Late in-the-bag intraocular lens dislocation after cataract surgery – a 15 Yearfollow up study at Örebro University Hospital between 2003 and 2018.

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1 Degree project, 30 ECTS June 2019

Late in-the-bag intraocular lens dislocation after cataract surgery – a 15 Year

follow up study at Örebro University Hospital between 2003 and 2018.

Version 2

Author: Diedrik Svanström, MB

School of Medical Sciences Örebro University Örebro Sweden

Supervisor: Sven Crafoord, MD PhD

Department of Ophthalmology Faculty of Medicine and Health

Örebro University Örebro Sweden Word count Abstract: [238] Manuscript: [3365]

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Abstract:

Introduction: Cataract surgery, is nowadays the most common surgical procedure performed

in Sweden. Late in-the-bag intraocular lens dislocation (LITBILD), occurring many years after uneventful surgery, is due to progressive zonular weakness and capsular shrinkage. Known risk factors include among others pseudoexfoliations (PXF), high myopia and previous vitreoretinal surgery. LITBILD has been reported with an increasing frequency in recent years. Thus, there is a value in further investigating this patient group and describe related risk factors.

Aim: Determine the 15-year cumulative risk of LITBILD after standard cataract surgery

2003 in Örebro and describe possible risk factors causing LITBILD.

Method: Retrospective nested case-control study examining patients who underwent cataract

surgery with phacoemulsification in 2003 at Örebro University Hospital. To locate patients within that group who sustained LITBILD ICD10 diagnosis codes relating to LITBILD covering years 2003-2018 were assessed. Each case was matched with two controls of identical sex and age.

Results: The LITBILD group was 9 patients out of 1499 operated with median age at

LITBILD of 80 years (range 57-82). Median time between cataract surgery and LITBILD was 134 months (range 39-167). Glaucoma before and/or after cataract surgery and high intraocular pressure before surgery were independently statistically significant risk factors for LITBILD.

Conclusion: Patients who underwent cataract surgery 2003 had a cumulative risk of 0.6% to

develop LITBILD. 78% of patients with dislocation had one or more of the risk factors studied whilst the control group represented 40% (p=0.08).

Key words: Intraocular lens, cataract surgery, in-the-bag intraocular lens dislocation

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Abbreviations

CTR – capsular tension ring IOL – intraocular lens IOP – intraocular pressure ITB – ‘in the bag’

LITBILD – Late in-the-bag intraocular lens dislocation NCR – Swedish National Cataract Register

OOTB – ‘out of the bag’ PXF – pseudoexfoliation

USÖ – Örebro University Hospital VRS – vitreoretinal surgery

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1 Introduction

Age-related lens opacity, or cataract, is a condition where the ability of the eyes to focus light on the retina gradually decreases primarily due to cumulative age-related changes in the major proteins of the lens [1]. With time these modified proteins aggregate causing the lens to gradually lose its transparency [1]. The condition is normally treated through modern lens surgery, where the opaque lens is removed and an intraocular lens (IOL) is inserted. With its inception during WWII, the first IOLs became a possibility after findings by Harold Ridley, an ophthalmologist operating on British Air Force pilots [2]. He noticed in the eyes of one of his patients, a pilot whose plexiglas canopy had shattered, sending splinters into his eyes, that the material was inert and unlike glass gave no immune response [2]. This gave birth to the idea of using such materials to develop artificial lenses.

Since then, cataract surgery and IOLs have advanced considerably, with implantation of a posterior foldable IOL after using phacoemulsification through a small corneal incision being the preferred technique since the 1990s [3]. In Sweden since 2002, this method has been used in over 99% of cases [4]. In routine cataract surgery, preservation of the lens capsule is anticipated, and the IOL can be placed in the ideal location, that is ‘in the bag’ (ITB) [5], which in turn is connected to the zonula. As discussed by Prajna et al. [6] “the treatment is often a one-time surgical intervention with excellent visual rehabilitation” as well as high rates in patient satisfaction [7]. In complicated surgery, with capsule rupture the IOL can be placed in the ciliary sulcus, ‘out of the bag’ (OOTB) [8]. In rare cases, if there is not sufficient capsular support, an “angle‐supported IOL, an iris‐claw IOL or an IOL fixed to the scleral wall may be used” according to Augustin et al. [9]. As stated by Jakobsson [10], “Serious complications either during surgery as well as in the postoperative period are exceptional” and due to the development of surgical devices and IOLs, cataract surgery is safer than it was 25 years ago [11].

At present, the global annual number of cataract operations amount to the millions [12] and in Sweden alone the frequency has almost tripled in the past twenty years to around 125,000 operations in 2017 [4] making it the most common surgical procedure performed. As discussed by Jakobsson [10] although complication rates are low, at just a few percent

“considering the vast amount of people operated, a considerable number of patients will be affected by adverse effects […] either during the surgical procedure or in the close

postoperative period or even several years after surgery.” As highlighted by Krepste [11] “IOL dislocation is one of the most serious complications to cataract surgery” and although rare, it is a well known occurrence [13]. As many as 20% of cataract surgeons had faced this

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6 problem according to a poll in 2001 taken at the American Academy of Ophthalmology during a course on complications [14,15]. Initially dislocation of the IOL occurred OOTB, primarily in the early postoperative period due to poor IOL fixation and complicated cataract surgery [16,17]. However since the 1980s following the aforementioned improved surgical procedures, LITBILD, occurring many years after uneventful surgery, has become an emergent phenomenon observed by many other authors [8,15,17–20].

The main causes of LITBILD are progressive zonular disintegration and capsular shrinkage [8,15,21–23] with PXF – an age related systemic disorder – being the most recognized and common predisposing risk factor [22,24–26]. Pueringer et al. [27] concludes from two studies [28,29] that PXF incidence depends greatly on geographic location and is very common in Sweden, with a “reported prevalence of 18 to 40% in patients undergoing cataract surgery” and “60% to 80% in late IOL dislocations” as found in two additional studies [13,30]. Here the pathophysiology in PXF patients is multifactorial; the PXF accumulations weaken the zonules at both anchoring points including the zonular lamella [17,31], secondly patients are more prone to capsular shrinkage and thirdly PXF patients exhibit increased elastinolysis which weakens the zonules [21] . Other risk factors for zonular weakness include previous vitreoretinal surgery (VRS) [15,22,25,26,32], myopia

[15,18,22,23,32], uveitis [15,22,25,26,33], retinitis pigmentosa [15,22,26,32,34], trauma [15,22,25,26], and connective tissue disorders [15,22]. Moreover, with age the zonules become increasingly weak and there is also “subclinical damage that is presumed to occur during cataract surgery” according to Davis et al. [25]. A recent long‑term case series presents myopia as the most prevalent risk factor [23] where Fernández et al. proposes the pathomechanism for zonular failure is due to “excessive elongation of the zonular fibers that have to support greater stress than in eyes with normal axial length.”

When LITBILD occurs, management may be difficult and surgical reparation is often necessary [15]. The most common indications for surgery include uncontrolled intraocular pressure (IOP) as well as visual symptoms such as monocular diplopia, reduced visual acuity and halos [15,35,36]. Currently a limited number of studies have been made examining the recent decade where surgical techniques have improved and to date no studies exist looking at the situation in Örebro County, Sweden. Most recent studies reporting cumulative

incidences for LITBILD are based on population estimates rather than following a specific cohort. As highlighted by Dabrowska et al. [37] “there is no consensus [in literature] on whether there is an increasing trend of incidence.” However, the study by Dabrowska et al. [37] in Värmland County, Sweden shows that there is an increasing trend and suggests that

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7 further research is needed. Future studies identifying the cumulative risk for cohorts who underwent cataract surgery using current surgical techniques and describing risk factors would therefore be beneficial. This study examined patients who underwent cataract surgery in 2003 at the Eye clinic at Örebro University Hospital. Firstly, this year was selected as it gave possibility for a 15 year follow up span in order to identify LITBILD. Furthermore, in the recent study by Dabrowska et al. [37] it was shown that the cumulative risk for LITBILD did not increase after 10 years from cataract surgery. Secondly, as previously mentioned, cataract surgery using phacoemulsification through a small corneal incision has been used in 99% of cases since 2002. Thus, examining the year 2003 would reflect the most current and common surgical techniques for cataract surgery.

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2 Aim

The primary objective is to determine the 15-year cumulative risk of LITBILD after standard cataract surgery performed in 2003 in Örebro and describe possible risk factors causing LITBILD.

3 Method and Materials

This study was performed as a retrospective nested case-control study (Figure 1) looking at patients who underwent cataract surgery in 2003 at the Eye clinic at Örebro University Hospital (USÖ). This group was found using the operation code CJE20: Phacoemulsification with implantation of lens prostheses in the posterior capsule.

Figure 1 - Nested case-control study design (own illustration)

3.1 Search terms and statistical methods

In order to locate patients within that group who sustained LITBILD within a fifteen year follow-up time period ICD10 diagnosis codes relating to LITBILD were used ranging from year 2003-2018. These included; H27.1 Dislocation of lens, T85.2 Mechanical complication of intraocular lens, as well as a clinical record for quality-control of posterior segment surgery encompassing; secondary lens prostheses implantation, dislocation of lens and iris reconstructive surgery. Postoperative dislocation after 3 months was defined as long term consistent with previous literature. The medical records of these patients where

reviewed individually. Preoperative data including age, sex, dates for surgery, further ocular pathologies like PXF, glaucoma, trauma, and biometric data were collected. Each case was matched with two controls of identical sex and age. These were randomly selected by electronically matching the year of birth and sex through the use of patients’ healthcare-numbers. Significance of risk factors was determined using one tailed Fisher Exact Probability test and calculated using Prism 8 statistics software for MacOS. The same software was used to determine through linear regression, the correlation between age at cataract surgery and time from cataract surgery to LITBILD. Lastly, the Prism 8 statistics software was used for comparison of the axial length (AXL) of eye between the control group and the dislocation group using the one-tailed unpaired t-test.

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3.2 Conditions

Inclusion criteria were; luxation of the entire lens-capsule complex and that luxation was in the same eye as the eye operated in 2003. Excluded were cases in which luxation was directly caused by trauma to eye. Out of the 1499 patients who had cataract surgery in 2003, 23 patients were identified from the two ICD10 code search groups (H27.1 Dislocation of lens and T85.2 Mechanical complication of intraocular lens) and the clinical record for

quality-control group. Thereafter we eliminated 5 duplicates between categories and excluded 9 which did not meet criteria (Figure 2).

Figure 2 - Number of patients analyzed

3.3 Subjects

The subjects were nine adults with LITBILD.

3.4 Ethics

In light of recent literature on LITBILD following cataract surgery which suggests this rare complication is increasing, from a patient safety point of view there seems to be adequate cause to examine these questions further. What we try to evaluate with this study is to identify statistically significant risks involved as well as present real-life cumulative risk data for a specific patient group. Furthermore, in order to depersonalize patient data a code-key was used and patient data was kept on the eye-clinic’s computer.

Provided that this study is classified as experimental work during university education which supports development of the healthcare institution together with provision of

healthcare statistics, the Swedish ethics review act does not apply. This is described in chapter 12 in Swedish government Official Reports (SOU 2014:23) [38].

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4 Results

4.1 Sample Characteristics

The LITBILD group was nine patients out of 1499 operated; five men and four women with median age at LITBILD of 80 years (range 57-82) (Table 1). The median age at cataract surgery was 67 years (range 49-77).

4.2 Time to IOL dislocation

Median time between cataract surgery and LITBILD was 11.2 years or 134 months (range 39-167) and 11 years or 132 months (range 43-168) to reparative operation. The 15-year cumulative risk was 0.6%. Thus 15 15-years after cataract surgery, the percent survival of the implanted IOL was 99.4% (Figure 4). In one case the patient died before reparative surgery was possible which accounts for the lower median time to reparative operation compared to time to LITBILD which was 10.6 years when excluding data from the deceased patient. There was a non-significant negative correlation between patient’s age at cataract surgery and the time between LITBILD (Pearson correlation coefficient, r=1.691; p=0.27) (Figure 3).

Figure 3 - Correlation between age at cataract surgery and time from cataract surgery to in-the-bag IOL dislocation with 95% confidence interval. Calculated using linear regression.

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4.3 Risk factors

As seen in Table 2 the overall occurrence of risk factors was considerably more in the LITBILD group than in the control group. Glaucoma before and/or after cataract surgery and high intraocular pressure before surgery were independently statistically significant risk factors for lens dislocation (Table 2) p<0.05 (95% C.I). 78% of patients with LITBILD had one or more of the risk factors studied whilst the control group represented 40%. AXL of eye showed no significant difference between means in the two groups (p=0.48, 95% C.I) (Figure 5) calculated with one-tailed unpaired t-test with prediction that axial length was greater in LITBILD group. Only one patient in the LITBILD group had myopia, where AXL >26mm.

Figure 4 - Kaplan-Meier analysis, showing percent survival of the implanted intraocular lens after 2003 cataract surgery. Analysis is based on all patients’ being presumed alive 15 years following the procedure. 15-year IOL survival was 99.4%.

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12 Figure 5 - Comparison of axial length of eyes between dislocation group and control group. The

line indicates median value. No significant difference (ns) between means (p=0.48, 95% C.I) calculated with one-tailed unpaired t-test.

4.4 Dislocation configurations

In 44% of cases the IOL capsular bag complex had dislocated inferiorly; in two cases the complex lay against the pupil and in two cases it was dislocated past the pupil. In 33% of cases the IOL-bag complex had dislocated posteriorly deep into the vitreous body, of which one case the IOL had fallen onto the retina. In one case it was superiorly dislocated and tilted causing friction against the posterior side of the iris as well as the anterior facet of the

vitreous body. In one case the complex was dislocated into the anterior chamber.

4.5 Post-dislocation surgery

In seven out of nine LITBILD cases it was decided that complete explantation of the IOL-bag complex was required. Five of these patients received a new posterior IOL with intra-scleral suturing, one received an IOL that was enclaved behind the iris and one patient received an anterior-IOL. In two cases the existing IOL was repositioned with intra-scleral suturing. One case had perioperative choroidal bleeding and in two cases extensive scleral atrophy was seen during surgery.

5 Discussion

The findings of our retrospective nested case-control study demonstrate that the 15-year cumulative risk for LITBILD among patients who underwent cataract surgery in 2003 at the Eye clinic at USÖ was 0.6%. This is slightly lower than a recent study specifically

examining 123 eyes with late ITB dislocation in Värmland County, Sweden, between 1992 and 2012, where the cumulative risk 10, 15, and 20 years after cataract surgery was 0.55%,

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13 1.00% and 1.00% respectively. Furthermore, the 10-year cumulative risk was found to be greater for eyes operated on during 2002-2012 than the previous decade; 0.89% versus 0.39%, (p<.001) [37]. The authors propose that cataract surgery, although safer, is currently offered to more complex cases that are more susceptible to LITBILD and would not have been eligible in the past [37]. In our study, all of the patients with LITBILD had

uncomplicated cataract surgery in contrast to a recent study by Kepste et al [11] where 20% of patients with LITBILD had complicated cataract surgery. 22% of the LITBILD patients in our study had zonular laxity before cataract surgery compared to 35.3% of patients in the study by Kepste et al. [11]. These same patients in our study received capsular tension ring (CTR) implants, which are routinely used in cases with zonular weakness to prevent zonular loss during surgery [30] even though there is no proof that their use later prevents LITBILD [22] nor avoids capsule shrinkage [15,39]. However, CTRs “often facilitates IOL fixation and repositioning” in the future following dislocation as discussed by Jakobsson et al. [10]. In our study, of the two LITBILD patients with CTRs, refixation of the IOL with scleral suturing was performed on one patient and explanation of the whole IOL capsular bag complex on the other. Furthermore, interestingly in our study it was decided in 78% of LITBILD cases that complete explantation of the IOL-bag complex was required. This stands in contrast to a large study examining surgical management of dislocated IOLs, out of which 87.9% dislocation cases where LITBILD, where only 3.3% of IOLs were exchanged [26].

The median age at cataract surgery of the LITBILD group of our study was 67 years (range 49-77) which is young considering the average age among the 2003 total cataract operation group which was 76 years. Likewise, according to the 2003 Swedish National Cataract Register (NCR) Annual report [40], cataract patients younger than 70 years at time of surgery represented only 21 % whilst in our study they represented 67% in the LITBILD group. This matches a previous study by Fujikawa [17] where the mean age at cataract surgery in the LITBILD group (n=36) was 57 years ±14. Although not statistically

significant, as seen in Figure 3 we saw a negative correlation between patients age at cataract surgery and time from cataract surgery to LITBILD. A similar correlation that was

statistically significant was found in the study by Kepste et al [11]. The above makes sense given that several studies suggest that older age at cataract surgery may increase the risk for zonular disintegration and capsular shrinkage both of which cause shorter intervals to LITBILD [11,19,22,34]. The median time between cataract surgery and LITBILD was 11.2 years (10.6 years when excluding deceased patient) and 11 years to reparative operation. Several other reports have also shown a mean time interval of around 8 years from cataract surgery to reparative operation [3,13,19,22,25].

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14 The presence of PXF is the most recognized risk factor in literature relating to

LITBILD [22,24–26] and although not statistically significant between the LITBILD group and the control group in our study the difference in occurrence was 33% vs 5.5%

respectively. PXF syndrome, which is more common in Scandinavia and the Mediterranean region compared to the rest of the world, consists of deposition of protein-like material in the anterior chamber, most notably on the anterior lens capsule [31]. Liu et al. [41] have in a study from 2015 analyzing the capsular bags of LITBILD patients, demonstrated that the presence of PXF is much larger than what had been diagnosed earlier due to significant clinical underdiagnosis. An important contributing factor to this is that following standard procedure with capsulorhexis during cataract surgery, it is very difficult to clinically detect PXF material thereafter, leading to “many cases going unnoticed until well advanced” as discussed by Francisco et al. [42]. Apart from the previously discussed damage to the zonula, PXF accumulations are also known to be deposited in the trabecular meshwork which “can result in aqueous outflow obstruction, raised intraocular pressure (IOP) and glaucoma” according to Khawaja et al. [43]. This is interesting given that in our study glaucoma before and/or after cataract surgery and high IOP before surgery in our study were independently statistically significant risk factors for LITBILD (Table 2) p<0.05 (95% C.I). A similar study also found glaucoma to be present in a large proportion of LITBILD patients 45.7% (n=37 eyes) [44]. The same authors found a significant association between glaucoma and

downward decentration of IOLs in PXF eyes. In fact pseudoexfoliative glaucoma is seen in up to 50% of eyes with PXF and pseudoexfoliative glaucoma is the most common form of secondary open angle glaucoma [43]. We hypothesize that underdiagnosed PXF could be the underlying association between a large proportion of glaucoma in our LITBILD group. In addition, in another study Jakobsson et al. [26] suggests there are indications that IOL dislocation might “in itself cause increased IOP at least in patients with susceptibility to glaucoma.” Here the authors speculate that dislocated IOLs could cause changes in the anterior segment of the eye which lead to “disturbed aqueous flow and cause high IOP” [26].

Furthermore, we find it noteworthy that the patient in our study with the shortest time interval until LITBILD (3 years) had both a CTR and PXF whilst the time intervals for patients with only one of those risk factors had intervals between 11 and 14 years.

Noteworthy in this study was that AXL of eye showed no significant difference between means in the two groups (p=0.48, 95% C.I) (Figure 5) when compared to previous literature as discussed in the introduction where myopia in one study was found to be the most prevalent risk factor for LITBILD [3]. In our study, only one patient in the LITBILD

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15 group had myopia, where AXL >26mm. In that particular case the time from cataract surgery to LITBILD was 6 years which is much shorter than the median.

One weakness in our study was the fact that we did not account for patients who might have had LITBILD but moved to another region or sought medical care from a private provider. Thus there is a possibility that there were more cases of LITBILD which would in that case increase the calculated 15-year cumulative risk. Another limitation of this study is its retrospective form and that all surgeries were performed in 2003 where data on

preoperative ocular risk factors may not have been fully identified or meticulously reported. This could be an explanation, together with the small patient group, that only two risk factors were significant. Moreover, these two risk factors, namely high IOP and glaucoma are clinically easy to identify and are routinely monitored and documented.

6 Conclusion

Patients who underwent cataract surgery in 2003 had a cumulative risk of 0.6% to develop LITBILD within 15 years from cataract surgery. 78% of patients with LITBILD had one or more of the risk factors studied whilst the control group represented 40% (p=0.08). Glaucoma before and/or after cataract surgery and high IOP before surgery were significant risk factors for LITBILD, p<0.05 (95% CI). More future studies that examine larger patient groups and cohorts from different years of cataract surgery are needed to draw more

definitive conclusions. Provided that the level of complexity of cataract surgery is brought up as a likely risk factor for LITBILD we also recommend that surgeons more systematically document the degree of complexity of cataract surgery.

7 Acknowledgements

I would like to give special thanks to my supervisor Sven Crafoord, MD PhD, Department of Ophthalmology, USÖ: Firstly, for your enthusiasm for the subject, sharing experiences from the clinic and thereby spurring my interest and understanding for the subject. Secondly, for your and your team’s support in the data collection process, allowing us to have several discussions in your busy operative schedules on sometimes very technical data. Thirdly, for your feedback and guidance, which was of great value to me when

producing this study. I would also like to thank Eva Karlsson MD, Department of

Ophthalmology, USÖ for your valued discussions about pseudoexfoliations and its complex role in late in-the-bag lens dislocation.

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8 References

[1] Sharma KK, Santhoshkumar P. Lens aging: Effects of crystallins. Biochim Biophys Acta BBA - Gen Subj 2009;1790:1095–108. doi:10.1016/j.bbagen.2009.05.008. [2] Kretz F, Sibylle S, Auffarth G. A Brief History of IOL Materials. The Ophthalmologist

2014. https://theophthalmologist.com/subspecialties/a-brief-history-of-iol-materials (accessed February 25, 2019).

[3] Fernández-Buenaga R, Alió JL. Intraocular Lens Explantation After Cataract Surgery: Indications, Results, and Explantation Techniques. Asia-Pac J Ophthalmol Phila Pa 2017;6:372–80. doi:10.22608/APO.2017181.

[4] Behndig A, Lundström M, Irene S, Montan P, Kugelberg M, Nilsson I, et al. Annual report 2017 based on data from the National Cataracts Registry (Nationella

Kataraktregistret) n.d.

[5] Bowling B, Kanski JJ. Kanski’s clinical ophthalmology: a systematic approach. 8. ed. S.l.: Elsevier; 2016.

[6] Prajna NV, Ravilla TD, Srinivasan S. Cataract Surgery. In: Debas HT, Donkor P, Gawande A, Jamison DT, Kruk ME, Mock CN, editors. Essent. Surg. Dis. Control Priorities Third Ed. Vol. 1, Washington (DC): The International Bank for

Reconstruction and Development / The World Bank; 2015.

[7] Grimfors M, Mollazadegan K, Lundström M, Kugelberg M. Ocular comorbidity and self-assessed visual function after cataract surgery. J Cataract Refract Surg

2014;40:1163–9. doi:10.1016/j.jcrs.2013.11.033.

[8] Drolsum L, Ringvold A, Nicolaissen B. Cataract and glaucoma surgery in

pseudoexfoliation syndrome: a review. Acta Ophthalmol Scand 2007;85:810–21. doi:10.1111/j.1600-0420.2007.00903.x.

[9] Dick HB, Augustin AJ. Lens implant selection with absence of capsular support. Curr Opin Ophthalmol 2001;12:47–57.

[10] Jakobsson G. On Complications to Cataract Surgery. 2015.

[11] Krėpštė L, Kuzmienė L, Miliauskas A, Janulevičienė I. Possible predisposing factors for late intraocular lens dislocation after routine cataract surgery. Med Kaunas Lith

2013;49:229–34.

[12] Foster A. Cataract and “Vision 2020—the right to sight” initiative. Br J Ophthalmol 2001;85:635–7. doi:10.1136/bjo.85.6.635.

[13] Jakobsson G, Zetterberg M, Lundström M, Stenevi U, Grenmark R, Sundelin K. Late dislocation of in-the-bag and out-of-the bag intraocular lenses: Ocular and surgical characteristics and time to lens repositioning. J Cataract Refract Surg 2010;36:1637–44. doi:10.1016/j.jcrs.2010.04.042.

[14] Chang DF. Prevention of bag-fixated IOL dislocation in pseudoexfoliation. Ophthalmology 2002;109:1951–2.

[15] Gimbel HV, Condon GP, Kohnen T, Olson RJ, Halkiadakis I. Late in-the-bag

intraocular lens dislocation: Incidence, prevention, and management. J Cataract Refract Surg 2005;31:2193–204. doi:10.1016/j.jcrs.2005.06.053.

[16] Smith SG, Lindstrom RL. Malpositioned posterior chamber lenses: etiology, prevention, and management. J - Am Intra-Ocul Implant Soc 1985;11:584–91.

[17] Fujikawa A, Mohamed YH, Kinoshita H, Tsuiki E, Kitaoka T. Spontaneous dislocation of the posterior chamber intraocular lens. Int Ophthalmol 2018;38:1111–7.

doi:10.1007/s10792-017-0567-6.

[18] Shigeeda T, Nagahara M, Kato S, Kunimatsu S, Kaji Y, Tanaka S, et al. Spontaneous posterior dislocation of intraocular lenses fixated in the capsular bag. J Cataract Refract Surg 2002;28:1689–93.

(17)

17 [19] Jehan FS, Mamalis N, Crandall AS. Spontaneous late dislocation of intraocular lens

within the capsular bag in pseudoexfoliation patients. Ophthalmology 2001;108:1727– 31.

[20] Kim SS, Smiddy WE, Feuer W, Shi W. Management of Dislocated Intraocular Lenses. Ophthalmology 2008;115:1699–704. doi:10.1016/j.ophtha.2008.04.016.

[21] Davison JA. Capsule contraction syndrome. J Cataract Refract Surg 1993;19:582–9. [22] Gross JG, Kokame GT, Weinberg DV, Dislocated In-The-Bag Intraocular Lens Study

Group. In-the-bag intraocular lens dislocation. Am J Ophthalmol 2004;137:630–5. doi:10.1016/j.ajo.2003.10.037.

[23] Fernández-Buenaga R, Alio JL, Pérez-Ardoy AL, Larrosa-Quesada A, Pinilla-Cortés L, Barraquer R, et al. Late in-the-bag intraocular lens dislocation requiring explantation: risk factors and outcomes. Eye Lond Engl 2013;27:795–801; quiz 802.

doi:10.1038/eye.2013.95.

[24] Hayashi K, Hirata A, Hayashi H. Possible predisposing factors for in-the-bag and out-of-the-bag intraocular lens dislocation and outcomes of intraocular lens exchange surgery. Ophthalmology 2007;114:969–75. doi:10.1016/j.ophtha.2006.09.017.

[25] Davis D, Brubaker J, Espandar L, Stringham J, Crandall A, Werner L, et al. Late in-the-bag spontaneous intraocular lens dislocation: evaluation of 86 consecutive cases. Ophthalmology 2009;116:664–70. doi:10.1016/j.ophtha.2008.11.018.

[26] Jakobsson G, Zetterberg M, Sundelin K, Stenevi U. Surgical repositioning of intraocular lenses after late dislocation: complications, effect on intraocular pressure, and visual outcomes. J Cataract Refract Surg 2013;39:1879–85. doi:10.1016/j.jcrs.2013.06.023. [27] Pueringer SL, Hodge DO, Erie JC. Risk of Late Intraocular Lens Dislocation After

Cataract Surgery, 1980–2009: A Population-Based Study. Am J Ophthalmol 2011;152:618–23. doi:10.1016/j.ajo.2011.03.009.

[28] Mönestam E, Kuusik M, Wachtmeister L. Topical anesthesia for cataract surgery: a population-based perspective. J Cataract Refract Surg 2001;27:445–51.

[29] Ekström C, Alm A. Pseudoexfoliation as a risk factor for prevalent open-angle glaucoma. Acta Ophthalmol (Copenh) 2008;86:741–6. doi:10.1111/j.1755-3768.2008.01248.x.

[30] Mönestam EI. Incidence of Dislocation of Intraocular Lenses and Pseudophakodonesis 10 Years after Cataract Surgery. Ophthalmology 2009;116:2315–20.

doi:10.1016/j.ophtha.2009.05.015.

[31] Conway RM, Schlötzer-Schrehardt U, Küchle M, Naumann GOH. Pseudoexfoliation syndrome: pathological manifestations of relevance to intraocular surgery. Clin Experiment Ophthalmol 2004;32:199–210. doi:10.1111/j.1442-9071.2004.00806.x. [32] Matsumoto M, Yamada K, Uematsu M, Fujikawa A, Tsuiki E, Kumagami T, et al.

Spontaneous dislocation of in-the-bag intraocular lens primarily in cases with prior vitrectomy. Eur J Ophthalmol 2012;22:363–7. doi:10.5301/ejo.5000046.

[33] Brilakis HS, Lustbader JM. Bilateral dislocation of in-the-bag posterior chamber intraocular lenses in a patient with intermediate uveitis. J Cataract Refract Surg 2003;29:2013–4.

[34] Hayashi K, Hayashi H, Matsuo K, Nakao F, Hayashi F. Anterior capsule contraction and intraocular lens dislocation after implant surgery in eyes with retinitis pigmentosa. Ophthalmology 1998;105:1239–43. doi:10.1016/S0161-6420(98)97028-2.

[35] Lim MC, Doe EA, Vroman DT, Rosa RH, Parrish RK. Late onset lens particle glaucoma as a consequence of spontaneous dislocation of an intraocular lens in pseudoexfoliation syndrome. Am J Ophthalmol 2001;132:261–3.

[36] Masket S, Osher RH. Late complications with intraocular lens dislocation after

capsulorhexis in pseudoexfoliation syndrome. J Cataract Refract Surg 2002;28:1481–4. [37] Dabrowska-Kloda K, Kloda T, Boudiaf S, Jakobsson G, Stenevi U. Incidence and risk

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18 1992 and 2012. J Cataract Refract Surg 2015;41:1376–82.

doi:10.1016/j.jcrs.2014.10.040.

[38] Sverige, Utredningen om rätt information i vård och omsorg. Rätt information på rätt plats i rätt tid: slutbetänkande. Stockholm: Fritze; 2014.

[39] Moreno-Montañés J, Sánchez-Tocino H, Rodriguez-Conde R. Complete anterior capsule contraction after phacoemulsification with acrylic intraocular lens and endocapsular ring implantation. J Cataract Refract Surg 2002;28:717–9.

[40] Lundström M, Stenevi U, Thorburn W. Annual report 2003 based on data from the National Cataracts Registry (Nationella Kataraktregistret) n.d.

[41] Liu E, Cole S, Werner L, Hengerer F, Mamalis N, Kohnen T. Pathologic evidence of pseudoexfoliation in cases of in-the-bag intraocular lens subluxation or dislocation. J Cataract Refract Surg 2015;41:929–35. doi:10.1016/j.jcrs.2014.08.037.

[42] Ascaso FJ, Huerva V, Grzybowski A. Epidemiology, Etiology, and Prevention of Late IOL-Capsular Bag Complex Dislocation: Review of the Literature. J Ophthalmol 2015;2015:1–7. doi:10.1155/2015/805706.

[43] Khawaja A, Salim S. Pseudoexfoliative Glaucoma - EyeWiki n.d.

https://eyewiki.org/Pseudoexfoliative_Glaucoma (accessed May 7, 2019).

[44] Østern AE, Sandvik GF, Drolsum L. Late in-the-bag intraocular lens dislocation in eyes with pseudoexfoliation syndrome. Acta Ophthalmol (Copenh) 2014;92:184–91.

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Populärvetenskaplig sammanfattning av vår studie

Vid operation för gråstarr i ögon tar man ut den grumliga linsen och sätter in en artificiell plastlins i den befintliga kapselpåsen i ögat. Man har sett att hela denna påse tillsammans med linsen (sen lins-påse-lossning) kan lossna så sent som 10-15 år efter gråstarrsoperationen. Senaste forskningen tyder på att det finns en ökande trend i förekomsten av sen lins-påse-lossning, vilket enligt vissa författare beror på att gråstarrskirurgi, även om det är säkrare nuförtiden, i nuläget erbjuds till mer komplicerade fall som är mer benägna att få lossning av påsen inklusive linsen och inte skulle ha varit berättigade till gråstarrskirurgi förr i tiden. Vår studie bidrar med en ny typ av forskning inom detta område, bland annat på sådana mer komplexa fall. Vår studie har undersökt patienter som blivit gråstarrsopererade år 2003 vid Örebro Universitetssjukhus, följt de till och med år 2018 och funnit att den 15-åriga

kumulativa risken för sen lins-påse-lossning är 0.6%. Statistiskt signifikanta riskfaktorer för lins-påse-lossning var grönstarr före och/eller efter gråstarrskirurgi samt högt tryck inuti ögat före operationen. Vi har skäl att tro att dessa riskfaktorer är förknippade med

exfoliationssyndrom, ett vanligt tillstånd i Skandinavien där man får fjällning på linsens främre yta, vilket enligt litteratur och ögonläkare ofta är svårt att identifiera efter

gråstarrsoperationer. Tidigare forskning har visat att exfoliationssyndrom är vanligt

förekommande i sjukdomsprocessen för sen lins-påse-lossning men troligtvis är mörkertalet stort för den diagnosen.

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20 Dear Editor of the Journal of Cataract and Refract Surgery,

Enclosed you will find our manuscript entitled “Late in-the-bag intraocular lens dislocation after cataract surgery – a 15 Year follow up study at Örebro University Hospital between 2003 and 2018.”

In a retrospective nested case-control study examining patients who underwent cataract surgery in 2003 at the Eye clinic at Örebro University Hospital we have investigated the 15-year cumulative risk of late in-the-bag intraocular-lens dislocation (LITBILD) and described possible risk factors. Recent literature suggests there is an increasing occurrence of LITBILD, which according to some authors is due to the fact that cataract surgery, although safer, is currently offered to more complex cases that are more susceptible to dislocation and would not have been eligible in the past. Our study provides new research, including such complex cases. Our study shows that the 15-year cumulative risk to develop LITBILD was 0.6% and that independently statistically significant risk factors for LITBILD were glaucoma before and/or after cataract surgery and high intraocular pressure before surgery. We have reasons to believe that these risk factors are associated with pseudoexfoliation, a common disorder in Scandinavia, which according to literature and practitioners is often difficult to identify following cataract surgery and therefore often goes underdiagnosed. Previous research has shown that pseudoexfoliation is common in the pathogenesis of LITBILD and glaucoma in cataract patients.

We hope that you will considerer publishing our manuscript in your journal.

Sincerely,

Diedrik Svanström, MB School of Medical Sciences Örebro University, Sweden

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Etiskt Resonemang

Vetenskapliga studier beträffande sen lins-påse-dislokation (SLPD) efter kataraktoperation tyder på att komplikationen ökar. Det finns därför anledning ur ett

patiententsäkerhetsperspektiv att undersöka riskfaktorerna ytterligare.

Denna studie är en del av kvalitetssäkringsarbetet vid Ögonkliniken på USÖ i Örebro. Studien medförde att patienters journaler granskades noggrant och eftersom antalet som fick SLPD vara ganska få finns det risk att vårdpersonal och familjer, trots att all individuell patientinformation var avidentifierad, kan koppla resultat för gruppen till specifika individer. Även om en viss identifieringsrisk föreligger, samt att patienter ej kunde lämna samtycke till att delta i studien, vilket står emot den etiska principen om autonomi, bör den potentiella nyttan med studien anses överväga riskerna.

Vidare finns det ett etiskt dilemma att inte ges möjlighet att tidigare upptäcka

exfoliationssyndrom hos kataraktpatienter på grund av rådande behandlingsmetoder där man tar bort en stor del av främre kapseln. Ett sätt att minska detta etiska problem är att screena för exfoliationssyndrom innan kataraktoperation samt att årligen kontrollera intraokulärt tryck hos patienter med exfoliationssyndrom. Detta skulle möjliggöra tidigare insättning av behandling samt förebygga sent utvecklad glaukom.

Slutligen finns det etiska dilemman då fler gör refraktiv kirurgi i privat regi där försäljningsargument och höga priser kan ge en falsk känsla av trygghet avseende

komplikationer. Den privata refraktiva kirurgin som korrigerar presbyopi vid 40-50 års åldern är identisk med kataraktoperationer förutom att man opererar på ett friskt öga. Med en ökad livslängd hos dessa patienter så bör risk för SLPD öka markant och därmed möjligen komma i konflikt med nyttoprincipen.

Late in-the-bag intraocular lens dislocation after cataract surgery – a 15 Yearfollow up study at Örebro University Hospital between 2003 and 2018.