Comparison of Three Intraocular Lens Implantation Procedures for Aphakic Eyes With Insufficient Capsular Support: A Network Meta-analysis

New Device for the Correction of Aphakia Without Capsular Support

PURPOSE

This study describes a prototype developed for aphakia without capsular support (AWCS) and its proof of concept.

METHODS

This descriptive study used a 3D software to create and analyze virtual prototypes before manufacturing. A nylon-6/nylon-6.6 copolymer filament and a 3D printer were used for prototyping. A device implantation technique was developed using a 23-gauge hypodermic needle. Two opposing markings, 2 mm posterior to the limbus, were made to determine the location of the scleral punctures and the final position of the device. After adequate centralization and positioning of the device, its haptics were cut and cauterized to generate thermal modeling of the extremity and allow the thickening of the tips (flange), serving as an anchoring mechanism to the sclera. The efficacy and adequacy of the technique and device were then evaluated.

RESULTS

Vitreous tissue extrusion was not observed during the sclerotomy. The device was well fixed to the sclera; however, adequate IOL stability and centralization still needed to be achieved. The surgeon evaluated the adequacy of all the other devices' characteristics.

CONCLUSIONS

The development of a technology prototype for correcting AWCS was possible. Although the proposed prototype met most of the established concept guidelines, the stability of the IOL position remains challenging.

Application of modified Yamane technique in intrascleral intraocular lens fixation combined with or without iris reconstruction

AIMS

To explore the application and long-term clinical effects of modified Yamane technique in intrascleral intraocular lens (IOL) fixation combined with or without iris reconstruction.

SETTINGS AND DESIGN

The data of patients receiving IOL fixation with modified Yamane technique in an ophthalmology department between December 2021 and August 2023 were analyzed retrospectively. The longest follow-up duration was > 12 months.

METHODS AND MATERIAL

The trailing haptic was fixed with the needle before the leading haptic. The silicone haptic stoppers were used to stabilize the IOL when iris reconstruction was combined. Preoperative and postoperative best-corrected visual acuity (BCVA), corneal endothelial cells (CECs), postoperative intraocular pressure (IOP), surgical indications and methods, and postoperative complications were recorded. Anterior segment optical coherence tomography (OCT) was used to evaluate IOL decentration and tilt. The paired sample t-test or Wilcoxon rank sum test were used to compare the results of the same index before and after the operation.

RESULTS

Twelve patients (12 eyes) were included in this cohort. There were 1 case of IOL dislocation, eight cases of lens dislocation or subluxation, and three cases of aphakia. Traumatic lens dislocation was the main cause of aphakia. Primary lens extraction was performed in previous surgeries, and all three were combined with pars plana vitrectomy (PPV). Four of 12 patients underwent IOL fixation and iris reconstruction. The mean age of participants was 63 ± 10.61 years. The mean BCVA increased from 0.89 ± 0.72 logMAR to 0.39 ± 0.56 logMAR at the last visit (p < 0.05). The postoperative relative refractive error was - 0.13 ± 0.42 D (-0.60 D to + 0.57 D). The OCT showed that the IOLs were well centered, with a mean decentration of 0.20 ± 0.13 mm and a mean tilt of 2.31°±0.93°. Ten patients did not experience any complications.

CONCLUSIONS

The modified Yamane technique in IOL fixation surgery, especially combined with iris reconstruction, reduces operation difficulty, increases operational stability and safety, and improves postoperative visual acuity without serious intra- or postoperative complications. The long-term improvement effect was remarkable.

Long-term outcomes of iris-sutured subluxated intraocular lenses

PURPOSE

This study evaluated the long-term outcomes of managing posterior chamber intra-ocular lens (IOL) (PCIOL) subluxation through pars plana vitrectomy (PPV) with IOL iris suturing.

SETTINGS AND DESIGN

Retrospective chart review.

METHODS

Patients who underwent PPV with iris-sutured IOL (IS-IOL) for IOL subluxation between January 2008 and April 2021 at a tertiary center with a minimum of 6 months of follow-up were included. The patients were divided into two groups: those who had prior PPV and those who had not undergone the procedure.

RESULTS

A total of 54 patients underwent iris suturing of a subluxated IOL. Among them, 36 (66%) had previously undergone PPV, while 18 patients (33%) had not. The etiology of PCIOL subluxation was uncertain in 20 (37.0%), prior PPV in 17 (32%), and following complicated cataract surgery in 11 (20%) cases. The mean time between original IOL insertion and IS-IOL was 6.1 ± 7.0 years. The mean follow-up duration was 46.8 ± 39.7 months. The mean post-operative best corrected visual acuity (BCVA) was logMAR 0.43 ± 0.52 at final follow-up, a significant improvement from pre-operative BCVA. Vision was significantly better in the group with no prior PPV (logMAR 0.54 ± 0.59 vs. 0.21 ± 0.23 at final follow-up, P = 0.026). At final follow-up, 34 (63%) eyes had BCVA of 20/40 or better. The most common complication was cystoid macular edema, attributed to the IS-IOL in 13 (21.4%) eyes, 11 (68.6%) of which resolved or improved.

CONCLUSIONS

The management of posterior chamber IOL subluxations with PPV and iris suturing of the subluxated IOL is a safe technique that provides excellent long-term visual outcomes.

A meta-analysis of sutureless scleral-fixated intraocular lens versus retropupillary iris claw intraocular lens for the management of aphakia

This study compared the visual outcomes and complications between sutureless scleral-fixated intraocular lens and iris claw intraocular lens implantation in aphakia without adequate capsule and/or zonule support. Studies comparing the clinical outcomes of scleral-fixated intraocular lens and iris claw intraocular lens implantation published until April 2022 were retrieved from the PubMed, EMBASE, Cochrane Library, and Google Scholar databases. The outcomes included postoperative final visual acuity, surgical time, surgery-induced astigmatism, and complications. The weighted mean difference and odds ratio were calculated. Two randomized controlled trials and five cohort studies, including 244 and 290 eyes in the scleral-fixated intraocular lens group and iris claw group, respectively, were included. Scleral-fixated intraocular lens implantation results in a better postoperative final corrected distance visual acuity compared with iris claw intraocular lens implantation; however, it is more time-consuming. Scleral-fixated intraocular lens implantation seems to have lesser incidences of surgery-induced astigmatism. Furthermore, both procedures have a similar complication rate. Therefore, based on current best evidence, these two procedures should be considered according to patient's conditions.

Aetiology and Management of IOL Dislocations

Early (< 3 months) intraocular lens (IOL) dislocation occurs due to insufficient fixation in the capsular bag, while late dislocation (≥ 3 months) is due to increasing insufficiency of the zonular apparatus. Iris-fixated IOL (IFIOL) and suture- or sutureless-fixated scleral IOL (SFIOL) are currently the most commonly used methods when IOL exchange is indicated. Different methods of scleral fixation with or without sutures have been described. The most important techniques are summarised in this paper. IFIOL and SFIOL allow comparable visual outcomes but differ in their risk profile. The decision of which method to use should be made case by case and in accordance with the surgeon's preference.

Improving Effective Lens Position Prediction for Transscleral Fixation of Intraocular Lens Among Congenital Ectopia Lentis Patients

PURPOSE

To introduce a method of predicting effective lens position (ELP) among congenital ectopia lentis (CEL) patients undergoing transscleral fixation of intraocular lens (IOL), and evaluate its effect on improving refractive outcome by utilizing the Sanders-Retzlaff-Kraff / theoretical (SRK/T) formula.

DESIGN

Retrospective cross-sectional study.

METHODS

A training set (93 eyes) and validation set (25 eyes) was included. Z value as the distance between the iris plane and a hypothetic postoperative IOL position was introduced in this study. The Z-modified ELP consisted of corneal height (Ch) and Z (ELP = Ch + Z), and Ch was calculated by keratometry (Km) and white-to-white (WTW). The value of Z was identified by linear regression formula with the involvement of axial length (AL), Km, WTW, age, and gender. The comparison of mean (MAE) and mediate absolute error (MedAE) among Z-modified SRK/T formula, SRK/T, Holladay I, and Hoffer Q formula was performed to evaluate the performance of Z-modified SRK/T formula.

RESULTS

Z value was associated with AL, K, WTW, and age (Z = offset + 15.1093 × lg (AL) + 0.0953899 × Km - 0.3910268 × WTW + 0.0164197 × Age - 19.34804). The Z-modified ELP has good accuracy with no difference to back-calculated ELP. The accuracy of Z-modified SRK/T formula was better than other formulas (P < .001) as the MAE was 0.24 ± 0.19 diopter (D) and MedAE was 0.22 D (95% CI: 0.01-0.57 D). Sixty-four percent of eyes had a refractive error smaller than ±0.25 D, and none of the subjects had a prediction error greater than ±0.75 D.

CONCLUSIONS

ELP of CEL can be accurately predicted by AL, Km, WTW, and age. Z-modified SRK/T formula improved on the current formula by improving predicting accuracy of ELP and may serve as a promising formula for CEL patients with transscleral fixation of IOL.

Face and Content Validity of an Artificial Eye Model for Secondary Intraocular Lens Fixation via Yamane Technique

Purpose

To assess the face and content validity of an artificial eye model for secondary intraocular lens (IOL) fixation via the Yamane technique.

Methods

Ophthalmologists and residents participated in a 90-minute simulation session on secondary IOL fixation via the Yamane technique. Hands-on practice of this technique was performed on an artificial eye, the Bioniko Okulo BR8. After, all ophthalmologists answered an 18-question survey assessing the face and content validity of the model. Survey responses were recorded on a 5-point double-headed Likert scale, ranging from strongly agree (1)-to-strongly disagree (5) (Figure 1).

Results

Twenty-three surveys were completed. Respondents rated the survey with a median response of 1 (strongly agree)-to-3 (neutral). Highest ratings for the model were received for "usefulness for training residents", and "easier to set up and clean-up compared to a cadaver". Lowest ratings were received for realism of the model compared to cadaveric eyes. Statistical analysis revealed no significant difference among identified groups. Ratings for face and content validity were viewed favorably, both with an overall median response of 2.00 (agree).

Conclusion

The Bioniko Okulo BR8 shows promise as a valid tool for practicing secondary IOL fixation via the Yamane technique. Considering recent guidelines in competency-based ophthalmology education programs, this model may be a valuable tool over traditional techniques for teaching and improving surgical skill amongst trainees.

Relationship between Postoperative Anterior Chamber Depth and Refraction Based on the Haptic Fix Position in Intraocular Lens Intrascleral Fixation

The aim of this study was to analyze the refraction and iris capture tendency regarding the fixation position with respect to the intrascleral fixation (ISF) of intraocular lenses. Consecutive patients who underwent ISF 1.5 mm (ISF 1.5, 45 eyes) and 2.0 mm (ISF 2.0, 55 eyes) from the corneal limbus with NX60, as well as those who underwent normal phacoemulsification with in-the-bag ZCB00V (ZCB, 50 eyes), were enrolled. The anterior chamber depth (post-op ACD), the estimated ACD when using the SRK/T (post-op ACD-predicted ACD), and the refractive error (post-op MRSE, and the predicted MRSE) were all calculated. In addition, the postoperative iris capture was also investigated. The post-op MRSE-predicted MRSE values were: -0.59, 0.02, and 0.00 D (ISF 1.5, ISF 2.0, and ZCB) (p < 0.05, between ISF 1.5 vs. ISF 2.0 and ZCB); the post-op ACD values were: 4.00, 4.17, and 4.29 mm (p < 0.05, ISF 1.5 vs. ZCB); and the post-op ACD-predicted ACD values were: -2.03, -1.98, and -1.60 mm (p < 0.05, between ZCB vs. ISF 1.5 and ISF 2.0). The iris capture occurred in four eyes with regard to ISF 1.5 and three eyes with ISF 2.0 (p = 0.52). Moreover, ISF 2.0 possessed 0.6D hyperopia and 0.17 mm deeper anterior chamber depth. The refractive error of ISF 2.0 was less than that of ISF 1.5. Lastly, no significant iris capture onset was noted between ISF 1.5 mm and 2.0 mm.

Long-term outcomes of modified glued versus flanged intrascleral haptic fixation techniques for secondary intraocular lenses

PURPOSE

To report the long-term refractive outcomes and complications of two scleral fixation techniques for secondary intraocular lenses (IOL).

METHODS

Consecutive patients who underwent secondary IOL insertion at a tertiary care academic hospital using either modified glued ("glued") or flanged intrascleral haptic fixation (FISHF) techniques with over 12 months of follow-up were retrospectively reviewed. Pre- and postoperative corrected distance visual acuity (CDVA), postoperative complications, and refractive surprises were reported.

RESULTS

Thirty-eight patients underwent "glued" fixation and 22 underwent FISHF, with mean follow-up times of 3.1 ± 0.5 and 2.0 ± 1.2 years, respectively. Aphakia secondary to trauma was the main surgical indication. MA50BM or MA60AC IOLs (Alcon Laboratories Inc., Fort Worth, TX) were implanted in 92% of "glued" patients, while CT Lucia 602 IOLs (Carl Zeiss Meditec Inc., Dublin, CA) were used in 96% of FISHF patients. Postoperative spherical equivalent significantly improved compared to preoperative values (p < 0.001). No significant difference in CDVA was seen between the two techniques. FISHF resulted in mean hyperopic surprises of + 0.81D and + 0.69D using the Holladay 2 and Barrett Universal II formulae, respectively, which was significantly greater than the "glued" patients. A higher rate of IOL dislocation was seen in the "glued" cohort (13%) compared to FISHF (0%).

CONCLUSIONS

Retrospective long-term outcomes of patients with complex ocular comorbidities undergoing a modified "glued" technique demonstrated a higher rate of IOL dislocation but more predictable refractive outcomes compared to the FISHF technique. The FISHF technique resulted in a significant hyperopic shift using fourth-generation IOL calculators.

Accuracy of intraocular lens power calculation formulas for eyes with scleral-sutured intraocular lens in congenital ectopia lentis

Purpose

To compare the accuracy of intraocular lens calculation formulas in eyes with congenital ectopia lentis (CEL) that underwent scleral-fixated intraocular lens (IOL) implantation.

Setting

Zhongshan Ophthalmic Center, Guangzhou, China.

Design

Retrospective, consecutive case-series study.

Methods

A total of 158 eyes from 158 patients diagnosed from December 12, 2017 to November 16, 2020 with congenital ectopia lentis and undergoing a lensectomy and a Rayner 920H or 970C model IOL scleral-fixation were retrospectively reviewed. The prediction errors (PEs) of the spherical equivalent of eight formulas, Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO), Haigis, Hoffer Q, Holladay 1, Kane, Hill-Radial Basis Function 3.0 (RBF 3.0) and SRK/T were compared.

Results

For CEL patients with sclera-sutured IOL, all eight formulas yielded myopic PEs without constants optimization. After such optimization, the performance of each formula ranked by median absolute error (MedAE) from lowest to highest in diopter, was SRK/T (0.47), EVO (0.48), Kane (0.52), BUII (0.53), Hoffer Q (0.58), Holladay 1 (0.59), Haigis (0.61), and RBF 3.0 (0.62). The EVO and SRK/T formulas had the highest prediction accuracy concerning the percentage of cases within the +/- 0.50 D range of PE and within +/- 1.00 D range of PE in eyes experienced sclera-sutured IOL surgery, respectively.

Conclusion

All formulas with unoptimized constants produced myopic PEs. After optimization, the SRK/T and EVO formula were the two recommended formulas due to having the lowest MedAE and the highest percentage of PE in the range of +/- 0.50 D for CEL patients with sclera-sutured IOL implantations.

Scleral-fixated intraocular lens implants-evolution of surgical techniques and future developments

Varied options are available for the implantation of secondary intraocular lens implants in the absence of zonular or capsular support. Loss of the capsule can occur in the context of complicated cataract surgery, trauma or inherited conditions such as Marfan syndrome or pseudoexfoliation. Approaches to overcome this include optical measures such as the use of spectacles or contact lenses, and surgical therapy incorporating the use of anterior chamber, iris-fixated or scleral-fixated lenses. Surgical techniques to implant scleral-fixated lenses have undergone various modifications, since the first publication of sutured intrascleral fixation described in the 1980s. However, despite the advances in surgical techniques, studies are limited either by their retrospective nature, small sample size and most importantly small duration of follow-up. This comprehensive review aims to amalgamate the evolution of various surgical techniques with regards to intrascleral lens fixation and suggests areas for future development.

Outcomes and complications of iris-fixated intraocular lenses in cases with inadequate capsular support and complex ophthalmic history

BACKGROUND

To report the indications, visual outcomes, and intra-operative and post-operative complications of iris-sutured posterior chamber intraocular lens (IOL) in eyes with inadequate capsular support and complex ocular history.

METHODS

A chart review and data analysis of eyes that underwent iris fixation of posterior chamber (PC) IOL for correction of aphakia, dislocated and subluxed IOLs, ectopia lentis, and IOL exchange. Data included clinical risk factors, associated eye conditions, previous surgeries, and concomitant procedures. The pre-operative and post-operative vision, manifest refraction, endothelial cell density, intraocular pressure (IOP), as well as intra-operative and post-operative complications were also recorded.

RESULTS

One hundred and seventeen eyes from 114 patients were examined with a mean follow-up of 22.4 months. The most common identifiable predisposing risk factor was high myopia in 23 eyes. A significant improvement in uncorrected and best corrected visual acuity compared with baseline was observed. The most common post-operative complications included recurrent IOL subluxation in 16 (13.7%) eyes, IOP spike in 7 (5.9%) eyes, cystoid macular oedema in 5 (4.3%) eyes, and epiretinal membrane formation in 4 (3.4%) eyes. There was one (0.85%) case of sterile endophthalmitis.

CONCLUSIONS

Iris suture fixation of PC IOLs is a good treatment option for eyes with inadequate capsular support and complex ocular history.