Scleral-fixation of the Akreos^® AO60 lens in vitrectomized eyes: a retrospective analysis of outcomes and complications with emphasis on intraocular lens opacification

Introduction

Background

Achieving precise in-the-bag placement of an intraocular lens (IOL) is the goal in every routine cataract surgery (1). When capsular or zonular support is compromised, such as from trauma or prior surgery, other options like sulcus placement, anterior chamber (AC) placement, iris fixation, or scleral fixation are considered (2-4). Selection of the surgical technique is typically influenced by the patient age, anatomy, ocular co-morbidities, and surgeon preference, among other factors (1,2,4). Although no specific approach has been established to be consistently superior compared to another, each technique has a unique complication profile (3,5).

Rationale and knowledge gap

Over the recent decades, scleral-fixation techniques have continuously evolved, and surgeons have expanded the use of IOLs originally engineered for capsular implantation for off-label indications (5,6). Several different types of IOLs have been utilized, many of which are fixated on the sclera using 10-0/9-0 polypropylene or Prolene sutures. With this approach, suture erosion and breakage, as well as IOL dislocation or tilting, are known complications (7). Hence, techniques to stabilize the IOL and reduce the need for IOL exchange or re-fixation have been explored.

The Akreos^® AO60 IOL (Bausch + Lomb) is a hydrophilic, acrylic, foldable IOL that is unique in that each of its four haptics has large eyelets where nonabsorbable monofilament expanded polytetrafluoroethylene sutures can be passed, allowing a stable four-point IOL fixation. While previous authors have reported use of a similar technique (1-3,7-9), a gap in the discussion about complications associated with this approach still exists. This study presents an analysis of complications associated with the lens implantation procedure, placing an emphasis on IOL opacification.

Objective

This study aims to analyze the complications associated with the implantation of the Akreos^® AO60 IOL using Gore-tex^® sutures, with an emphasis on IOL opacification. We present this article in accordance with the STROBE reporting checklist (available at https://aes.amegroups.com/article/view/10.21037/aes-25-23/rc).

Methods

Study design, duration, and population

This was a single-surgeon, retrospective study conducted in Alberta, Canada. Electronic medical records of consecutive adult patients who underwent scleral-fixation of the Akreos^® AO60 lens using Gore-tex^® sutures from January 2017 to December 2022 were reviewed. Previously vitrectomized eyes and eyes that underwent concurrent vitrectomy and IOL implantation were included. Non-vitrectomized eyes and eyes that only underwent limited anterior vitrectomy prior to scleral-fixation of the IOL were excluded. Patients with an existing Akreos^® AO60 implant that required repositioning or refixation were excluded.

Surgical technique

All surgeries were performed by a single vitreoretinal surgeon (A.K.). The cornea was marked at the 180-degree meridian. Temporal and nasal peritomies were created. The infusion cannula was placed inferotemporally, and two other trocars were placed superiorly on each side. Two additional inferior sclerotomies were placed 4 mm from the superior ports as indicated in Figure 1. A standard three-port 23- or 25-gauge pars plana vitrectomy was performed. Additional steps were performed as necessary.

Figure 1 Position of trocars and sclerotomies (right eye, surgeon’s view).

An Akreos^® AO60 IOL targeted for emmetropia was typically implanted, except when myopia or hyperopia was desirable. A 3.5–4.0 mm superior or temporal corneal tunnel was created. The IOL was placed over the ocular surface, and Gore-tex^® CV-6 or CV-8 sutures were threaded into the haptic eyelets on each side of the lens. These sutures were internalized through the corneal wound and externalized through the sclerotomies. The IOL was subsequently internalized through the corneal wound. The transscleral cannulas were removed to facilitate tying down using Gore-tex^® sutures in a 3-1-1 knot. Knots were buried in the sclerotomies and reinforced with vicryl 7-0 sutures if with significant leak. Partial air exchange with or without injection of perfluoropropane (C₃F₈) or sulfur hexafluoride (SF₆) was performed at the end of the procedure on a case-to-case basis, prior infusion line removal. The conjunctiva was closed using vicryl 7-0 and/or tissue glue.

Data collection

The following information was collected from the Calgary Retina Consultants Electronic Medical Records: age, sex, laterality of affected eye, past ophthalmic history, surgical indication, pertinent systemic history, baseline best-reported visual acuity (BRVA), and intraocular pressure (IOP). BRVA was defined as the best documented VA recorded in the chart on the day of the visit, typically measured with correction, with or without the use of a pinhole. VA was consistently recorded using the same method across all visits to maintain uniformity. Pre-existing systemic conditions such as hypertension, diabetes, and connective tissue diseases were noted. Prior ocular diagnoses, including a history of ocular trauma, glaucoma, ocular hypertension, uveitis, diabetic retinopathy, macular pathology, and previous retinal procedures, were also documented.

Important surgical steps were recorded, including vitrectomy, lensectomy, IOL explantation, silicone oil removal, use of triamcinolone for vitreous staining, use of perfluorocarbon liquid, cryotherapy, endoscopic cyclophotocoagulation, endolaser, AC washout, use of iris hooks, synechiolysis, peripheral iridotomy, use of partial or total air fill, use of gas tamponade, use of acetylcholine chloride, and injection of subconjunctival triamcinolone. Intraoperative findings and complications were documented. BRVA and IOP after 1 month, 3 months, 12 months, and on latest follow-up were noted. Postoperative complications were identified, including the timing, management approach, and outcome.

As this was a retrospective, unmatched cohort study, there is an inherent risk of selection bias and confounding. To minimize these risks, all consecutive eligible patients during the study period were included to reduce selection bias. Data were extracted from standardized electronic medical records, and predefined inclusion and exclusion criteria were applied consistently. Outcome assessment was based on objective clinical measures to reduce observer bias. Although no matching was performed, baseline demographic and clinical characteristics were reported.

Statistical analysis

Statistical analysis was performed using Epi Info^TM and Microsoft Excel 365. Descriptive statistics were employed to describe frequencies and percentages of baseline characteristics and complications. Fisher’s exact test was used to investigate the associations between important complications and possible pre-operative and intraoperative risk factors. Odds ratios (ORs) were calculated using univariate logistic regression analysis, and ORs are presented with 95% confidence intervals (CIs) to indicate the precision of the estimates. Prior to analysis, BRVA was converted to logMAR following published methods (10,11). A Wilcoxon signed-rank test was used to compare baseline BRVA with post-operative BRVA at 1 month, 3 months, 12 months, and on latest follow-up. A P value of <0.05 was considered statistically significant in this study. Missing data were excluded from timepoint-based outcome analyses but included in baseline and intraoperative analyses when available. The retrospective, unmatched cohort design limited the feasibility of meaningful sensitivity testing.

Ethical considerations

This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by regional ethics board of Health Research Ethics Board of Alberta (No. HREBA.CHC-19-0002_MOD2) and individual consent for this retrospective analysis was waived.

Results

Baseline characteristics

A total of 89 eyes from 86 patients were included in the study. The mean follow-up duration was 544 days (range, 1–1,830 days). Ninety-one percent of eyes included had a follow-up duration of at least 4 weeks, and 77.5% were followed for at least 3 months. Baseline characteristics of included eyes are displayed in Table 1. Surgical steps performed are shown in Table 2.

Intraoperative findings and complications

Intraoperative issues were encountered in 8 eyes (9.0%). A localized choroidal hemorrhage developed intraoperatively in a 95-year-old female on aspirin and apixaban whose IOL dislocated after a recent fall. Retinal breaks were found in 7 eyes (7.9%), 6 of which were pseudophakic with dislocated IOLs. One eye had retained lens fragments from a recent complicated cataract surgery and another eye had a recent blunt trauma. All retinal breaks were detected and treated with retinopexy prior to IOL implantation.

Postoperative complications

Table 3 displays the list of post-operative complications. More than half of the post-operative complications (54.5%) were documented within 2 weeks post-operation. New-onset complications were less common between 2- and 6-week post-operation (12.1%), while 33.3% of complications were noted beyond 6 weeks post-operation. Of these complications, 70.4% were either observed or managed medically, while 29.6% required procedural intervention. At the end of the follow-up period, 61.2% of complications attributable to the IOL implantation procedure resolved completely, 35.7% remained stable, and only 3.1% demonstrated worsening. The cases that worsened were eyes diagnosed with uncontrolled glaucoma, repeat corneal graft failure, and secondary macular hole. No eyes developed post-surgical endophthalmitis.

IOP changes

Ocular hypotony developed in 10 eyes (11.2%), diagnosed on the first postoperative day. Two were associated with significant hypotony folds and choroidal effusions that warranted intravitreal gas injection, while 1 eye underwent vitreous and AC washout for dense vitreous hemorrhage and hyphema. Hypotony was not found to be statistically associated with vitrectomy gauge (P=0.49), air/gas exchange at the end of the procedure (P=0.46), or recent intraocular surgery (P=0.08). There was no statistical difference in the occurrence of hypotony in eyes that had prior vitrectomy and eyes that had vitrectomy performed on the same sitting as the IOL implantation (P=0.76).

IOP elevation was documented in 8 eyes (9.0%), 6 of which were noted less than 2 weeks post-operation. Medical management yielded adequate control in 6 eyes, while 2 eyes warranted surgery.

Ocular surface and anterior segment complications

Conjunctival cysts and granulomas were uncommon and developed only in 2 eyes beyond 6 weeks post-operation, with one needing surgical removal. Exposed sutures were documented in 5 eyes (5.6%), 3 of which were surgically revised. Corneal edema was documented in 11 eyes (12.4%), with the majority occurring immediately post-operation. Hyphema occurred in 4.5% and was not found to be statistically associated with the use of anti-platelets or anticoagulants (P=0.71). Prolonged AC inflammation was observed in 3 eyes of 2 patients who both had a prior history of uveitis. No eyes developed uveitis-glaucoma-hyphema (UGH) syndrome.

Posterior segment complications

Vitreous hemorrhage was the most common posterior segment complication (13.5%) and was typically diagnosed on the first post-operative day. It was not statistically associated with the use of anti-platelets or anticoagulants (P=0.50), or recent surgery (P=0.18). Ten of 12 eyes were observed, while 2 that also presented with hypotony, choroidal folds, and vitreous hemorrhage underwent a washout procedure.

Cystoid macular edema (CME) was found in 8 eyes (9.0%), most of which were documented beyond 6 weeks post-operation. Complete resolution was observed in 6 of 8 eyes, while 2 eyes had mild persistent CME. Mild de novo epiretinal membrane formation was observed in 4 eyes, with none warranting surgical intervention. Postoperative macular holes were identified in two eyes: one was pre-existing and persistent, while the other developed de novo following surgery. The newly developed macular hole was successfully repaired, whereas the patient with the persistent macular hole declined further intervention.

Rhegmatogenous retinal detachment developed in 3 eyes (3.4%) 40–99 days after IOL implantation. Two eyes with macula-off detachments had a final VA of counting fingers and hand motions, while 1 eye with macula-splitting retinal detachment retained a vision of 20/40. One eye with exudative retinal detachment associated with choroidal detachment and hypotony received intravitreal gas.

Choroidal detachment developed in 7 eyes (7.9%), noted on the first post-operative day. The detachment was localized in 1 eye and resolved spontaneously without intervention. In the 6 eyes with larger choroidal detachments, 2 presented with elevated IOP, 3 had hypotony, 1 had exudative retinal detachment, and 3 had hyphema. Four eyes were managed with intravitreal gas injection in the clinic, whereas 2 underwent AC and vitreous washout in the operating room. No statistical correlation was found between the occurrence of choroidal detachment and hypertension (P=0.57), use of anti-platelets or anticoagulants (P=0.54), prior trauma (P=0.40), recent intraocular surgery (within 4 weeks; P=0.62), prior vitrectomy (P=0.39), vitrectomy gauge (P=0.54), or use of gas tamponade (P=0.38). The sample size was insufficient to determine whether age was statistically associated with choroidal detachment.

IOL opacification

IOL opacification was documented in 10 eyes (11.2%) of 9 patients. Nine of 10 were documented more than 6 weeks post-operation. The majority were observed; IOL exchange was considered in 3 eyes, but one patient declined further intervention. Table 4 shows the characteristics of eyes with IOL opacification.

Among patients with follow-up duration of at least 3 months (n=69), eyes with IOL opacification were much more likely to have been exposed to air or gas exchange intra- or post-operatively (OR: 12.24; 95% CI, 1.46–103.0; P=0.006). Pre-existing uveitis was not found to be a risk factor for IOL opacification. Of the 11 patients with a history of uveitis prior to IOL implantation, 9 had at least 3 months of follow-up, and 2 of these developed IOL opacification (P=0.61). However, the odds of prolonged AC inflammation and/ or reactivation of uveitis after surgery were higher among patients whose IOL opacified (OR: 14.5; 95% CI, 1.18–178.83; P=0.05). The study did not find any correlation between IOL opacification and diabetes mellitus (P>0.99), hypertension (P=0.31), and ocular hypertension (P=0.30).

Figure 2 shows the appearance of IOL opacification in one of the patients from this cohort. Microscopic examination of the explanted IOLs revealed innumerable laminar crystalline deposits on the surface, as well as within the optic and haptics, each measuring less than 0.001 cm in diameter. The density of the deposits was greatest on the apex of the lens. The size and the appearance of the deposits resemble those seen in previous reports of surface calcium deposition (12,13). The deposits stained with von Kossa stain, confirming the presence of calcium.

Figure 2 Slit lamp and microscopic photographs of an opacified Akreos^® AO60 lens implant. (A) Slit lamp photograph of an opacified scleral-fixated Akreos^® AO60 lens implant from Case 46; (B) gross microscopic photograph of an explanted intraocular lens from the same eye. The patient underwent SF₆ gas-fluid exchange on the first post-operative day secondary to hyphema, vitreous hemorrhage, and choroidal hemorrhage. Vitreous and anterior chamber washout with gas exchange was performed a week later due to hemolytic glaucoma. SF₆, sulfur hexafluoride.

Other IOL issues

Slight IOL decentration was described 8 eyes (9.0%), most noted within 6 weeks from surgery. None of the lenses warranted repositioning. There were no eyes that developed suture breakage, posterior IOL dislocation, or IOL fracture within the follow-up period.

Visual outcomes

A total of 81 eyes were included in the study, all of which had baseline VA recorded. Follow-up VA data were available for the majority of eyes at 1 month (78 eyes), 3 months (60 eyes), and 12 months (33 eyes). The latest available follow-up, regardless of time point, was documented for all included eyes. Eyes were included in specific timepoint analyses based on data availability.

BRVA improved by at least 0.2 logMAR units (~2 ETDRS lines), in 71.6% of eyes. Table 5 shows the mean logMAR values at each timepoint. The greatest improvement in BRVA was observed at 1 month post-operation, after which the BRVA remained stable. Compared to baseline, there was a statistically significant improvement of the BRVA at 1 month and at the latest follow-up (Wilcoxon signed-rank test, P<0.001). VA remained stable (within ±0.2 logMAR units) in 19.8% of eyes, while 8.6% (7 eyes) experienced worsening. Of the 7 eyes with decreased VA from baseline, only one patient was noted to have IOL opacification, which developed following retinal detachment repair. This patient also had a history of glaucoma.

Among eyes the with decreased VA, preexisting factors included a history of remote ocular trauma (3 eyes), uncontrolled glaucoma (4 eyes), diabetic retinopathy (2 eyes), and macular pathology such as dry age-related macular degeneration, epiretinal membrane, or macular hole (3 eyes). Additional comorbidities included prior retinal detachment (1 eye), recurrent corneal graft failure (1 eye), and severe dry eye with symblepharon formation (1 eye). One eye with pre-existing uncontrolled glaucoma and poor medication adherence progressed to no light perception by the end of the follow-up period.

Discussion

This report presents an extensive analysis of complications following the scleral fixation of the Akreos^® AO60 lens with Gore-tex^® sutures in vitrectomized eyes. The majority of the eyes demonstrated good visual outcomes after the IOL implantation technique, with 91.4% having better or similar BRVA at the end of the follow-up period. However, associated complications, while mostly transient, were significant. Several complications reported in this study occurred at rates comparable to published data. Junquiera reported rates of 15% for CME, 10% for transient vitreous hemorrhage, 10% for epiretinal membrane, 5% for retinal detachment, 15% for corneal edema, 20% for suture exposure, and 10% for ocular hypertension after a similar technique (2). In our study, about 3 in every 10 eyes with a post-operative complication required procedural intervention.

A key finding in this cohort is the IOL opacification rate of 11.2%, which is higher than most published reports. Figure 2 shows an explanted lens from one patient, demonstrating multiple granular white opacities both on the surface and within the optic. Junqueira et al. found a transient IOL opacification rate of 5% in a cohort of 20 eyes (2). This was observed in an eye with a history of recurrent anterior uveitis and AC inflammation, which responded to topical steroids (2). Meanwhile, Leuzinger-Dias studied 37 eyes that underwent Akreos implantation and vitrectomy and found an opacification rate of 2.7% (1). A larger study conducted by Belin et al. involving 262 eyes found an opacification rate of 2% (9), although the proportion of vitrectomized eyes in this cohort was not specified. This same study found an opacification rate of 25% for eyes that underwent concurrent or subsequent Descemet’s stripping automated endothelial keratoplasty (DSAEK) (9), supporting the causative effect of air/gas on the opacification of the Akreos^® AO60 lens.

A probable contributing factor to the high opacification rate reported in this study is the significant proportion of eyes exposed to exposure to intra- or post-operative air/gas. Thirty-six percent were exposed to air/gas for various reasons—during surgery to prevent wound leakage and bleeding, or after surgery to address ocular hypotony and retinal detachment. The authors emphasize the importance of pre-operative planning, proper wound creation and sealing, and avoidance of use of intraocular air/gas whenever possible. Post-operative inflammation control may also be helpful. Notably, despite the significant risk of IOL opacification in this cohort, VA was typically preserved. Of the patients whose IOLs opacified, only three were recommended for IOL exchange, and one of them declined the procedure.

Histopathologic studies performed in previous studies showed that IOL deposits are composed of calcium and phosphate on the surface or within the substance of the IOL (12). It is postulated that metabolic changes in the AC in the presence of the gas bubble increase the risk for IOL opacification (12). Breakdown of the blood-aqueous barrier after an intraocular surgery may also be a contributing factor (8). Previous authors have identified diabetes as a risk factor for IOL opacification (9,13,14); however, a correlation was not found in this current study. There have also been reports of IOL opacification after vitrectomy with silicone oil tamponade (1,8). As only one eye underwent vitrectomy with oil tamponade in this cohort, the population in this study is not sufficient to evaluate the correlation between IOL opacification and silicone oil exposure.

This study is limited by its retrospective design, the absence of a control group, use of BRVA as an outcome measure, and incomplete longitudinal follow-up. Follow-up data were unavailable for a subset of eyes due to loss to follow-up; these eyes were included in baseline and intraoperative analyses when data were available but were excluded from timepoint-based outcome analyses. Given that uncomplicated cases may be less likely to return for follow-up, the incidence of late complications may be overestimated.

As a result of the experience with this series, the authors have explored other approaches for secondary IOL implantation and have generally avoided hydrophilic IOLs for patients who are likely to need intraocular air or gas tamponade. The outcomes observed in this cohort may not be fully generalizable to patients who have not undergone vitrectomy or to populations outside of a retina-based surgical setting. The authors advise surgeons to remain cautious when using devices for off-label indications.

Conclusions

This study highlights the safety and efficacy of scleral fixation of the Akreos^® AO60 IOL with Gore-tex^® sutures in vitrectomized eyes. While the majority of the patients experienced favorable visual outcomes, IOL opacification emerged as a significant complication, occurring in 11.2% of eyes, particularly in those exposed to intra- or post-operative air/gas. Despite the high opacification rate, VA was largely preserved, with only a small percentage of patients requiring IOL exchange. The findings emphasize the importance of careful preoperative planning, minimizing intraocular air/gas use, and managing postoperative inflammation to reduce the risk of IOL opacification. Further studies are needed to better understand the contributing factors and long-term outcomes of this technique.

Acknowledgments

The authors thank Shellina Kherani, April Ingram, Dr. Tyler Henry for research support and assistance in obtaining ethics approval.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://aes.amegroups.com/article/view/10.21037/aes-25-23/rc

Data Sharing Statement: Available at https://aes.amegroups.com/article/view/10.21037/aes-25-23/dss

Peer Review File: Available at https://aes.amegroups.com/article/view/10.21037/aes-25-23/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://aes.amegroups.com/article/view/10.21037/aes-25-23/coif). A.K. received grants from Bayer, Novartis, Roche, Allergan, Ophthotech, Regeneron, Regenexbio, Iveris Bio Inc, Opthea, Alexion, received payment or honoraria from Abbvie, Alcon, Bayer, Bausch + Lomb, Novartis, Allergan, Roche, Apellis and received support for attending meetings from Roche. A.K. participation on Advisory Board of Abbvie, Alcon, Bayer, Bausch + Lomb, Novartis, Allergan, Roche, Apellis. A.K. is the Fellowship Director in Office of Surgical Education, Past President of Canadian Retina Society, Member of PGME Fellowship Committee, Treasurer of Retina Society of Alberta and Director of Canadian Retina Research Network. A.K. also the Shareholder of MD Collaborate. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by regional ethics board of Health Research Ethics Board of Alberta (No. HREBA.CHC-19-0002_MOD2) and individual consent for this retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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