Indications and outcomes of intraocular Lens Exchange among pseudophakic eyes in a Tertiary Referral Center

The results of the present study demonstrate that the main indications for IOL exchange were IOL displacement (subluxation or decentration) followed by corneal decompensation in seven years at a tertiary eye center. Over the last decades, indications for IOL exchange have changed. Refractive surprise, corneal decompensation, and IOL opacification were more common in the early 20s, while IOL dislocation became more prevalent later. The main studies reporting the clinical outcome of IOL exchange are summarized in Table 5 [13,14,15,16,17,18,19].

Table 5 Review of the studies reporting the clinical outcome of IOL exchange

IOL displacement remains a main indication for IOL exchange. IOL displacement of PCIOL is divided into two main categories “in the bag” when the capsule lens complex is displaced and out of the bag, when occurs due to sulcus placement of the IOL. IOL displacement risk is estimated at 0.1% at ten years and 1.7% at 25 years [20]. Various factors including intraoperative complications, ocular factors like PEX, RP, long axial length, and history of previous vitreoretinal surgery or trauma cause IOL displacement. In patients with PEX, progressive separation of the zonules or higher risk of intraoperative complications like posterior capsular rupture (PCR). in a study by Jones et al.,. [6] 40% of PEX patients with IOL dislocation had a PCR intraoperatively. Capsular shrinkage and zonular dehiscence are the proposed mechanisms in retinitis pigmentosa [21].

Corneal decompensation was the second most common indication for IOL exchange in the whole cohort of our patients and the leading cause in patients with AC IOL. This result is in line with studies reporting the indications of IOL exchange in patients with AC IOL. Duran et al. [22] evaluated the indications for and outcomes of 29 cases undergoing anterior chamber IOL explantation and reported that corneal decompensation was the indication for IOL explantation in 22 cases. Three underwent keratoplasty and scleral-fixated IOL implantation; no surgical intervention was performed in the remaining cases. In our center, corneal decompensation was detected by specular microscopy and clinical examination. Concomitant DSAEK was performed in patients with clinical edema while IOL explantation was performed when the endothelial cell counts showed a critical decrease.

Despite the absence in our series, one emerging indication of IOL exchange is patients’ dissatisfaction after multifocal IOL implantation [23, 24] We believe that the future trend in our center will also change toward a higher proportion of patients with multifocal IOL exchange as we can see after 2019 in our center.

IOL explantation can be performed from the anterior or pars plana approach. All patients were explanted through the anterior approach in our series because the patients needing concomitant VR surgery were excluded from this study. In a review by De Rajos et al. [25] the surgical approach for IOL explantation was anterior in 104 cases (73.75%) and posterior in 37 (26.24%). Vitrectomy was performed concurrently with IOL removal in 135 cases, from a limbal approach in 98 cases, and pars plana vitrectomy in 37 cases. The two groups were comparable in terms of visual outcome and postoperative complications.

The time interval between the first surgery and IOL explantation was 4.12 ± 5.6 years in our series, which is comparable with most studies. De Rajos et al. [25] reported the average time from original surgery to IOL explantation was 7.89 ± 5.81 years (range 0.08 to 29); 9.31 ± 7.54 years (range 0.75 to 29) for anterior chamber IOLs, and 7.70 ± 5.55 years (range 0.08 to 28.25) for posterior chamber IOLs (p = 0.529) There was no significant difference between the in-the-bag, the out-of-the-bag IOL dislocation group. In the study by Vounotrypidis et al. [26] the mean period between the primary surgery and the secondary IOL implantation was 8.4 ± 6.5 years (range 0 − 32 years). Goemaere et al. [27] reported that the shortest time interval is in refractive error (29.42 ± 42.46 months), and the most prolonged time is for corneal decompensation (151.83 ± 111.07 months).

There are various surgical options to implant the secondary IOL, including anterior iris-claw IOLs, scleral or iris-fixated IOLs, and retropupillary fixation of iris-claw IOLs. The choice of IOL depends on the availability of IOLs, the status of the posterior capsule and iris, and the surgeon’s experience and preference. In a report by De Rajos et al. [25] retropupillary iris-claw IOL was used in most patients with a favorable outcome. While angle-supported IOLs were implanted in half of the patients in the study by Vounotrypidis and colleagues [26] Iris claw AC-IOL was the most commonly used secondary IOL in our series, followed by scleral-fixated PCIOL. In an ophthalmic technology assessment, reported by the American academy of ophthalmology in 2020, various techniques were compared when there is no capsular support. The OTA team concluded that any single IOL implantation technique in the absence of zonular support showed superiority. Moreover, iris-claw fixated IOL like Artisan was discussed as a good option despite no approval by FDA [28]. Our results add to the literature that iris-claw IOLs can be used with a favorable safety profile after IOL exchange.

Various factors affect the visual outcome after IOL exchange. Postoperative astigmatism due to the lens tilt and incidence of postoperative complications, including IOP rise, RD, or corneal decompensation, limit visual acuity improvement after IOL explantation. The high rate of corneal decompensation could be attributed to the present protocol of our center, in which patients with the clear cornea and abnormal endothelial cell counts did not undergo concomitant keratoplasty.

The retrospective nature of the disease limits our study. Incomplete data in some patients, surgery by different surgeons, and loss of follow-up in some patients leading to attrition bias are among the other limitations of the present study. Patients that left aphakic consist of a high proportion of our patients. These patients were generally patients without capsular support and with early evidence of clinical corneal decompensation and iris claw placement was controversial. Therefore, we decided to leave them aphakic. However, the present study reports a large number of patients from a tertiary referral center with an extended follow-up.

In conclusion, IOLs implantation may require further surgical intervention to prevent more damage to the eye or restoration of visual function. This intervention’s causes are different regarding population characteristics, type of IOL (PC vs. AC), and the study time. In the current research, complications of previous surgery lead to the displacement of the IOL in PC IOL while corneal decompensation in AC IOL was the most common cause for secondary surgical procedures. The main side effects of the second surgery in the current study were glaucoma, CME, RRD, and corneal decompensation.

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