ASCRS News: ASCRS/EyeWorld Journal Club
December 2021

by Andres Parra, MD

Following cataract extraction with IOL implantation, late in-the-bag IOL dislocation is a known phenomenon with an estimated incidence of 0.5–1%.^1,2 This type of IOL dislocation occurs on average 6–12 years after otherwise uneventful cataract surgery, and risk factors include pseudoexfoliation, trauma, high myopia, vitreoretinal surgery, and uveitis.^1–4 The decision to pursue surgery to address this dislocation is based off a myriad of factors including whether the patient experiences visual symptoms subjectively, the degree of dislocation of the IOL, as well as presumed risk of further dislocation.⁵ Surgical approaches can include IOL repositioning by various techniques or IOL exchange. Existing literature raises concerns regarding the suitability of using 1-piece IOLs in repositioning, primarily due to potential for uveitis-glaucoma-hyphema (UGH) syndrome due to iris chafing.^6,7 However, the authors of this study hypothesized that if IOL dislocation occurs in the bag and repositioning surgery techniques maintain the IOL in the bag, there should be a similar safety profile for the 1-piece IOL when compared to the 3-piece IOL design.

Design and methods

This prospective cohort study aimed to evaluate the long-term efficacy and safety following IOL repositioning of varying IOL designs for late in-the-bag dislocations. The IOL designs included 1-piece foldable (n=17), 3-piece foldable (n=28), plate haptic (n=8), and 1-piece rigid (n=1). The surgical technique employed scleral suturing via anterior approach using an ab externo suture loop technique with two scleral fixation points 180 degrees apart and placed approximately 1.8–2.0 mm behind the limbus using two 10-0 polypropylene sutures. All surgeries were performed by one surgeon. 

Extensive preop screening took place to ensure all dislocations were exclusively in the bag and no dislocation was found to be out of the bag. Patients were examined postop as well as at the 6-month, 1-year, and 2-year postop marks by the same ophthalmologists. The primary outcome of safety was determined as the absence of postop UGH syndrome or redislocation, however, the examination also tracked other complications such as iritis, IOP changes, and clinically relevant IOL decentration. The other primary outcome was efficacy in terms of postop corrected distance visual acuity (CDVA) and postop change in spherical equivalent. Postop spherical equivalent was compared to habitual refraction prior to IOL dislocation to determine the change in spherical equivalent.  

Predisposing risk factors in the population included pseudoexfoliation in 42 eyes (78%), myopia in 10 eyes (19%), previous vitreoretinal surgery in 5 eyes (9%), blunt trauma in 4 eyes (7%), and history of uveitis in 3 eyes (6%), with overlap of risk factors in some eyes and no predisposing risk factors in three eyes (6%). 

Summary of results

The main analysis compared repositioning of the two most common IOL designs, the 1-piece and the 3-piece IOL, accounting for uncertainty due to attrition in long-term follow-up using intention-to-treat analysis.

There were no instances of UGH in either of the two groups. The 3-piece IOL group had one case of mild iritis with history of chronic ocular inflammation prior to cataract surgery, one case of redislocation with a broken haptic discovered intraoperatively during repositioning, and one case of corneal decompensation. No serious complications occurred. Clinical decentration was noted in 2 eyes in the 1-piece group and 5 eyes in the 3-piece group, none of which were found to be symptomatic. 

Postop mean CDVA at final observation was similar between the 1-piece IOL at 0.36 logMAR (0.14 to 0.59) and the 3-piece IOL at 0.29 logMAR (0.12 to 0.46) (P=0.58). The mean change in spherical equivalent at final observation was –0.08 D (95% CI, –0.93 to 0.77) in the 1-piece group and –0.98 (–1.73 to –0.23) in the 3-piece IOL group (P=0.11). 

Discussion

Existing literature raises safety concerns regarding a 1-piece IOL for repositioning in cases of late in-the-bag IOL dislocation, primarily due to potential for UGH syndrome. UGH syndrome can be caused by any IOL in the sulcus⁴ and even in the capsular bag with possible causes including a deformed haptic, out-of-the bag dislocation of the IOL or haptic, Soemmering’s ring, or pseudophacodonesis.^8,9 This study suggests a similar safety profile between 1-piece IOL designs and 3-piece IOL designs with no instances of UGH syndrome. In the study, potential causes of UGH are addressed both preop by excluding any out-of-the bag dislocations and intraoperatively by using a surgical technique that secures the IOL with scleral sutures and thus should eliminate pseudophacodonesis. 

It is also noted that while CDVA was similar between the two IOL design groups, the postop change in spherical equivalent was –0.98 D for the 3-piece IOL group compared to –0.08 D for the 1-piece IOL group. This may be due to differences in the biomechanics of the IOLs as well as differences in haptic thickness and angle. This suggests that for repositioning of 3-piece IOLs, more posterior placement of the scleral sutures may be considered to avoid the associated relative myopic shift. 

Some limitations of this study include an analysis that is limited to comparing only the 1-piece and 3-piece foldable IOL designs, primarily because of insufficient power due to a low number of eyes with other IOL designs. While foldable 1-piece and 3-piece designs are the most common designs used during CEIOL, future studies comparing more IOL designs and materials would be beneficial. In addition, all cases were performed by a single surgeon using a singular technique. While this technique was found to be relatively safe in terms of outcomes, it would be beneficial to compare this technique with others, such as Yamane, as well as other scleral suturing techniques with and without scleral flaps. 

Another discussion point brought up during the ASCRS Journal Club was the use of 10-0 polypropylene sutures compared to 9-0 polypropylene or 8-0 Gore-Tex sutures. Given evidence of late dislocations of scleral-sutured PCIOL due to degradation of suture material over time, the use of larger diameter than 10-0 polypropylene suture material as well as placement of haptic and sutures in the ciliary sulcus may promote attachment of scar tissue and enhance long-term stability of scleral-fixated IOLs.¹⁰ 

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Repositioning surgery of different intraocular lens designs in eyes with late in-the-bag intraocular lens dislocation

Marius Dalby, MD, Liv Drolsum, MD, Olav Kristianslund, MD 
J Cataract Refract Surg. 2021;47(9):1147–1152.

• Purpose: To evaluate the long-term efficacy and safety after intraocular lens (IOL) repositioning by scleral suturing of 1-piece IOL compared with other IOL designs in the treatment of late in-the-bag IOL dislocation.
• Setting: Patients referred to Oslo University Hospital.
• Design: Prospective cohort study.
• Methods: The study comprised 54 patients (54 eyes) with late in-the-bag IOL dislocation treated with IOL repositioning by scleral sutures (10-0 polypropylene). All operations were performed with an anterior approach and by one surgeon. The following IOL designs were repositioned: 1-piece foldable (n=17), 3-piece foldable (n=28), plate haptic (n=8), and 1-piece rigid (n=1). Patients were evaluated comprehensively before surgery, and 6 months (80%), 1 year (67%), and 2 years (61%) after surgery. The main outcome measures were efficacy in terms of corrected distance visual acuity (CDVA) and spherical equivalent (SE), and safety in terms of complications.
• Results: Postoperative visual acuity was similar for different IOL designs. Mean SE change to final observation was –0.08 (95% CI, –0.93, 0.77) in the 1-piece group and –0.98 (–1.73, –0.23) in the 3-piece group (P=.11). In terms of safety, no patients had uveitis-glaucoma-hyphema syndrome, retinal detachment, or endophthalmitis. The 3-piece group had 1 case of redislocation and 1 case of iritis. No patients had symptoms related to clinical IOL decentration. Long-term intraocular pressure remained within normal limits with overlapping 95% CIs for different IOLs.
• Conclusions: Repositioning surgery of 1-piece IOLs appears as efficient and safe as that for other IOL designs in the treatment of late in-the-bag IOL dislocation.

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References

1. Monestam E. Frequency of intraocular lens dislocation and pseudophacodonesis, 20 years after cataract surgery—a prospective study. Am J Ophthalmol. 2019;198:215–222.
2. Kristianslund O, et al. Late in-the-bag intraocular lens dislocation: a randomized clinical trial comparing lens repositioning and lens exchange. Ophthalmology. 2017;124:151–159.
3. Dabrowska-Kloda K, et al. Incidence and risk factors of late in-the-bag intraocular lens dislocation: evaluation of 140 eyes between 1992 and 2012. J Cataract Refract Surg. 2015;41:1376–1382.
4. Durr GM, Ahmed IIK. Intraocular lens complications: decentration, uveitis-glaucoma-hyphema syndrome, opacification, and refractive surprises. Ophthalmology. 2020. Online ahead of print.
5. Dalby M, et al. Repositioning surgery of different intraocular lens designs in eyes with late in-the-bag intraocular lens dislocation. J Cataract Refract Surg. 2021;47:1147–1152.
6. Samuelson TW. Managing an unstable subluxated intraocular lens with uncontrolled intraocular pressure and progressing glaucoma: July consultation #1. J Cataract Refract Surg. 2016;42:1098–1099.
7. Ahmed IIK, Snyder ME. Management of dislocated intraocular lenses: Clinicians’ Corner. American Academy of Ophthalmology. 
8. Zhang L, et al. Mechanisms for in-the-bag uveitis-glaucoma-hyphema syndrome. J Cataract Refract Surg. 2014;40:490–492.
9. Boutboul S, et al. Pigmentary glaucoma secondary to in-the-bag intraocular lens implantation. J Cataract Refract Surg. 2008;34:1595–1597.
10. Price MO, et al. Late dislocation of scleral-sutured posterior chamber intraocular lenses. J Cataract Refract Surg. 2005;31:1320–1326.

Contact 

Parra: ASParra@mednet.ucla.edu