Intraocular Lens Calcifications After (Triple-) Descemet Membrane Endothelial Keratoplasty

Early intraocular lens explantations: 10-year database analysis

BACKGROUND

The aim of this study was to analyze the causes and characteristics of IOL explantation within the first year after primary implantation.

METHODS

In this retrospective, cross sectional database study, a database consisting of over 2500 IOL explants sent from 199 national and international doctors over the past 10 years was analyzed. All IOLs explanted within the first year after implantation were included in this analysis. Explants with insufficient information as well as phakic and Add-on IOLs were excluded. Main outcome measures were the reason for explantation, the time between implantation and explantation, as well as IOLs' and patients' characteristics. Additionally, the explanted IOLs were microscopically and histologically analyzed, as required.

RESULTS

Of all explanted IOLs from the database, 1.9% (n = 50) were explanted within the first year after implantation. The most frequent reasons for early IOL explantation were IOL dislocation (32%), visual intolerance (26%), opacification (20%), and intraoperative complications (16%). The time between implantation and explantation was the shortest in cases with intraoperative complications (1.5 ± 3.1 days), followed by IOL dislocation (90.9 ± 103.9 days), visual intolerance (98.3 ± 86.5 days), opacifications (253.5 ± 124.0 days) and other indications (249.7 ± 124.0 days). Calcification of hydrophilic IOLs was the main type of opacification (80%). Notably, seven IOLs required immediate intraoperative exchange due to an intraoperative crack in the optic or a torn off haptic.

CONCLUSION

Indications for early IOL explantation were IOL dislocation, visual intolerance, opacification, and intraoperative complications. Especially intraoperative damages to the IOL and early calcification show a potential for improvement of affected IOLs and implantation systems.

Descemet membrane endothelial keratoplasty combined with presbyopia-correcting and toric intraocular lenses - a narrative review

Fuchs endothelial corneal dystrophy (FECD) is the leading indication for EK and may coexist with cataract and presbyopia. Notably, the outcomes of phacoemulsification in FECD patients are not as favorable as those in eyes without this condition. Historically, only monofocal intraocular lenses (IOLs) were recommended for these patients. However, recent reports have described the implantation of Premium-IOLs (such as Multifocal IOLs, Enhanced Depth of Focus IOLs, and Toric IOLs) in FECD eyes undergoing cataract surgery and Descemet membrane endothelial keratoplasty (DMEK). While the results are encouraging, they are not as optimal as those from unoperated eyes, especially when comparing simultaneous procedures to sequential ones. It's advised to perform the DMEK first to improve the accuracy of IOL calculations. Still, even successfully operated eyes may experience secondary graft failure or graft rejection after DMEK. The success rate of a secondary DMEK is typically lower than that of the initial procedure. Furthermore, if the postoperative thickness after DMEK is less than anticipated, laser enhancements might not be an option. There's a pressing need for more controlled and randomized clinical trials to ascertain the safety and effectiveness of Premium-IOLs for FECD eyes. This narrative review aims to collate evidence on the use of Premium IOL technologies in eyes receiving EK and to underscore key points for surgeons performing EK combined with cataract surgery.

[Hydrophobic surface properties of hydrophilic acrylic lenses do not protect against calcification]

BACKGROUND

Opacification through calcification of hydrophilic acrylic intraocular lenses is a serious complication of cataract surgery, which usually results in explantation of the lens. In the process of calcification, the intraocular lens material plays a crucial role: calcification only occurs in hydrophilic acrylic lenses. Hydrophobic acrylic lenses show no crystal formation within the polymer. Hydrophilic acrylic lenses from some manufacturers have hydrophobic surface properties. The question arises as to what influence these surface properties have on the risk of calcification.

OBJECTIVE

The present study investigated whether the hydrophobic surface properties of hydrophilic acrylic lenses can prevent calcification.

MATERIAL AND METHODS

Using an electrophoretic in vitro model of calcification, two hydrophilic lenses with hydrophobic surface properties were compared to two hydrophilic lenses and a hydrophobic negative control to determine the risk of calcification. The lenses were then analyzed by optical microscopy, Alizarin Red and Von Kossa staining, scanning electron microscopy (SEM) and energy dispersive X‑ray spectroscopy (EDX).

RESULTS

All four hydrophilic lens models showed calcification within the polymer. No difference was found between the hydrophilic lenses and the hydrophilic lenses with hydrophobic surface properties in terms of crystal formation. The hydrophobic negative control showed no calcification.

CONCLUSION

The investigation conducted in this study under standardized conditions could show that hydrophobic surface properties of hydrophilic acrylic lenses do not protect against calcium phosphate crystal formation within the polymer. There also is a risk of calcification in these lens models.

Refractive outcomes after DMEK: meta-analysis

In this meta-analysis and systematic literature review of refractive outcomes after Descemet membrane endothelial keratoplasty (DMEK), the extent of the refractive shift and an overview of reasons for refractive shift after DMEK are provided. The PubMed library was screened for articles containing the terms "Descemet membrane endothelial keratoplasty," "DMEK," "Descemet membrane endothelial keratoplasty combined with cataract surgery," "triple-DMEK" combined with "refractive outcomes," "refractive shift," and "hyperopic shift." The refractive outcomes after DMEK were analyzed and compared using a fixed and random effects model. The overall mean change of the spherical equivalent outcome when compared with the preoperative value in cases of DMEK or when compared with the preoperative target refraction in cases of DMEK combined with cataract surgery was +0.43 diopters (D) (95% CI, 0.31-0.55). When DMEK is combined with cataract surgery, a target refraction of -0.5 D is recommended to achieve emmetropia. Changes in the posterior corneal curvature are identified as the main cause of the refractive hyperopic shift.

Opacification of Hydrophilic Acrylic Intraocular Lenses: Overview of Laboratory Methods for Histological Analysis and Replication of IOL Calcification

Opacification of intraocular lenses (IOLs) due to material changes is a serious complication that can compromise the good visual outcomes of uncomplicated cataract surgery. In hydrophobic acrylic IOLs, opacification can result from glistening formation, while in hydrophilic acrylic IOLs, there is a risk of calcification due to the formation of calcium phosphates within the polymer. Over time, various methods have been developed to investigate calcification in hydrophilic acrylic IOLs. The aim of this article is to provide an overview of standard histological staining and models used to simulate IOL calcification. Histological staining can be used to detect calcification and assess the extent of crystal formation. The development of in vivo and in vitro replication models has helped to identify the underlying pathomechanisms of calcification. In vivo models are suitable for assessing the biocompatibility of IOL materials. Bioreactors as an in vitro model can be used to investigate the kinetics of crystal formation within the polymer. The replication of IOL calcification under standardized conditions using electrophoresis allows for the comparison of different lens materials with respect to the risk of calcification. The combination of different analytical and replication methods can be used in the future to further investigate the pathomechanisms of calcium phosphate crystal formation and the influence of risk factors. This may help to prevent calcification of hydrophilic acrylic IOLs and associated explantation and complications.

Clinical Characteristics of Patients with Intraocular Lens Calcification after Pars Plana Vitrectomy

AIM

To determine the clinical risk factors that may increase the occurrence of intraocular lens (IOL) calcification in patients who had undergone pars plana vitrectomy (PPV).

METHODS

The medical records of 14 patients who underwent IOL explantation due to clinically significant IOL opacification after PPV were reviewed. The date of primary cataract surgery, technique and implanted IOL characteristics; the time, cause and technique of PPV; tamponade used; additional surgeries; the time of IOL calcification and explantation; and IOL explantation technique were investigated.

RESULTS

PPV had been performed as a combined procedure with cataract surgery in eight eyes and solely in six pseudophakic eyes. The IOL material was hydrophilic in six eyes, hydrophilic with a hydrophobic surface in seven eyes and undetermined in one eye. The endotamponades used during primary PPV were C2F6 in eight eyes, C3F8 in one eye, air in two eyes and silicone oil in three eyes. Two of three eyes underwent subsequent silicone oil removal and gas tamponade exchange. Gas in the anterior chamber was detected in six eyes after PPV or silicone oil removal. The mean interval between PPV and IOL opacification was 20.5 ± 18.6 months. The mean BCVA in logMAR was 0.43 ± 0.42 after PPV, which significantly decreased to 0.67 ± 0.68 before IOL explantation for IOL opacification (p = 0.007) and increased to 0.48 ± 0.59 after the IOL exchange (p = 0.015).

CONCLUSIONS

PPV with endotamponades in pseudophakic eyes, particularly gas, seems to increase the risk for secondary IOL calcification, especially in hydrophilic IOLs. IOL exchange seems to solve this problem when clinically significant vision loss occurs.

Intraocular Lens Calcification After Pseudophakic Endothelial Keratoplasty

PURPOSE

To determine the incidence and to document risk factors for intraocular lens (IOL) calcification after pseudophakic endothelial keratoplasty.

METHODS

We retrospectively studied 2700 consecutive penetrating, anterior lamellar and endothelial keratoplasties carried out between December 1992 and June 2022 at the National Eye Hospital, Paris, France.

DESIGN

Retrospective cohort study.

RESULTS

All IOL calcification cases were associated with endothelial keratoplasty. Out of 588 endothelial keratoplasty procedures, 576 eyes were pseudophakic at the end of surgery. Fourteen cases of IOL calcification were observed during follow-up. The cumulative incidence of IOL calcification after endothelial keratoplasty was 4.5%±1.3% at 60 months. Hydrophilic acrylic IOL material (P < .001) and use of SF₆ for anterior chamber tamponade (P = .001) were significantly and independently associated with the cumulative incidence of IOL calcification.

CONCLUSION

The incidence of IOL calcifications seems to be around 5%. Ophthalmologists should avoid hydrophilic acrylic IOLs in patients with endothelial disorders. When the patient already has a hydrophilic IOL, SF₆ should be avoided. The only effective treatment is IOL exchange.

Specifying Risk of Intraocular Lens Opacification After Endothelial Keratoplasty for Different Intraocular Lens Models: A Retrospective Monocentric Cohort Study

PURPOSE

The aims of this study were to calculate the specific risk of opacification for different intraocular lens (IOL) models and to determine whether differences exist, even between lenses made of similar acrylic materials.

METHODS

This is a retrospective cohort study of all patients who underwent endothelial keratoplasty (EK), either after or in conjunction with cataract surgery, from June 2009 to October 2020 at Fundación Jiménez Díaz Hospital.

RESULTS

Three hundred seventy-two eyes of 308 patients with a median follow-up of 856 days [interquartile range (IQR): 384-1570] were included, of which 128 IOLs were hydrophobic, 120 hydrophilic, and 124 unknown. 12.9% of IOLs opacified after a median of 466 days (IQR: 255-743). Visual acuity (VA) was significantly lower in the opacified IOL group [0.51 (IQR: 0.36-1.13)] compared with the nonopacified group [0.22 (IQR: 0.11-0.65)] ( P < 0.001). IOL explantation and exchange was performed in 10 eyes, in which VA improved markedly, from 1.75 (IQR: 0.99-3.00) to 0.60 (IQR: 0.36-0.86) ( P = 0.004). IOL material and opacification events were not independent ( P < 0.001). Significant differences were found between the Akreos ADAPT AO and MI60P models and the Asphina 409M model ( P = 0.022). No significant differences were found in the opacification ratio for hydrophilic IOLs in the clinical diagnosis ( P = 0.11), the type of EK ( P = 0.25), the rebubbling rate ( P = 0.44), or the tamponade used ( P = 0.36).

CONCLUSIONS

Hydrophilic lenses should be avoided in patients at risk of requiring EK. It is important to know the probability of opacification of each IOL model to balance risk and benefits when planning an EK procedure because not all lenses opacify equally. Opacification is an unwanted event with a negative impact on VA, making IOL explantation and exchange the only viable treatment, although one that is not without risks.

Review of Corneal Graft Registries

PURPOSE

Corneal graft registries are organized systems that collect and analyze outcome data (such as long-term graft survival and visual outcomes) after keratoplasty procedures. The aim of this review was to identify existing corneal graft registries and to describe their characteristics.

METHODS

A search of the PubMed database was performed on June 1, 2021, for articles pertaining to corneal graft registries.

RESULTS

The PubMed literature search yielded 958 publications, of which 116 met all the inclusion and exclusion criteria. Among these articles, 15 corneal graft registries were identified, including 6 regional registries, 8 national registries, and 1 multinational registry. This article provides an overview of their characteristics and discusses the main advantages and pitfalls of clinical registries.

CONCLUSIONS

Clinical registry data are increasingly recognized as a valuable tool to monitor corneal transplant outcomes to improve health care services and optimize resource management.

Descemet membrane endothelial keratoplasty: Update on preoperative considerations, surgical techniques, and outcomes

Descemet membrane endothelial keratoplasty (DMEK) is the closest to the physiological replacement of endothelial cells. In the initial years, the technique was surgically challenging. Over the years, with better understanding and modifications in the surgical steps, the technique has evolved as an alternative to more popular procedure Descemet stripping endothelial keratoplasty. The article highlights the various preoperative, intraoperative, and postoperative nuances of DMEK. Additionally, it summarizes the various comparative and noncomparative studies on DMEK outcomes.

Development of a standardized in vitro model to reproduce hydrophilic acrylic intraocular lens calcification

Opacification through calcification of hydrophilic acrylic intraocular lenses (IOL) is a severe complication after cataract surgery. Causing symptoms that range from glare through to severe vision loss, the only effective therapy is explantation of the opacified IOL so far. Although IOL calcification is a well-described phenomenon, its pathogenesis is not fully understood yet. The purpose of the current study was to develop a laboratory model to replicate IOL calcification. Calcification could be reproduced using a horizontal electrophoresis and aqueous solutions of calcium chloride and disodium hydrogen phosphate. The analysis of the in vitro calcified IOLs was performed using light microscopy, Alizarin Red and Von Kossa staining, scanning electron microscopy, energy dispersive x-ray spectroscopy and electron crystallography using transmission electron microscopy and electron diffraction. The presented laboratory model could be used to identify hydrophilic IOLs that are at risk to develop calcification and to assess the influence of associated risk factors. In addition, it can serve as a research tool to further understand this pathology.

Kataraktoperation beim Vorliegen einer Fuchs-Endotheldystrophie

Bei Betroffenen mit einer Fuchs-Endotheldystrophie beginnen die Probleme mit den Augen häufig in einem Alter, in dem sich auch schon erste Anzeichen einer Katarakt zeigen. Und umgekehrt findet man in der augenärztlichen Praxis immer wieder Patient*innen mit einer deutlichen Katarakt und einer Cornea guttata als Nebenbefund. In beiden Situationen stellt sich dann die Frage, ob zunächst nur eine posteriore lamelläre Keratoplastik (in Deutschland meist als DMEK) bzw. nur eine Kataraktoperation erfolgen oder ob gleich ein kombiniertes Vorgehen (sog. Triple-Operation) angestrebt werden sollte. Nur bei jungen Betroffenen mit einer fortgeschrittenen Fuchs-Endotheldystrophie ohne jeglichen Hinweis auf eine Katarakt und gut erhaltener Akkommodation kann, je nach individuellen Gegebenheiten, eine alleinige DMEK sinnvoll sein, in allen anderen Fällen erscheint eine Triple-Operation geeigneter. Dabei erscheint ein sequenzielles Vorgehen in diesen Situationen weniger angebracht, da sich in zahlreichen Studien zeigte, dass der Verlauf und die Ergebnisse nach einer Triple-Operation mit denen nach einem sequenziellen Vorgehen vergleichbar sind. Beim Vorliegen einer signifikanten Katarakt und einer Cornea guttata fällt die Entscheidung im Hinblick auf das operative Vorgehen deutlich schwerer. Hierbei gibt es unterschiedliche Aspekte in der Anamnese sowie den ophthalmologischen Untersuchungen (z. B. zentrale Hornhautdicke, Endothelzelldichte), die einem bei der Entscheidung helfen können. Soll dann zunächst nur eine Kataraktoperation erfolgen, sollten geeignete Maßnahmen ergriffen werden, um ein möglichst optimales Ergebnis trotz Vorliegen der Cornea guttata zu erreichen. Im folgenden Beitrag soll auf die wichtigsten prä-, peri- und postoperativen Aspekte im Hinblick auf die bestmögliche operative Versorgung von Betroffenen mit Fuchs-Endotheldystrophie und Katarakt eingegangen werden.

Cataract surgery and intraocular lens placement in patients with Fuchs corneal dystrophy: a review of the current literature

PURPOSE OF REVIEW

Late-onset Fuchs endothelial corneal dystrophy (FECD) is seen in approximately 4% of individuals over the age of 40. With the growing population of adults over the age of 65, ophthalmologists need to be aware of the preoperative, perioperative, and postoperative considerations involved in cataract surgery in Fuchs patients.

RECENT FINDINGS

Management of cataract patients with FECD requires preoperative assessment of endothelial cell size, density, and morphology. Considerations for perioperative endothelial cell loss include patients with hyperopia and shallow anterior chambers, phacoemulsification technique, transfer of ultrasonic energy to the cornea, corneal-protective perioperative agents, as well as thermal and mechanical damage.

SUMMARY

Ophthalmologists performing cataract surgery on patients with FECD must carefully consider the risks of endothelial cell loss during surgery and minimize the risk of corneal decompensation after surgery. Preoperative management should evaluate the severity of the FECD as well as individual factors such as cataract density, the health and thickness of the cornea, and the anterior chamber depth. Perioperative techniques, adjustments to biometry calculations, and intraocular lens (IOL) selection may help optimize visual outcomes and recovery time.

Descemet's Membrane Endothelial Keratoplasty and Phacoemulsification: Combined versus Sequential Surgery

Purpose:

To compare the outcomes of Descemet's membrane endothelial keratoplasty (DMEK) combined with phacoemulsification versus DMEK following phacoemulsification.

Methods:

In this interventional retrospective comparative nonrandomized case series study, patients with Fuchs endothelial corneal dystrophy (FECD) with either cataract or previous cataract surgery with intraocular lens (IOL) implantation were assigned to one of the two groups according to lens status. Group 1 included patients who had cataract and FECD and would undergo triple procedure (phacoemulsification with IOL implantation and DMEK), whereas Group 2 included patients who had FECD and had phacoemulsification with IOL implantation earlier and would undergo DMEK only as a sequential procedure.

Results:

Postoperative best corrected visual acuity (BCVA) in both groups at 1 week, 1 month, 3 months, and 6 months revealed a statistically nonsignificant difference between the two groups with mean logMAR BCVA at 6 months of 0.07 ± 0.18 and 0.07 ± 0.19 in Group 1 and Group 2, respectively (P > 0.05). The drop in endothelial cell density by the end of the 6^th postoperative month was by 39.44% ±7.92 and 38.73% ±8.10 in the triple-procedure group and DMEK only group, respectively (P = 0.005). Total postoperative complications rate and the rebubbling rate were statistically similar between both groups with 13.5% and 12.5% rebubbling rate in Group 1 and Group 2, respectively (P > 0.05).

Conclusion:

Visual outcomes, endothelial cell loss, and rebubbling rate are comparable when DMEK is combined with phacoemulsification or when it is performed as staged procedure, without statistically significant difference in the outcomes.

Outcomes of Pseudophakic, Phakic, and Triple DMEK

PURPOSE

To evaluate the outcome of phakic and pseudophakic eyes treated by Descemet membrane endothelial keratoplasty (DMEK) versus DMEK combined with cataract surgery (triple DMEK).

METHODS

Retrospective cohort study based on the prospective Cologne DMEK data base. This study is a single-center analysis of 62 eyes undergoing phakic (age mean ± SD 52 ± 6.43), 518 eyes undergoing pseudophakic (73.5 ± 8.57), and 557 eyes undergoing triple DMEK (67.93 ± 8.57). Outcome measures were changes in best spectacle-corrected visual acuity (BSCVA), central corneal thickness, endothelial cell density (ECD), rebubbling rates within the first year after surgery, and the need for cataract surgery within the first 2 years after phakic DMEK.

RESULTS

The preoperative BSCVA (mean ± SD; logarithm of the minimum angle of resolution) was 0.30 ± 0.22 in the phakic, 0.63 ± 0.45 in the pseudophakic, and 0.44 ± 0.30 in the triple DMEK group (P < 0.001), which changed to 0.09 ± 0.12, 0.14 ± 0.1, and 0.1 ± 0.1 (P < 0.001) 1 year after surgery, respectively. There was no difference in central corneal thickness (P = 0.929) and endothelial cell density (P = 0.606) 1 year postoperatively. Rebubbling rates in DMEK using SF6 20% for anterior chamber tamponade were not significantly different (P = 0.839). After phakic DMEK, 40% of eyes underwent cataract surgery within the second year. However, there was a high loss to follow-up in this group.

CONCLUSIONS

Phakic and triple DMEK procedures tend to have a better 1-year BSCVA than pseudophakic DMEK, with no differences in all other parameters analyzed. However, patients from the pseudophakic DMEK group were older and already had worse BSCVA before surgery.

Microscopic Characteristics of Late Intraocular Lens Opacifications

CONTEXT.—

The increases in overall life expectancy and in lens surgeries performed on younger patients have resulted in a significant increase in the anticipated duration of artificial intraocular lenses (IOLs) in the eye. Thus, the physicochemical properties of the IOL become a critical issue, and several types of postoperative IOL opacifications have been reported.

OBJECTIVE.—

To describe the microscopic characteristics of opacified IOLs. Glistenings and subsurface nanoglistenings are fluid-related phenomena developing mainly in hydrophobic acrylic IOLs and are associated with aqueous influx into the IOL matrix. Calcification presents in hydrophilic acrylic or silicone IOLs as deposits of hydroxyapatite or other phases of calcium. Snowflake degeneration is less common, and it manifests in older polymethyl methacrylate IOLs.

DATA SOURCES.—

PubMed and ScienceDirect databases were searched for the following keywords: intraocular lens, IOL, cataract surgery, phacoemulsification, opacification, glistening, subsurface nanoglistenings, calcification, snowflake degeneration. English-language articles published up to October 15, 2019 were included in the study. The manuscript contains mainly a literature review; however, it was supplemented with original investigations from the David J. Apple International Laboratory for Ocular Pathology.

CONCLUSIONS.—

Glistenings and subsurface nanoglistenings should be evaluated in a hydrated state and at room temperature; they manifest as microvacuoles sized from 1.0 to greater than 25.0 μm and less than 200 nm, respectively. Calcification deposits are situated on or underneath the surface of the IOL and can be stained with a 1% alizarin red solution or with the von Kossa method. Snowflake degeneration manifests as "particles" or "crystals," causing whitish IOL discoloration. Scanning electron microscopy or energy dispersive X-ray spectroscopy may improve the diagnostic accuracy.

A Novel Approach for Assessing Visual Impairment Caused by Intraocular Lens Opacification: High-Resolution Optical Coherence Tomography

PURPOSE

To quantify in vitro straylight induced by intraocular lens (IOL) localized opacification using an anterior segment optical coherence tomography (OCT) device.

DESIGN

Laboratory investigation.

METHODS

We obtained high-resolution OCT cross-section images of 44 explanted IOLs using a new in vitro application for an anterior segment OCT device, the Anterion (Heidelberg Engineering, Heidelberg, Germany). In 24 cases, the reason for IOL explantation was a centrally localized opacification, the sequela of a secondary ocular surgery. As a control, we used 20 IOLs removed after an IOL (sub-)luxation. Using image analysis, we found a threshold area value representing a metric for the amount of opacification in a region of interest in the IOL's central optic. We used a modified C-Quant straylight meter (Oculus, Wetzlar, Germany) to quantify light scattering. We derived a linear regression from calculating the correlation between the amount of opacification and straylight.

RESULTS

We visualized different amounts of IOL opacification using the OCT device. The opacified lenses showed a mean threshold area of 6.7% ± 3.3% and mean straylight was 95.1 ± 75.6 deg²/sr. The clear group's mean threshold area was 2.0% ± 0.8% and 5.0 ± 3.4 deg²/sr mean straylight. Straylight correlated statistically significantly with the threshold area, with a correlation coefficient of R² = 0.80, P < .001.

CONCLUSIONS

This high-resolution OCT imaging technique can be used to visualize IOL opacities. The amount of opacification correlated well with the straylight induced by the lens. Anterior segment OCT imaging might be used in the future as a tool for predicting the extent of visual impairment and aid clinicians to quantify patients' complaints.

Effects of uncomplicated Descemet membrane endothelial keratoplasty on the central retinal thickness

Purpose

To determine retinal thickness (RT) changes and the incidence of macular edema after uncomplicated Descemet membrane endothelial keratoplasty (DMEK-ME) in patients without ME risk factors.

Methods

In this retrospective study, 107 pseudophakic eyes of 74 patients with Fuchs endothelial dystrophy (FED) (79.4%) or bullous keratopathy (BK) (20.6%) underwent DMEK surgery between 2016 and 2019 at the Department of Ophthalmology, RWTH Aachen University. Patients with intra- or postoperative complications as well as pre-existing risk factors for ME were excluded. Macular spectral-domain optical coherence tomography (SD-OCT) and best spectacle-corrected visual acuity (BSCVA) measurements were performed before, 1 week, 1 month, and 6 months after surgery. Retinal thickness (RT) was analyzed in the central foveal 1 mm (CSF), parafoveal 3 mm and 6 mm subfield.

Results

Eight eyes (7.5%) developed DMEK-ME 1 month after surgery. Six DMEK-ME eyes (75%) were rebubbled, compared with 31.3% (31 of 99; P = 0.02) of the non DMEK-ME eyes. DMEK-ME eyes had a significantly thicker CSF 1 month after surgery (432.0 ± 97.6 μm) compared with non-DMEK-ME eyes (283.7 ± 22.2 μm; P = 0.01). The other subfields and time points showed no significant RT changes. DMEK-ME significantly impaired BSCVA (0.38 ± 0.92 logMAR) only 1 month after surgery in comparison to the non DMEK-ME eyes (0.23 ± 0.87 logMAR, P = 0.015).

Conclusion

Excluding systemic and surgery-related risk factors, rebubbling increases the risk of DMEK-ME. Performing a CSF scan 1 month after surgery, particularly in rebubbled eyes, efficiently detects DMEK-ME and allows the prompt initiation of treatment, e.g., topical corticosteroid and non-steroidal (NSAID) eye drops.

[Opacification of Intraocular Lenses]

The spectrum of complications in the use of intraocular lenses (IOL) is different today from at the time of their introduction. Opacities in the IOL material are increasingly described in the literature as a reason for IOL explantation. This paper provides an overview of the different forms of IOL material opacities. Currently relevant forms of IOL material opacities and their effects on optical quality are summarized. The main reason for opacification in hydrophilic IOLs is calcification, whereas in hydrophobic IOLs it is mainly the formation of so-called glistenings that is reported. Most material opacities affect various optical parameters and lead to increased intraocular straylight. In case of a disturbing material opacification, the only therapeutic option is to replace the opacified IOL.

Eintrübung von Intraokularlinsen

Das Spektrum an Komplikationen und die Explantationsgründe bei der Verwendung von Intraokularlinsen (IOL) haben sich durch die Weiterentwicklung der Kataraktchirurgie verändert. Eintrübungen des Materials beeinflussen dabei unterschiedlich stark die optische Qualität. Im Fall einer störenden Eintrübung des Materials ist auch heute noch – trotz aller Fortschritte auf dem Gebiet der IOL-Materialien – ein Austausch der IOL die einzige Behandlungsoption.

A review of late intraocular lens opacifications

PURPOSE OF REVIEW

Phacoemulsification cataract surgery is one of the most commonly performed surgical procedure worldwide. In the majority of cases, intraocular lenses (IOLs) are implanted. Due to the increasing life expectancy and the fact that cataract surgery is performed in earlier stages, the anticipated IOL duration in the eye has increased over the last decades. The aim of this study was to review the types and describe the characteristics of late intraocular lens opacifications.

RECENT FINDINGS

Calcification was the most commonly reported type of opacification in hydrophilic IOLs; it usually negatively impacted the visual function and required IOL explantation. Glistening manifested in hydrophobic acrylic lenses and was frequent in some IOL models. In most cases glistening and subsurface nanoglistenigs do not lead to a decline in visual acuity or require IOL exchange. Current studies indicate that fluid-related phenomena may induce straylight, leading to a decrease of comfort and quality of vision.

SUMMARY

Several reports on late IOL opacifications have been published in recent years. In some cases, particularly in glistening, the development of the opacifications might be related to IOL aging. The influence of the fluid-related microvacuoles on the quality of vision requires further research.

[Opacification of intraocular lenses: laboratory and clinical findings]

Hintergrund

Das Spektrum der Komplikationen beim Einsatz von Intraokularlinsen (IOL) ist heute ein anderes als zur Zeit ihrer Einführung. Trübungen im IOL-Material werden vermehrt als Explantationsgrund in der Literatur beschrieben.

Ziel der Arbeit

Diese Arbeit soll einen Überblick über die verschiedenen Formen von IOL-Materialeintrübungen geben.

Material und Methoden

Die heute relevanten Formen von IOL-Materialeintrübungen und deren Auswirkungen auf die optische Abbildungsqualität wurden zusammengestellt.

Ergebnisse und Diskussion

Als Grund für eine Eintrübung steht bei hydrophilen IOL die Kalzifikation im Vordergrund, während bei hydrophoben IOL v. a. über die Entstehung sog. „Glistenings“ berichtet wird. Die meisten Materialeintrübungen beeinflussen verschiedene optische Parameter und führen zu einem erhöhten intraokularen Streulicht. Im Falle einer störenden Materialeintrübung besteht die einzige Therapieoption in einem Austausch der eingetrübten IOL.

A narrative review of intraocular lens opacifications: update 2020

The opacifications of intraocular lenses (IOLs) can significantly impact patients visual quality. Despite the identification of specific risk factors, manufacturing changes, opacifications are not eliminated. Likewise, more attention in recent studies was paid to possible new risk factors, however one of the most important purposes of the studies remains opacifications effect on visual performance, which could be disturbed in different aspects. The aim of this review is to discuss the main risk factors of IOLs opacification in particular IOL types, and its impact on vision quality. Different risk factors were discussed in the study, including the material of IOLs, the impact of the breakdown of blood-aqueous barrier (BAB), and certain surgeries that can be associated with opacification formation. Glistenings occur more often in a hydrophobic material, however, the changes in water content of the IOLs can significantly reduce the formation of glistenings. The studies showed a significant effect of intraocular injection of exogenous air or gas during Descemet-stripping endothelial keratoplasty, Descemet-stripping automated endothelial keratoplasty, Descemet membrane endothelial keratoplasty, and pars plana vitrectomy on calcification formation. It raises a concern, as the incidence of these surgeries is increasing. Visual acuity decreases significantly after the calcification in IOLs occurs, and it usually causes IOLs exchange. However, disability glare seems to be more affected in patients with IOLs, which were affected by glistenings than visual acuity. Disability glare is associated with increased levels of straylight, which was widely evaluated in recent studies and it was reported to be a susceptible measurement to detect the presence of IOLs pathology. For future researches, it should be noticed that disability glare and straylight are more appropriate in evaluating IOLs opacification effect on visual quality than visual acuity. While reviewing the main risk factors of IOLs opacifications particular attention must be paid on calcification occurrence in hydrophilic acrylic IOLs after surgeries with intraocular injection of exogenous air or gas.

Variation in intraocular lens calcification under different environmental conditions in eyes with supplementary sulcus-supported lenses

Purpose

Analysis of explanted intraocular lenses (IOLs) from pseudophakic eyes with supplementary sulcus-supported IOLs.

Methods

In this laboratory investigation, ten supplementary and capsular bag IOLs were analyzed. All lenses were received between January 2012 and March 2018. Explants were examined morphologically with histological and electron microscopic techniques and patients’ medical history was evaluated. Additionally, we used a technique new to this field: Transmission Electron Microscopy and electron diffraction pattern analysis was performed to investigate the structure of the opacifying crystals in detail.

Results

Eleven lenses were explanted due to IOL opacification from seven polypseudophakic eyes: In three cases the supplementary lens calcified, in three cases the capsular bag IOL (both lenses analyzed) and in one case both IOLs (only the supplementary was received). Additional surgical procedures and comorbidities included pars plana vitrectomy or Descemet stripping endothelial keratoplasty and diabetes mellitus. For each opacified lens, a varying layer of a Calcium phosphate beneath the optic surface was apparent. Crystal characterization revealed its composition to be Hydroxyapatite.

Conclusions and Importance

We report on a series of secondary calcification in lenses explanted from polypseudophakic eyes. In some cases, calcification occurred in the capsular bag lens, in other cases in the supplementary lens, or in both. The severity of the morphological change could be related to the comorbidities and the presence of surgery subsequent to the lens implantations. Detailed morphology of the opacifying crystals was revealed.

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Intraocular lenses exhibited calcification in a series of polypseudophakic eyes.

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Pathology occurred in the capsular bag lens, the supplementary lens, or in both.

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Calcification was associated with different environmental factors.

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Depending on the factor, morphology and pattern of the opacity differed.

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Transmission Electron Microscopy revealed the opacifying crystals' ultrastructure.

Assessment of straylight and the modulation transfer function of intraocular lenses with centrally localized opacification associated with the intraocular injection of gas

PURPOSE

To assess the optical quality of intraocular lenses (IOLs) explanted because of opacification after the intraocular injection of gas.

SETTING

David J. Apple Laboratory, Heidelberg, Germany.

DESIGN

Experimental study.

METHODS

Four hydrophilic acrylic IOLs were studied, each with a centrally localized round opacification pattern associated with the intraocular use of gas. Laboratory analysis included gross examination with a light microscope, followed by alizarin and von Kossa staining. Optical quality was assessed by examining the modulation transfer function (MTF) and straylight. Results were compared with those of a control IOL and normative data for straylight of the crystalline lens. The following parameters were derived from image analysis: opacified surface fraction, light loss in the opacified surface, and the area and number of granules. The relationship between straylight increase and those parameters was studied.

RESULTS

Fine granules were identified on the IOL surface and subsurface. The granules stained positive for calcium, and the MTF levels of 2 IOLs dropped markedly. The other 2 showed relatively minor changes. The straylight was extremely increased in 3 IOLs up to (and above) a level of that of a cataractous lens. A proportional relationship was found between straylight and the morphological parameters from image analysis.

CONCLUSIONS

Intraocular lenses with centrally localized opacification have a strong potential for deteriorating optical performance. However, the optical quality might differ depending on the morphology of opacification. A serious straylight increase was found in most of these IOLs, suggesting that affected patients may suffer from glare-related symptoms.

[10 years of Descemet membrane endothelial keratoplasty in Fuchs endothelial corneal dystrophy : What have we learned?]

BACKGROUND AND OBJECTIVE

Descemet membrane endothelial keratoplasty (DMEK) has increased in popularity since its introduction over 10 years ago. This article presents a summary of the experiences of the past years collected at the Department of Ophthalmology at the University of Cologne.

METHODS

A literature review of DMEK studies primarily from the Department of Ophthalmology at the University of Cologne, Germany was carried out. Own experiences in the fields of donor selection and graft preparation, DMEK surgery, complication management and postoperative treatment are summarized.

RESULTS

Since the introduction of DMEK experience has been gained and ongoing improvements have occurred ranging from donor-recipient allocation to postoperative follow-up. These led to a better reproducibility of the intervention for the surgeon, to a better postoperative result and to a reduction of the complication rate.

DISCUSSION

The DMEK represents a safe and individualized procedure for endothelial transplantation for corneal endothelial dysfunction. Continuing development of the method leads to optimization and safer results.

Immune reactions after modern lamellar (DALK, DSAEK, DMEK) versus conventional penetrating corneal transplantation

In the past decade, novel lamellar keratoplasty techniques such as Deep Anterior Lamellar Keratoplasty (DALK) for anterior keratoplasty and Descemet stripping automated endothelial keratoplasty (DSAEK)/Descemet membrane endothelial keratoplasty (DMEK) for posterior keratoplasty have been developed. DALK eliminates the possibility of endothelial allograft rejection, which is the main reason for graft failure after penetrating keratoplasty (PK). Compared to PK, the risk of endothelial graft rejection is significantly reduced after DSAEK/DMEK. Thus, with modern lamellar techniques, the clinical problem of endothelial graft rejection seems to be nearly solved in the low-risk situation. However, even with lamellar grafts there are epithelial, subepithelial and stromal immune reactions in DALK and endothelial immune reactions in DSAEK/DMEK, and not all keratoplasties can be performed in a lamellar fashion. Therefore, endothelial graft rejection in PK is still highly relevant, especially in the "high-risk" setting, where the cornea's (lymph)angiogenic and immune privilege is lost due to severe inflammation and pathological neovascularization. For these eyes, currently available treatment options are still unsatisfactory. In this review, we will describe currently used keratoplasty techniques, namely PK, DALK, DSAEK, and DMEK. We will summarize their indications, provide surgical descriptions, and comment on their complications and outcomes. Furthermore, we will give an overview on corneal transplant immunology. A specific focus will be placed on endothelial graft rejection and we will report on its incidence, clinical presentation, and current/future treatment and prevention options. Finally, we will speculate how the field of keratoplasty and prevention of corneal allograft rejection will develop in the future.

Corneal Densitometry as a Predictive Diagnostic Tool for Visual Acuity Results After Descemet Membrane Endothelial Keratoplasty

PURPOSE

We sought to investigate correlations between preoperative corneal backscatter with visual acuity results after Descemet membrane endothelial keratoplasty (DMEK) in eyes with corneal endothelial disorders.

DESIGN

Retrospective interventional case series.

METHODS

The first 551 consecutive patients with DMEK at the Center of Ophthalmology, University of Cologne who had available preoperative corneal densitometry values (corneal light backscatter measured in gray scale units) measured with the Scheimpflug-based Oculus Pentacam corneal densitometry module were screened for eligibility. Best spectacle-corrected visual acuity (BSCVA) results were retrospectively correlated with densitometry data. Densitometry data were obtained in 4 corneal layers (ie, anterior, central, posterior, and total layers) and 4 annuli. Pre- and postoperative BSCVA results were correlated with densitometry data. Receiver operating characteristic analyses were performed.

RESULTS

Four hundred twelve eyes were available for the analyses. Visual acuity results improved significantly after DMEK surgery at 3, 6, 12, and 24 months of follow-up (P < .001). Corneal backscatter correlated moderately with preoperative BSCVA results. Moderate associations to postoperative BSCVA results could predominantly be found between densitometry values of the anterior and central layer more pronounced in the center of the cornea for all postoperative timepoints. The posterior layer correlated worst with postoperative gain in BSCVA. Receiver operating characteristic analyses revealed that the best predictive power of densitometry values was for the 2-6 mm annular zone of the cornea.

CONCLUSION

Corneal backscatter in eyes with corneal endothelial disorders correlates with postsurgical BSCVA results after DMEK surgery. Therefore, early DMEK surgery seems to have a positive impact on long-term BSCVA results.

Material Analysis and Optical Quality Assessment of Opacified Hydrophilic Acrylic Intraocular Lenses After Pars Plana Vitrectomy

PURPOSE

Explanted hydrophilic intraocular lenses (IOLs) with clinically significant opacification after pars plana vitrectomy (PPV) were assessed for material change and optical quality, in an in vitro laboratory study.

DESIGN

Retrospective observational case series.

METHODS

Ten opacified IOLs after PPV with intraocular gas injection were analyzed in a laboratory setting. Analyses included evaluation of patients' medical history, optical quality assessment, light microscopy, histologic staining, scanning electron microscopy, and energy dispersive x-ray spectroscopy.

RESULTS

In all 10 IOLs a thin layer of calcium phosphate that had accumulated underneath either the anterior or posterior optical surface in a central circular area of the IOL optic caused the opacification. The calcifications lead to deterioration of the modulation transfer function (MTF) across all spatial frequencies.

CONCLUSION

PPV with instillation of gas into a pseudophakic eye with an acrylic hydrophilic lens seems to increase the risk for secondary calcification irrespective of the manufacturer. In these cases, IOL exchange is the only treatment option available. Since IOL exchange is associated with a high intraoperative complication rate, our results suggest to consider the risk of IOL calcification when implanting hydrophilic acrylic IOLs.

Evolution of Consecutive Descemet Membrane Endothelial Keratoplasty Outcomes Throughout a 5-Year Period Performed by Two Experienced Surgeons

PURPOSE

To assess the evolution of clinical outcomes of more than 1300 Descemet membrane endothelial keratoplasties (DMEKs) alone or in combination with cataract surgery (triple DMEK) throughout a 5-year period at a single center, performed by 2 already experienced DMEK surgeons.

DESIGN

Retrospective trend study.

METHODS

Review of charts between July 2011 and July 2016 at the Department of Ophthalmology, University of Cologne, Germany.

RESULTS

A total of 1340 out of 1340 eyes with sufficient information were included. Six-month and 12-month best spectacle-corrected visual acuity (logMAR) had already reached high levels for the surgeries performed in 2011 (0.10 ± 0.06 and 0.09 ± 0.07, respectively) and did not further improve in later years (P = .272). Likewise, endothelial cell loss (ECL) and central corneal thickness (CCT) reached comparable levels independently of the year of surgery (average 12-month ECL was 38% ± 15% and average 6-month CCT decrease was 19% ± 11%). However, there was a decrease in the rebubbling rate, from 68% in 2011, 67% in 2012, and 70% in 2013 to 53% in 2014, 29% in 2015, and 16% in 2016, which was associated with the introduction of 20% sulfur hexafluoride (SF₆) instead of room air for anterior chamber tamponade in 2015 (n = 986; P < .001). The percentage of severe complications after DMEK surgery also decreased significantly with surgeons' growing experience (P < .001; 95% confidence interval [0.09; 0.12]) over the years.

CONCLUSIONS

After an initial learning curve in DMEK surgery, results of visual acuity and ECL do not seem to further improve. However, the complication rate continuously declines, at least over the subsequent 5-year period analyzed herein.

Combined Cataract/DSEK/DMEK: Changing Expectations

Endothelial keratoplasty (EK) has revolutionized corneal transplant surgery by providing rapid visual recovery and improved visual outcomes. In parts of the world with Fuchs endothelial dystrophy, many patients may present with both cataracts and corneal degeneration requiring surgery. Other forms of endothelial decompensation may also present with cataracts. The staging or combination of transplant surgery and cataract surgery depend on both the abilities of the surgeon and the surgical techniques being considered. We currently use phacoemulsification to remove cataracts and routinely perform both cataract surgery and EK with topical anesthesia. The decision to perform either combined or staged cataract and transplant surgery depends upon the examination of the eye including assessment of the anterior chamber depth and the status of the anterior surface of the cornea, which affects the ability to reliably assess keratometry. Additional considerations include the type of lens implant to use, the desired refractive outcome, and the patient's preference about whether to undergo 1 or 2 surgical procedures per eye.