Retropupillary iris-claw intraocular lens: A surgical video-based commentary on common pitfalls and training insights

In the evolving landscape of aphakia management without capsular support, retropupillary iris-claw intraocular lens (ICIOL) implantation has gained considerable popularity owing to its relative ease, favorable safety profile, and reproducibility.1,2 Its utility in diverse clinical settings—from trauma to complicated cataract surgery—makes it a valuable tool in the surgical armamentarium of anterior segment and vitreoretinal surgeons alike. Despite its widespread use, structured training programs for ICIOL implantation remain limited. Most surgeons adopt the technique based on anecdotal knowledge, short-term fellowships, or peer-to-peer surgical exposure.3 With newer generations of ophthalmologists entering anterior segment fellowships, there exists a strong need for codified learning resources that emphasize not only the "how" but also the "what to watch out for" during surgery. To bridge this gap, we performed a retrospective review of surgical videos from a tertiary eye care center, analyzing 17 eyes of 17 patients who underwent retropupillary ICIOL implantation by novice surgeons with immense experience in cataract surgeries but less experience in retropupillary iris-claw lens implantation. Six cases were unplanned intraoperative cases, and 11 were second-staged surgeries. Out of the 11 eyes planned as second-staged surgeries, six eyes needed only retropupillary ICIOL implantation for surgical aphakia, whereas five eyes needed vitreo-retinal (VR) surgery in addition. In our series, the uniformly round pupil and intact iris made the iris-claw lens an ideal choice by VR surgeons as well. It shortens operative time especially in combined procedures and avoids suture-related issues like erosion or late breakage as in SFIOL. In all cases, whether unplanned (primary sitting) or planned (secondary sitting) implantation of retropupillary ICIOL, the indication was surgical aphakia with insufficient capsular support and the choice of this procedure was made in cases with good iris anatomy. The primary surgery was done in the same sitting as the cataract surgery. The indications noted for VR surgery in the five cases combined with retropupillary ICIOL were retinal detachment (1), full thickness macular hole (1), Late in the bag subluxated IOL (2), and Nucleus drop (1). The time interval between the first surgery (cataract)/trauma and secondary staged surgery (VR surgery + retropupillary ICIOL) varied between 1 day and 6 months. Our analysis focused on identifying critical surgical steps where errors, delays, or complications most commonly occurred. The results of the video analysis of the retropupillary ICIOL were based on five parameters, and the analysis is outlined in Table 1.Table 1: Analysis of the five critical parametersVisual acuity outcomes at 1 month follow-up varied among the 17 cases: Six patients had visual acuity better than 20/30, ten patients between 20/40 and 20/100, and two patients between 20/200 and 20/320. The reduction in vision in the latter group was attributed to factors such as corneal scarring, diabetic macular edema, cystoid macular edema, advanced glaucoma, and complications following vitrectomy for retinal detachment and macular hole. All patients showed improvement in vision in comparison to the preoperative visual acuity. Although IOL tilt Fig. 1d contributed to some degree of visual decline, other parameters like incorrect side port placement, PI, enclavation attempts, type of enclavation instrument used, and pupil shape at the end of surgery did not affect the visual acuity.Figure 1: (a). Postoperative 1 month image of case of primary iris-claw IOL insertion, showing haptic exposure (circle) and inferior iris defect. Preoperatively, the patient had adherent leucoma with brown cataract. The tented iris was separated from the corneal adhesions for easier delivery of the nucleus. Note the inferior corneal scar and thick arcus senilis obscured the view of the surgery intraoperatively. (b). Postoperative 1 month image of secondary implantation of iris-claw IOL, post intracapsular cataract extraction done 1 month back, showing horizontally peaked pupil due to tissue enclavation within the collarette. (c). Postoperative 1 month image of a patient who underwent vitreo-retinal surgery of posteriorly dislocated IOL bag complex and iris-claw IOL placement. The patient had undergone Descemet stripping endothelial keratoplasty and Ahmed Glaucoma Valve (AGV) surgery in the past. Note the AGV tube (horizontal arrow) pushing the ICIOL optic causing it to tilt anteriorly. The iris shows prominent depigmentation and atrophic changes. (d). Retropupillary ICIOL tilt demonstrated by Pentacam (Oculus, Wetzlar, Germany) image, shown by a vertical arrowElevated IOP was observed in three cases, all of which had not undergone a PI. Postoperatively, all three patients had pupillary block; two were managed medically, while one required Nd-YAG laser iridotomy. Cystoid macular edema occurred in two cases, both of which involved secondary IOL implantation. Management included a posterior subtenon injection of triamcinolone acetonide, which effectively addressed the edema. Discussion The review of surgical videos, particularly for procedures like retropupillary ICIOL implantation, provides invaluable insights for both novice and experienced surgeons. The ideal outcome in retropupillary ICIOL implantation is to have a circular pupil with centered IOL with intact iris defect, no inflammation, and good visual acuity. Achieving this is possible with correct judgements and minimal manipulation of the intraocular structures during the surgery. A video provides a comprehensive, step-by-step demonstration, aiding learners in understanding the sequence and intricacies of each step. The ability to pause, rewind, and rewatch critical segments enables focused analysis of challenging steps, reinforces learning, and minimizes the potential for overlooked details. Consequently, this method not only alleviates preoperative anxiety but also enhances preparedness for future procedures.4 Our observations revealed several key points as follows: 1. Precise marking of incisions for side ports is crucial for the success of the procedure. Side ports are recommended to be like stab incisions with shorter intracorneal tunnels and as posterior as possible for ease of enclavation.5 2. The enclavation rod was identified as the preferred instrument during the procedure. 3. Poor visibility, often due to thick arcus or corneal scarring, poses significant challenges during the enclavation step. 4. Subluxation of the IOL, often due to inadequate assessment of the haptic capture, should be evaluated by gently tugging the iris in the opposite side and ensuring stability before the removal of the IOL holding forceps. 5. Complete removal of viscoelastic from behind the IOL is essential, particularly in cases where a PI has not been performed, to avert postoperative complications like raised IOP. Raised IOP due to early post op inflammation and incomplete viscoelastic removal has been noted in few other studies, similar to our study.6 Different instruments can be employed to secure the haptics, including a 26 G cannula, iris repositor, enclavation rod, and sinskey hook. The choice of instrument is largely influenced by the surgeon's training and instrument availability. Sumitha et al.7 described a surgical technique using a sinskey hook to tuck in the IOL haptics, while Sędziak-Marcinek et al.8 used an enclavation needle for the same purpose. Frisina et al. described a novel technique for needle-guided retro pupillary ICIOL fixation, that minimizes trauma to the delicate iris fibers by precisely capturing an optimal amount of iris tissue within the haptics on both sides at a specific angle.9 However, based on the current study, we recommend the enclavation rod as the most reliable instrument for achieving consistent enclavation. Pupil morphology also warrants careful consideration. In our series, 10 out of 17 cases had circular pupils, while 7 exhibited peaked pupils. Peaked pupils were predominantly associated with medial enclavation and, in some instances, with variations in iris stroma thickness in cases of unclear iris anatomy. Enclavation is recommended to be done beyond the collarette (the thickest region of the iris separating the pupillary and the ciliary zone of iris). Notably, although medial enclavation correlated with the appearance of peaked pupils, it did not adversely affect visual acuity in our study. Madhivanan et al.10 reported an increased incidence of postoperative intraocular pressure spikes and pupil ovalization with iris-claw IOL compared to scleral fixated IOL (SFIOL), although the 1-year postoperative visual outcomes were similar between the two groups. Pupil ovalization is attributed to the entrapment of excessive iris tissue within the haptics. To prevent this complication, it is essential to apply appropriate pressure with both the enclavation instrument and the haptic beneath the iris while tilting the optic, ensuring optimal tissue engagement.5 In this context, the enclavation rod provides the necessary tactile feedback and is therefore recommended. Calzetti et al.11 employed anterior segment optical coherence tomography (AS-OCT) to evaluate the tilt and decentration of iris-claw lenses over time. IOL tilt is that it occurs due to variable amount of iris tissue trapped in each haptic slit.12 This error can be minimized by judging the depth of the dimple on the anterior iris surface. Yulia and Soeharto13 identified IOL decentration as the most common complication in pediatric ectopia lentis cases treated with iris-claw IOLs, attributed it to low scleral rigidity. Our study found that decentration was more pronounced when the haptics were secured at noncorresponding positions on the iris and when the pinching by the haptics was asymmetrical. These observations underscore the importance of achieving symmetrical haptic fixation to minimize decentration and optimize the stability of iris-claw lenses. A comprehensive preoperative assessment of the cornea is crucial, particularly in the area designated for iris clipping. Special attention should be paid to any corneal scars, especially those related to pterygium or arcus senilis located in the peripheral regions. Additionally, a detailed iris evaluation should include an examination for atrophic patches, vascularization, the collarette position, previous PI, colobomas, peripheral anterior synechiae, and adherent leucoma involving the iris. The time required for retropupillary ICIOL implantation, which involves tucking the iris tissue into the haptics, is theoretically less than that for scleral or glued IOL implantation, a finding that has been corroborated by various studies.14 Assessing surgical competency is fundamental to ensuring high standards of patient care and optimal surgical outcomes. Numerous grading systems have been developed to objectively evaluate surgical performance, broadly categorized into intraoperative assessment tools and postoperative outcome measures.15 Our study emphasizes the use of video-based grading systems to enhance surgical outcomes in complex procedures that demand precision. Looking to the future, Kawka et al.16 have discussed the role of artificial intelligence in advancing surgical practice, particularly through robotic surgery and machine learning-based video analytics. These technological innovations are poised to refine surgical training and reduce errors; however, their accuracy will depend on the availability of extensive operative datasets. Our video analysis identified five critical steps that significantly influence surgical outcomes. Focused modifications and targeted training on these manoeuvers may enhance procedural success. Video-based analysis emerges as a valuable tool for mastering complex surgical techniques and preparing surgeons to manage complications effectively. Integrating this approach promises to improve the skills of novice surgeons, standardize the quality of care, and advance the management of aphakia with retro-pupillary ICIOLs, ensuring that future surgeons are well equipped to handle complex cases and adopt innovative techniques.