, and requirement for long-term follow-up for early identification of complications, irrespective of PIOL selection.
For more information on the study, see: Marques JH, Baptista PM, Abreu AC, Monteiro S, Pinto MDC. “Phakic intraocular lens explantation: a series of 175 surgeries”, Journal of Cataract & Refractive Surgery. 2022, Apr 4. doi: 10.1097/j.jcrs.0000000000000952.
Cronin B, Ghosh A, Chang C. “Oxygen-supplemented Transepithelial Accelerated Corneal Crosslinking with Pulsed Irradation for Progressive Keratoconus: One-Year Outcomes”, Journal of Cataract & Refractive Surgery. 2022, Apr 4. doi: 10.1097/j.jcrs.0000000000000952.
