The potential influence of the ligament of Wieger on the crystalline lens shape

This research uses mathematical modelling to evaluate the influence of the ligament of Wieger on the crystalline lens shape at rest, and during accommodation. An axisymmetric model of the anterior segment, including the ligament of Wieger, was created using the finite element method. Different conditions including variations of stiffness and positions of the ligament, with and without the ligament, were tested to see how they affected lens curvature and optical power. Adding the ligament of Wieger to the simulation had a noticeable impact on the optical power of the lens, particularly on the posterior surface power and total power. Ligament stiffness and width significant influenced the accommodative range of the eye by - 0.95D and - 2.39D for ligaments with the same and 3× the stiffness of the capsular bag, respectively. Ligament width and inner diameter had negligible effects on lens thickness but did have significant effects on posterior surface power and accommodation. In this simulation, we found that the ligament of Wieger can significantly affect the lens shape, both at rest and during accommodation, and may need to be considered in lens models.

Development of machine learning models to predict posterior capsule rupture based on the EUREQUO registry

PURPOSE

To evaluate the performance of different probabilistic classifiers to predict posterior capsule rupture (PCR) prior to cataract surgery.

METHODS

Three probabilistic classifiers were constructed to estimate the probability of PCR: a Bayesian network (BN), logistic regression (LR) model, and multi-layer perceptron (MLP) network. The classifiers were trained on a sample of 2 853 376 surgeries reported to the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO) between 2008 and 2018. The performance of the classifiers was evaluated based on the area under the precision-recall curve (AUPRC) and compared to existing scoring models in the literature. Furthermore, direct risk factors for PCR were identified by analysing the independence structure of the BN.

RESULTS

The MLP network predicted PCR overall the best (AUPRC 13.1 ± 0.41%), followed by the BN (AUPRC 8.05 ± 0.39%) and the LR model (AUPRC 7.31 ± 0.15%). Direct risk factors for PCR include preoperative best-corrected visual acuity (BCVA), year of surgery, operation type, anaesthesia, target refraction, other ocular comorbidities, white cataract, and corneal opacities.

CONCLUSIONS

Our results suggest that the MLP network performs better than existing scoring models in the literature, despite a relatively low precision at high recall. Consequently, implementing the MLP network in clinical practice can potentially decrease the PCR rate.

Anesthesia techniques and the risk of complications as reflected in the European Registry of Quality Outcomes for Cataract and Refractive Surgery

PURPOSE

To determine the trends in anesthesia techniques for cataract surgery over the past decade and their relationship to surgical complications.

SETTING

Clinics affiliated with the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO).

DESIGN

Retrospective cross-sectional register-based study.

METHODS

Variables include patient demographics, visual acuity, ocular comorbidities, surgery characteristics, intraoperative complications, and postoperative complications for the study period from January 2008, to December 2018. The anesthesia methods registered in the EUREQUO and included in the study are topical, combined topical and intracameral, sub-Tenon, regional, and general anesthesia. Multivariate logistic regression models for each complication were constructed to estimate the adjusted odds ratio (OR) and 95% CIs.

RESULTS

Complete data were available of 1 354 036 cataract surgeries. Topical anesthesia increased significantly over time (from 30% to 76%, P < .001). Sub-Tenon and regional anesthesia decreased (from 27% and 38% to 16% and 6%, respectively, P < .001), and general and combined topical and intracameral anesthesia remained stable (around 2%). Sub-Tenon (OR, 0.80; 95% CI, 0.71-0.91, P < .001), regional (0.74; 95% CI, 0.71-0.78, P < .001), general (0.53; 95% CI, 0.50-0.56, P < .001), and intracameral anesthesia (0.76; 95% CI, 0.64-0.90, P = .001) carried a significantly decreased risk of posterior capsule rupture (PCR), with and without dropped nucleus, compared with topical anesthesia. The risk of endophthalmitis was significantly lower with regional anesthesia compared with topical anesthesia (OR, 0.60; 95% CI, 0.44-0.82, P = .001).

CONCLUSIONS

The use of topical anesthesia for cataract surgery increased over time. Topical anesthesia is associated with an increased risk of PCR with and without dropped nucleus, and endophthalmitis.

Wave-like calcification on the posterior surface of an acrylic hydrophilic bag-in-the-lens (BIL) implant

Purpose

To report secondary opacification of a hydrophilic bag-in-the-lens (BIL) which is a rare manifestation that can happen years after initial surgery.

Observations

We describe a case of a prominent wave-like, rippled opacification on the posterior surface of the BIL. The opacification was composed of calcium deposits and seems to start in the periphery as a ring and progresses to the centre of the posterior surface. Due to the specific design of the BIL, there is direct contact between the BIL and the posterior chamber, both with the space of Berger, and the anterior hyaloid, particularly in this very hyperopic eye. Conclusions and importance: Abnormal fluid flow and stagnation in an unusual retrolenticular space is a possible explanation for this unusual pattern of posterior surface opacification.

Outcomes of cataract surgery complicated by posterior capsule rupture in the European Registry of Quality Outcomes for Cataract and Refractive Surgery

PURPOSE

To analyze the outcomes of cataract surgery complicated by posterior capsule rupture (PCR).

SETTING

European clinics affiliated to the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO).

DESIGN

Retrospective cross-sectional register-based study.

METHODS

Data were retrieved from the EUREQUO between January 1, 2008, and December 31, 2018. The database consists of data on demographics, intraoperative complications such as PCR, type of intraocular lens (IOL) material, postoperative refraction, corrected distance visual acuity (CDVA), and postoperative complications.

RESULTS

1 371 743 cataract extractions with complete postoperative data were reported in the EUREQUO. In 12 196 cases (0.9%), PCR was reported. After PCR, patients were more likely to receive a poly(methyl methacrylate) IOL (5.2% vs 0.4%, respectively) or no IOL (1.1% vs 0.02%, respectively) compared with patients without PCR. The refractive and visual outcomes in patients with PCR were significantly worse than in those without PCR (mean CDVA 0.13 ± 0.21 vs 0.05 ± 0.16 logMAR, P < .001; mean absolute biometry prediction error 1.15 ± 1.60 diopters [D] vs 0.41 ± 0.45 D, P < .001). A multivariate linear regression analysis, adjusting for potential explanatory variables, confirmed a statistically significant difference (0.04 logMAR, P < .001, and .70 D, P < .001, respectively). Patients with PCR had significantly more postoperative complications (corneal edema 0.88% vs 0.17%, adjusted odds ratio [aOR], 2.80 95% CI, 2.27-3.45, endophthalmitis 0.11% vs 0.02%, aOR, 4.40 95% CI, 2.48-7.81, uncontrolled intraocular pressure 0.55% vs 0.03%, aOR, 14.58 95% CI, 11.16-19.06, P < .001).

CONCLUSIONS

Patients with PCR had significantly worse visual and refractive outcomes and more postoperative complications than patients without PCR. However, most of these patients achieved better postoperative visual acuity than that preoperatively.

Laser-induced nanobubbles safely ablate vitreous opacities in vivo

In myopia, diabetes and ageing, fibrous vitreous liquefaction and degeneration is associated with the formation of opacities inside the vitreous body that cast shadows on the retina, appearing as 'floaters' to the patient. Vitreous opacities degrade contrast sensitivity function and can cause notable impairment in vision-related quality of life. Here we introduce 'nanobubble ablation' for safe destruction of vitreous opacities. Following intravitreal injection, hyaluronic acid-coated gold nanoparticles and indocyanine green, which is widely used as a dye in vitreoretinal surgery, spontaneously accumulate on collagenous vitreous opacities in the eyes of rabbits. Applying nanosecond laser pulses generates vapour nanobubbles that mechanically destroy the opacities in rabbit eyes and in patient specimens. Nanobubble ablation might offer a safe and efficient treatment to millions of patients suffering from debilitating vitreous opacities and paves the way for a highly safe use of pulsed lasers in the posterior segment of the eye.

Risk factors for posterior capsule rupture in cataract surgery as reflected in the European Registry of Quality Outcomes for Cataract and Refractive Surgery

PURPOSE

To analyze the incidence and risk factors for posterior capsule rupture (PCR) in cataract surgery.

SETTING

European clinics affiliated with the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO).

DESIGN

Retrospective cross-sectional register-based study.

METHODS

Data were obtained from the EUREQUO. The database contains data on demographics, comorbidities, and intraoperative complications, including PCR for the study period from January 1, 2008, to December 31, 2018. Univariate and multivariate logistic regression analyses were performed to estimate the (adjusted) odds ratio (OR) and 95% confidence intervals (CIs).

RESULTS

We analyzed EUREQUO registry data of 2,853,376 patients, and 31,749 (1.1%) cataract surgeries were complicated by a PCR. Data were available of 2 853 376 patients, and 31 749 (1.1%) cataract surgeries were complicated by a PCR. The PCR rate ranged from 0.60% to 1.65% throughout the years, with a decreasing trend (P < .001). The mean age of the PCR cohort was 74.8 ± 10.5 years, and 17 29 (55.5%) patients were female. Risk factors most significantly associated with PCR were corneal opacities (OR 3.21, 95% CI, 3.02-3.41, P < .001), diabetic retinopathy (OR 2.74, 95% CI, 2.59-2.90, P < .001), poor preoperative visual acuity (OR 1.98, 95% CI, 1.88-2.07, P < .001), and white cataract (OR 1.87, 95% CI, 1.72-2.03, P < .001).

CONCLUSIONS

Risk factors for PCR were identified based on the EUREQUO, and the incidence of this complication is decreasing over time.

Outcomes of Human Leukocyte Antigen-Matched Allogeneic Cultivated Limbal Epithelial Transplantation in Aniridia-Associated Keratopathy-A Single-Center Retrospective Analysis

PURPOSE

To assess the efficacy and safety of human leukocyte antigen-matched allogeneic cultivated limbal epithelial stem cell grafts in the treatment of aniridia-associated keratopathy (AAK).

METHODS

Six eyes of 6 patients with severe AAK received an allogeneic stem cell graft between January 2010 and March 2017. Anatomical and functional results were assessed at 6 months, 1 year, 2 years, and the final follow-up visit available. Safety analysis was performed by considering all perioperative and postoperative adverse events and additional surgeries required during the follow-up period.

RESULTS

The mean follow-up was 53.6 months (range 24-104 months). In most patients (80%), there was an early improvement of the keratopathy postoperatively, which slowly regressed during longer follow-up. At the final follow-up, 4 of the eyes were graded as failure and 1 eye was graded as partial success. Grading the sixth eye was not possible because of an adverse event. None of the patients maintained a total anatomical success in the long-term. Only 1 patient maintained a modest improvement in best-corrected visual acuity from hand motion to counting fingers. Four serious adverse events were recorded in 2 patients.

CONCLUSIONS

Severe AAK remains a challenging condition to manage. Transplantation of allogenic ex vivo cultivated limbal stem cells may provide a temporary improvement in ocular surface stability, but anatomical and functional results are poor in the long-term. The eyes are prone to adverse events, and any surgical treatment should take this into consideration.

The importance of the epithelial fibre cell interface to lens regeneration in an in vivo rat model and in a human bag-in-the-lens (BiL) sample

Human lens regeneration and the Bag-in-the-Lens (BIL) surgical treatment for cataract both depend upon lens capsule closure for their success. Our studies suggest that the first three days after surgery are critical to their long-term outcomes. Using a rat model of lens regeneration, we evidenced lens epithelial cell (LEC) proliferation increased some 50 fold in the first day before rapidly declining to rates observed in the germinative zone of the contra-lateral, un-operated lens. Cell multi-layering at the lens equator occurred on days 1 and 2, but then reorganised into two discrete layers by day 3. E- and N-cadherin expression preceded cell polarity being re-established during the first week. Aquaporin 0 (AQP0) was first detected in the elongated cells at the lens equator at day 7. Cells at the capsulotomy site, however, behaved very differently expressing the epithelial mesenchymal transition (EMT) markers fibronectin and alpha-smooth muscle actin (SMA) from day 3 onwards. The physical interaction between the apical surfaces of the anterior and posterior LECs from day 3 after surgery preceded cell elongation. In the human BIL sample fibre cell formation was confirmed by both histological and proteome analyses, but the cellular response is less ordered and variable culminating in Soemmerring's ring (SR) formation and sometimes Elschnig's pearls. This we evidence for lenses from a single patient. No bow region or recognisable epithelial-fibre cell interface (EFI) was evident and consequently the fibre cells were disorganised. We conclude that lens cells require spatial and cellular cues to initiate, sustain and produce an optically functional tissue in addition to capsule integrity and the EFI.

Adapted Bag-in-the-Lens Implantation Technique in Children with Congenital Ectopia Lentis

BACKGROUND

Subluxation of the crystalline lens in childhood confronts the surgeon with a dilemma: to operate or to wait and see. Surgery is usually not performed when the subluxation is still limited. However, postponing the surgery increases the surgical difficulty as the capsular bag becomes more difficult to use as a means of support for the intraocular lens (IOL). A large number of children already present a pronounced subluxation at first presentation. In this paper, we describe a technique to optimise centration and fixation of the bag-in-the-lens (BIL) IOL in children younger than 7 years of age with congenital ectopia lentis.

METHODS

Between October 2019 and December 2020, we performed lens extraction using a combination of bean-shaped segments to support the BIL IOL and a 6 - 0 polypropylene loop fixated at the sclera, following the Yamane technique, for the purpose of centration. We used this technique for seven eyes of four patients. The patients were between 2 and 6 years old; 3 boys and 1 girl. A definite diagnosis of Marfan syndrome was made for two children; for the other two, there was no proven underlying pathology. The luxation was upwards in all cases. The degree of luxation was severe in all eyes. The preoperative refraction values showed high astigmatism values for all eyes, ranging from 6.5 to 11.25 dioptres. Three out of the four patients were myopic, ranging from - 1.5 to - 9 dioptres.

RESULTS

The surgery could be performed without major complications in all eyes. Good centration was obtained, which remained stable in the postoperative period. Refraction improved with greatly diminished degrees of astigmatism (ranging from 0.25 to 3 dioptres) and myopia (spheres ranging from - 2 to + 1.75 dioptres).

CONCLUSION

Our novel technique incorporated the BIL technique with the addition of bean-shaped segments and a polypropylene 6/0 suture fixated at the sclera. In this way, we were able to obtain good centration and stability of the implanted IOL, as well as a good refractive outcome in all cases.

Real-time intraoperative OCT imaging of the vitreolenticular interface during pediatric cataract surgery

PURPOSE

To report on the use of intraoperative optical coherence tomography (OCT) imaging of the vitreolenticular interface (VLI) during pediatric cataract surgery and to determine the incidence of VLI dysgenesis and surgical difficulties.

SETTING

Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.

DESIGN

Retrospective cohort study.

METHODS

This study included 51 pediatric patients who underwent cataract surgery between April 2016 and December 2018. Video recordings and OCT images of the VLI were analyzed and compared. VLI dysgenesis was considered present when intraoperative OCT images demonstrated partial or total adhesions between the posterior lens capsule and the anterior hyaloid membrane. Video recordings were analyzed to describe surgical difficulties, more specifically: inability to create a calibrated primary posterior continuous curvilinear capsulorhexis (PPCCC), occurrence of vitreous prolapse, need for anterior vitrectomy, and complicated IOL implantation.

RESULTS

Of the 51 patients included, VLI dysgenesis was demonstrated in 27 patients (52.9%). The incidence of VLI dysgenesis was greater in children with unilateral cataract (72.4%), and children with a posterior capsule plaque (90%). PPCCC was challenging in 20 patients. A defect of the anterior hyaloid membrane was found in 16 patients. Anterior vitrectomy or cutting vitreous strands with scissors was necessary in 10 patients.

CONCLUSIONS

Intraoperative OCT images were an excellent tool to evaluate the VLI and to demonstrate the presence of VLI dysgenesis during pediatric cataract surgery. Performing a calibrated PPCCC was more challenging in the presence of VLI dysgenesis. This can subsequently expose a defect in the anterior hyaloid membrane, which may result in vitreous prolapse.

Intraocular Bag-in-the-Lens Exchange: Indications, Outcomes and Complications

PURPOSE

To report the indications, outcomes, and complications regarding the Bag-in-the-lens (BIL) intraocular lens (IOL) exchanges over a period of 13 years in a tertiary ophthalmologic centre.

SETTING

Department of Ophthalmology of the University Hospital of Antwerp (UZA).

DESIGN

Observational retrospective study.

PATIENTS AND METHODS

Between 2003 and 2020, 12 176 patients were operated using the BIL technique. We included adult patients who underwent an intraocular BIL exchange and recorded the demographics, indications, outcomes, and complications.

RESULTS

Fifty-nine eyes of 59 patients who underwent a BIL exchange between 2007 and 2020 were included (0.48%). The mean age was 61.15 ±13.53 years. The mean time between primary surgery and IOL exchange was 25.73 ± 41.88 months. The main indication for explantation was refractive surprise mostly related to the patients' risk factors e.g. preoperative corneal and refractive surgery. The mean preoperative uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were 0.36 ± 0.24 and 0.79 ± 0.24 respectively. The postoperative 1 month-UDVA and CDVA were 0.66 ± 0.28 and 0.86 ± 0.19 respectively. The improvement in UDVA was statistically significant (<0.0001). The most common peroperative complication was damage to the anterior hyaloid in 9 eyes (15%), which did not prohibit reimplantation of a secondary BIL.

CONCLUSIONS

BIL to BIL exchange is an viable and successful technique that provides good refractive results with few, manageable complications. Because of the tertiary profile of our centre with referral of complex cases, BIL was our preferred IOL in patients at risk of postoperative refractive surprise.

Current Knowledge about the Anterior Interface in Children Operated for Congenital Cataract

The relationship between the anterior vitreous interface and the posterior capsule has received increasing attention in the past decade. The advent of integrated intraoperative optical coherence tomography has allowed a real-time opportunity to grasp this dynamic understanding. Here we describe the normal anatomy of this interface in children and then demonstrate the variation in this interface with different forms of pediatric cataract, namely a posterior plaque and posterior capsular opacity due to abnormal adherence to the vitreous face. The authors describe these changes using meticulous annotation. An understanding of these differences will aid the surgeon in managing pediatric cataracts in a more confident and safe manner.

Risk factors for dropped nucleus in cataract surgery as reflected by the European Registry of Quality Outcomes for Cataract and Refractive Surgery

PURPOSE

To analyze the incidence, risk factors, and outcomes of cataract surgery complicated by a dropped nucleus.

SETTING

Patients who have received cataract surgery in 18 European countries.

DESIGN

Retrospective cross-sectional register-based study.

METHODS

Data from the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO) were analyzed. The EUREQUO contains preoperative baseline, intraoperative, and follow-up data. Intraoperative data include dropped nucleus as a complication. Baseline data such as demographic data, ocular comorbidities, surgical difficulties, and visual and refractive outcomes were tested for association with a dropped nucleus for the study period from January 1, 2008, to December 31, 2018.

RESULTS

The number of reported patients with complete data was 1 715 348. Dropped nucleus was reported in 1221 eyes (0.071%) during the study period. White cataract, previous vitrectomy, poor preoperative visual acuity, small pupil, pseudoexfoliation, diabetic retinopathy, and male sex were significantly related to dropped nucleus. Year of surgery showed a significant trend of decreasing occurrence of dropped nucleus over time. Eyes with the complication of a dropped nucleus also had a poorer visual and refractive outcome compared with eyes with existing risk factors but no such complication.

CONCLUSIONS

Many risk factors for dropped nucleus complications were identified. A significant trend of decreasing occurrence of dropped nucleus was found for the study period. The visual and refractive outcome was poorer for eyes with a dropped nucleus.

Clinical and Surgical Outcome of a Supplementary Multifocal Intraocular Lens Implanted with a Bag-In-the-Lens Intraocular Lens: 5-Year Follow-Up

INTRODUCTION

To assess the postoperative outcome and patient-reported satisfaction, spectacle independence, and dysphotopsia after implantation with the mutifocal Rayner Sulcoflex supplementary intraocular lens (sIOL).

MATERIALS AND METHODS

We analyzed the outcome of all patients implanted with a multifocal sIOL between 2009 and 2011. In all cases, the sIOL was the Rayner Sulcoflex IOL (type 653F) and the primary IOL was a bag-in-the-lens (BIL) IOL. The data were obtained through a retrospective analysis of the patient records and by means of a questionnaire, 5 years after sIOL implantation.

RESULTS

This study included 31 eyes of 20 patients. In 13 eyes, the sIOL needed explantation (n = 13, 41.94%). Dysphotopsia is a frequent complaint (12/15 patients: 80.0%) after sIOL implantation. In 13 out of 31 eyes (41.94%), pigment deposits were found on the sIOL with variable clinical complaints. Five eyes required additional surgery because of clinically significant deposits.

DISCUSSION/CONCLUSION

Patients with a multifocal sIOL in combination with a BIL implantation have a higher incidence of dysphotopsia compared to previously published studies. Dysphotopsia was the main complaint and reason for explantation. We encountered a high incidence of pigmented IOL deposits. The sIOLs can be safely removed even years after implantation.

Safety and efficacy of a standardized intracameral combination of mydriatics and anesthetic for cataract surgery in type-2 diabetic patients

Background

Cataract surgery in diabetics is more technically challenging due to a number of factors including poor intraoperative pupil dilation and a higher risk of vision threatening complications. This study evaluates the safety and efficacy of an intracameral combination of 2 mydriatics and 1 anesthetic (ICMA, Mydrane) for cataract surgery in patients with well-controlled type-2 diabetes.

Methods

Post-hoc subgroup analysis of a phase 3 randomized study, comparing ICMA to a conventional topical regimen. Data were collected from 68 centers in Europe and Algeria. Only well-controlled type-2 diabetics, free of pre-proliferative retinopathy, were included. The results for non-diabetics are also reported. The primary efficacy variable was successful capsulorhexis without additional mydriatic treatment. Postoperative safety included adverse events, endothelial cell density and vision.

Results

Among 591 randomized patients, 57 (9.6%) had controlled type 2 diabetes [24 (42.1%) in the ICMA Group and 33 (57.9%) in the Topical Group; intention-to-treat (ITT) set]. Among diabetics, capsulorhexis was successfully performed without additional mydriatics in 24 (96.0%; modified-ITT set) patients in the ICMA Group and 26 (89.7%) in the Topical Group. These proportions were similar in non-diabetics. No diabetic patient [1 (0.5%) non-diabetics] in the ICMA Group had a significant decrease in pupil size (≥3 mm) intraoperatively compared to 4 (16.0%; modified-ITT set) diabetics [16 (7.3%) non-diabetics] in the Topical group. Ocular AE among diabetics occurred in 2 (8.0%; Safety set) patients in the ICMA Group and 5 (16.7%) in the Topical Group. Endothelial cell density at 1 month postoperatively was similar between groups in diabetics (P = 0.627) and non-diabetics (P = 0.368).

Conclusions

ICMA is effective and can be safely used in patients with well-controlled diabetes, with potential advantages compared to a topical regimen including reduced systemic risk, better corneal integrity and reduced risk of ocular complications.

Trial registration

The trial was registered at (reference # NCT02101359) on April 2, 2014.

Photoablation of Human Vitreous Opacities by Light-Induced Vapor Nanobubbles

Myopia, diabetes, and aging are the main causes of progressive vitreous collagen aggregation, resulting in vitreous opacities, which can significantly disturb vision. As vitreous opacities, which induce the visual phenomenon of "floaters", are accessible with nanomaterials and light, we propose a nanotechnology-based approach to locally ablate them with highly reduced light energy compared to the more traditional YAG laser therapy. Our strategy relies on the plasmon properties of gold nanoparticles that generate vapor nanobubbles upon pulsed-laser illumination whose mechanical force can ablate vitreous opacities. We designed gold nanoparticles coated with hyaluronic acid (HA), which have excellent diffusional mobility in human vitreous, an essential requirement to reach the vitreous opacities. In addition, we found that HA-coated gold nanoparticles can accumulate extensively on human vitreous opacities that were obtained by vitrectomy from patients with vision-degrading myodesopsia. When subsequently applying nanosecond laser pulses, the collagen aggregates were efficiently destroyed with ∼1000 times less light energy than typically used in YAG laser therapy. This low-energy "floater-specific destruction", which is due to the accumulation of the small gold nanoparticles on the opacities, is attractive, as it may be safer to the surrounding ocular tissues while at the same time being easier and faster to apply compared to YAG laser therapy, where the opacities need to be ablated piece by piece by a tightly focused laser beam. Gold nanoparticle-assisted photoablation may therefore provide a safer, faster, and more reliable destruction of vitreous opacities in the treatment of ophthalmologic diseases.

Proteomic analysis of posterior capsular plaques in congenital unilateral cataract

PURPOSE

To obtain insights on the protein composition of posterior capsular plaques (PCP) in congenital unilateral cataract with anterior vitreolenticular interface dysgenesis (AVLID).

METHODS

Posterior capsular plaque's were collected during surgery in children presenting with congenital unilateral cataract. Surgeries were analysed focusing on the type of cataract, the integrity of the posterior capsule after peeling the PCP and the presence of vitreolenticular adherences when performing primary posterior capsulorhexis. Proteome analysis was performed on the collected PCPs.

RESULTS

Posterior capsular plaques collection and proteome analysis were feasible from four children presenting with unilateral idiopathic congenital cataract and AVLID. A large portion of the proteins found in the PCPs was similar to the proteins known to be present in lens epithelial cells and fibres. Proteins like vimentin, fibronectin, collagen type I, collagen type VI and lumican were also found, which typically are present in mesenchymal tissue but not in lens tissue or capsule.

CONCLUSION

Posterior capsular plaques in cases of unilateral idiopathic congenital cataract of the AVLID type present a protein composition of mainly proteins found in lens epithelial cells and fibres. Some proteins however are a specific for lens tissue and are typically seen in mesenchymal tissue.

Immunohistochemical characteristics of the vitreolenticular interface in congenital unilateral posterior cataract

PURPOSE

To gain insight into the histology of the vitreolenticular interface in congenital unilateral posterior cataract.

SETTING

Antwerp University Hospital, Department of Ophthalmology, Edegem, and the University of Antwerp, Faculty of Medicine and Health Sciences, Antwerp, Belgium.

DESIGN

Prospective case study.

METHODS

Samples of the posterior lens capsule of patients with congenital posterior cataract (including opaque plaque on the anterior and adhesion to the vitreous on the posterior surface) were collected during the posterior capsulorhexis procedure. Staining for collagen types II and IV was performed using indirect immunohistochemistry. Results were compared with those of control posterior lens capsules of 3 children and 3 adults.

RESULTS

Samples were collected from 3 patients. All posterior lens capsules contained collagen type IV. Samples from congenital posterior cataract patients all showed a narrow band of collagen type II on the outer surface, indicating strong adherence of the anterior hyaloid membrane to the center of the posterior lens capsule. Surprisingly, collagen type II was also found in the posterior capsule plaques. Collagen type II was not found in any control posterior lens capsule.

CONCLUSION

The adherence of collagen type II to the center of the posterior lens capsule histologically supports the hypothesis that this subgroup of congenital cataract hints at an abnormality at the vitreolenticular interface.

FINANCIAL DISCLOSURE

None of the authors has a financial or proprietary interest in any material or method mentioned.

Influence of the vitreolenticular interface in pediatric cataract surgery

PURPOSE

To report the status of Berger space in pediatric cataract cases and the influence of anterior vitreolenticular interface dysgenesis during primary posterior continuous curvilinear capsulorhexis (PCCC).

SETTING

Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.

DESIGN

Prospective case series.

METHODS

The study comprised consecutive pediatric cataract cases planned for bag-in-the-lens intraocular lens (BIL IOL) implantation. A video-based analysis of the surgical interventions included the type of crystalline lens opacification, presence of a posterior capsule plaque (PCP), presence of anterior vitreolenticular interface dysgenesis, complications during primary PCCC, integrity of the anterior hyaloid membrane, need for anterior vitrectomy, and feasibility of BIL IOL implantation.

RESULTS

Abnormalities in Berger space were observed in 35 of the 64 pediatric cataract cases. Anterior vitreolenticular interface dysgenesis was most often found in cases with persistent fetal vasculature (PFV) and those with posterior cataract. Anterior vitreolenticular interface dysgenesis was diagnosed significantly more often in eyes with unilateral cataract and those with PCP. In pediatric cataract cases presenting with PCP and anterior vitreolenticular interface dysgenesis, the primary PCCC procedure was surgically more demanding, often resulting in detectable breaks in the anterior hyaloid membrane (58.6%) and sometimes necessitating an unplanned anterior vitrectomy (13.8%). Bag-in-the-lens IOL implantation was feasible in all except 1 eye with PFV, which was left aphakic.

CONCLUSIONS

Primary vitreolenticular interface abnormalities are often encountered during pediatric cataract surgeries, especially when confronted with PCP in a unilateral cataract. The presence of anterior vitreolenticular interface dysgenesis may complicate a primary PCCC procedure, resulting in an unplanned anterior vitrectomy in some cases.

Indications for Q-Switched and Mode-Locked Nd: Yag Lasers in Vitreoretinal Pathology

The indications for two types of pulsed Nd: YAG lasers in the treatment of vitreous pathology are reviewed. A series of 94 eyes from 93 patients were treated with the mode-locked system and 72 eyes from 71 patients were treated with the Q-switched system. A classification of vitreous pathology with prognostic value for the efficacy of treatment of both lasers is established. For the Q-switched laser the range of indications in the posterior pole is larger and fewer sessions are needed; however, complications are more frequent than with the mode-locked laser. This difference is due to the higher energy needed with the Q-switched laser to treat more severe vitreous pathology.

Modified bean-shaped ring segments for suture fixation of the bag-in-the-lens intraocular implant

We describe a surgical technique for secondary stabilization of a bag-in-the-lens intraocular lens (BIL IOL) using 2 modified bean-shaped ring segments in cases of zonular dehiscence associated with pseudophakodonesis. The first modified bean segment is anchored in the sulcus with a suture to the sclera in the area of maximum zonular dehiscence, and the second segment is implanted in the opposite sulcus area. Both segments are placed in the BIL IOL interhaptic groove. The segments stabilize and center the BIL IOL by creating an artificial zonule that provides the necessary extra support for the IOL.

A review of the evidence for in vivo corneal endothelial regeneration

Human corneal endothelium has long been thought to be a nonmitotic cell layer with no endogenous reparative potential. Pathologies that damage endothelial function result in corneal decompensation and, if untreated, blindness. The mainstay of treatment involves partial or complete corneal replacement, amounting to 40% of all corneal transplants performed worldwide. We summarize the case reports describing complications postoperatively in the form of (sub)total graft detachment and those resulting in postoperative bare stroma. Complications during cataract and glaucoma surgeries leading to an uncovered posterior cornea are also included. We discuss the newer treatment strategies that are alternatives for current Descemet membrane endothelial keratoplasty and Descemet stripping automated endothelial keratoplasty, including partial grafts and stripping of the diseased cell layer. In more than half of the cases reviewed, corneal transparency returned despite incomplete or no corneal endothelial cell transplantation. We question the existing paradigm concerning corneal endothelial wound healing in vivo. The data support further clinical study to determine the safety of simple descemethorexis in central endothelial pathologies, such as Fuchs endothelial corneal dystrophy, where presence of healthy peripheral cells may allow successful corneal recompensation without the need for donor cells.

Influence of yellow filters on straylight measurements

PURPOSE

To determine whether the yellow filters often used for glare reduction influence retinal straylight measured in healthy eyes.

SETTING

Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.

DESIGN

Prospective case series.

METHODS

For each eye, the spherical equivalent (SE) was determined using an autorefractometer, followed by 5 straylight measurements taken with the compensation-comparison method. The first measurement was taken with a colorless plano lens placed in front of the eye, followed by 4 other measurements with yellow filters with cutoff wavelengths at 450 nm, 511 nm, 527 nm, and 550 nm. Ametropic volunteers were corrected using an additional lens in all measurements. Age, sex, and eye color were listed. In addition to the basic measurements, base- and age-corrected and base-, age-, and SE-corrected values were calculated.

RESULTS

The data from 56 right eyes of 56 healthy volunteers aged 28.7 years ± 10.3 (SD) were assessed. The straylight of the 4 yellow filters was significantly higher than that of the plano lens (P < .001, analysis of variance [ANOVA]). The straylight also increased with higher cutoff frequencies, albeit insignificantly (P > .05, ANOVA). No significant difference was found between sexes (P = .909) or between eye colors (P > .05).

CONCLUSIONS

The use of yellow filters increased retinal straylight by a small but significant amount compared with the use of unfiltered light. This suggests that the visual comfort often experienced while wearing these filters is not associated with reduced straylight.

SyntEyes KTC: higher order statistical eye model for developing keratoconus

PURPOSE

To present and validate a stochastic eye model for developing keratoconus to e.g. improve optical corrective strategies. This could be particularly useful for researchers that do not have access to original keratoconic data.

METHODS

The Scheimpflug tomography, ocular biometry and wavefront of 145 keratoconic right eyes were collected. These data were processed using principal component analysis for parameter reduction, followed by a multivariate Gaussian fit that produces a stochastic model for keratoconus (SyntEyes KTC). The output of this model is filtered to remove the occasional incorrect topography patterns by either an automatic or manual procedure. Finally, the output of this keratoconus model is matched to that of the original model for normal eyes using the non-corneal biometry to obtain a description of keratoconus development.

RESULTS

The synthetic data generated by the model were found to be significantly equal to the original data (non-parametric Mann-Whitney equivalence test; 145/154 passed). The variability of the synthetic data, however, was often significantly less than that of the original data, especially for the higher order Zernike terms of corneal elevation (non-parametric Levene test; p < 0.05/154). These results remained generally the same after applying either filter procedure to remove the synthetic eyes with incorrect topographies. Interpolation between matched pairs of normal and keratoconic SyntEyes appears to provide an adequate model for keratoconus progression.

CONCLUSION

The synthetic data provided by the proposed keratoconus model closely resembles actual clinical data and may be used for a range of research applications when (sufficient) real data is not available.

A method for quantifying limbal stem cell niches using OCT imaging

Aims

To evaluate the efficacy of Fourier domain-optical coherence tomography (FD-OCT) in imaging and quantifying the limbal palisades of Vogt and to correlate these images with histological findings.

Methods

The superior and inferior limbal region of both eyes of 50 healthy volunteers were imaged by FD-OCT. Images were processed and analysed using Matlab software. In vitro immunofluorescent staining of a cadaveric donor limbus was analysed to correlate the presence of stem cells in the visualised structures.

Results

FD-OCT could successfully visualise limbal crypts and the palisades of Vogt in the limbus region. Fluorescent labelling confirmed the presence of stem cells in these structures. The mean palisade ridge width (Δ_PR) and the mean interpalisade epithelial rete peg width (Δ_ERP) were both of the order of 72 μm, leading to a palisade density (PD) of about 7.4 palisades/mm. A significant difference in Δ_PR, Δ_ERP and PD was seen between the inferior and superior sides of the right eye and the superior sides of the left and right eye(p<0.05.). A significant influence of iris colour on parameters Δ_PR, Δ_ERP and PD was found, and of age on PD and Δ_ERP (p<0.05).

Conclusions

In vivo OCT imaging is a safe and effective modality to image the limbus and can be used to visualise the palisades of Vogt. Image processing using Matlab software enabled quantification and density calculation of imaged limbal palisades of Vogt. This technique may enhance targeted limbal biopsies for transplantation.

Procedural aspects of the organization of the comprehensive European Board of Ophthalmology Diploma examination

The comprehensive European Board of Ophthalmology Diploma (EBOD) examination is one of 38 European medical specialty examinations. This review aims at disclosing the specific procedures and content of the EBOD examination. It is a descriptive study summarizing the present organization of the EBOD examination. It is the 3rd largest European postgraduate medical assessment after anaesthesiology and cardiology. The master language is English for the Part 1 written test (knowledge test with 52 modified type X multiple-choice questions) (in the past the written test was also available in French and German). Ophthalmology training of minimum 4 years in a full or associated European Union of Medical Specialists (UEMS) member state is a prerequisite. Problem-solving skills are tested in the Part 2 oral assessment, which is a viva of 4 subjects conducted in English with support for native language whenever feasible. The comprehensive EBOD examination is one of the leading examinations organized by UEMS European Boards or Specialist Sections from the point of number of examinees, item banking, and item contents.

Real-Time Intraoperative Optical Coherence Tomography Imaging Confirms Older Concepts About the Berger Space

BACKGROUND

The presence of a space between the posterior capsule and the anterior vitreous was first reported in 1887, but difficulties inherent in examining this structure made it impossible to visualize this area in vivo until now. Estimation of the size of this space was considered to be impossible.

MATERIALS AND METHODS

We utilized an optical coherence tomography (OCT) system attached to the Zeiss Opmi Lumera 700/Rescan microscope (Zeiss Ltd., Jena, Germany) to provide real-time images of the Berger space, the anterior hyaloid and the ligament of Wieger.

RESULTS

Imaging in 3 patients provided beautiful, real-time OCT images of the Berger space and of the ligament of Wieger. In one highly myopic eye, there was even evidence of anterior vitreous detachment.

CONCLUSION

Previously unseen transparent structures of the eye can now be imaged intraoperatively using real-time OCT. This new technology seems very promising in achieving a better understanding of the anterior vitreous interface, more specifically of the anterior hyaloid and its posterior capsule attachment by the ligament of Wieger. Changes in the anterior hyaloid and its capsular attachment may contribute to a better understanding of the posterior segment complications after cataract surgery.

Subjective Grading of Subclinical Vitreous Floaters

PURPOSE

This study aimed to objectively grade the perception of subclinical floaters in an asymptomatic cohort.

DESIGN

A prospective observational cohort study.

METHODS

One hundred eighty-two volunteers (49 men, 133 women) with ages ranging from 17.7 to 78.6 years were recruited for floater assessment. Participants were assessed by a light box and by vitreoscope, after which they graded the floaters using a graphic classification system. They also completed a questionnaire to estimate the impact of floaters on daily life. In addition, biometric and refractive data were documented for all participants.

RESULTS

Using the light box method, 67.6% of participants reported seeing transparent floaters, which increased to 84.1% when using the vitreoscope. Opaque floaters were seen by 15.9% (light box) and 6.5% (vitreoscope). Reported levels of floater discomfort varied between participants, with 80.2% of participants reporting no discomfort and 6.6% reporting moderate to manifest discomfort. The perceived discomfort was weakly correlated with the amount of visualized floaters (light box: Pearson r = 0.323, P < 0.001; vitreoscope: r = 0.174, P < 0.001). Both floater perception and discomfort increased with age (r = 0.203, P = 0.006; r = 0.194, P = 0.009, respectively), although neither changed with axial length or refraction (P = 0.131, P = 0.070, respectively).

CONCLUSIONS

The light box and the vitreoscope demonstrate that subclinical floaters are very common, even in nonsymptomatic subjects. The amount of perceived floaters in this cohort correlates only weakly with floater-related discomfort.

SyntEyes: A Higher-Order Statistical Eye Model for Healthy Eyes

PURPOSE

Stochastic eye models are a method to generate random biometry data with the variability found in the general population for use in optical calculations. This work improves the accuracy of a previous model by including the higher-order shape parameters of the cornea.

METHODS

The right eye biometry of 312 subjects (40.8 ± 11.0 years of age) were measured with an autorefractometer, a Scheimpflug camera, an optical biometer, and a ray tracing aberrometer. The corneal shape parameters, exported as Zernike coefficients, were converted to eigenvectors for dimensional reduction. The remaining 18 parameters were modeled as a sum of two multivariate Gaussians, from which an unlimited number of synthetic data sets (SyntEyes) were generated. After conversion back to Zernike coefficients, the data were introduced into ray tracing software.

RESULTS

The mean values of nearly all SyntEyes parameters were statistically equal to those of the original data (two one-sided t-test, P > 0.05/109, Bonferroni correction). The variability of the SyntEyes parameters was similar to the original data for most important shape parameters and intraocular distances (F-test, P < 0.05/109), but significantly lower for the higher-order shape parameters (F-test, P > 0.05/109). The same was seen for the correlations between higher-order shape parameters. After applying simulated cataract or refractive surgery to the SyntEyes model, a very close resemblance to previously published clinical outcome data was seen.

CONCLUSIONS

The SyntEyes model produces synthetic biometry that closely resembles clinically measured data, including the normal biological variations in the general population.

Incidence of rhegmatogenous retinal detachment after bag-in-the-lens intraocular lens implantation

PURPOSE

To determine the incidence of rhegmatogenous retinal detachment (RRD) and associated risk factors after phacoemulsification and bag-in-the-lens intraocular lens (IOL) implantation.

SETTING

Antwerp University Hospital, Department of Ophthalmology, Antwerp, Belgium.

DESIGN

Prospective cohort study.

METHODS

All consecutive bag-in-the-lens IOL implantations performed between January 2001 and December 2007 were included, with the exception of combined procedures and IOL exchanges. The retinal detachment (RD) incidence was studied in the total cohort, in a subgroup of patients with 1 to 5 years of follow-up, and finally in the group remaining after exclusion of all risk factors except gender.

RESULTS

RD after bag-in-the-lens IOL implantation in 1323 eyes with an average follow-up of 44.75 months (range 0 to 152 months) was found in 19 eyes (1.44%). The 1-year RD incidence was 0.49% (5 RD cases in 1024 eyes) (0.00% in patients without risk factors). The 2-year cumulative RD incidence was 0.84% (9 RD cases in 931 eyes; 0.15% without risk factors). Four clinically significant risk factors were confirmed: male gender, young age at time of surgery (<60 years), axial myopia (axial length ≥25 mm), and history of contralateral RD in the total cohort.

CONCLUSION

The RRD incidence following bag-in-the-lens IOL implantation was comparable to that seen after lens-in-the-bag (LIB) implantation. The wide variation in study design in the literature precludes direct comparison, so there is a need for standardization in evaluating RRD incidence after cataract surgery. Future prospective studies should consider patients with and without risk factors (except gender) separately.

FINANCIAL DISCLOSURE

Prof. dr. M.J. Tassignon has intellectual property rights to the bag-in-the-lens intraocular lens (U.S. patent 6 027 531; EU patent 009406794; PCT/120268), which is licensed to Morcher GmbH, Stuttgart, Germany.

Biocompatibility of a fish scale-derived artificial cornea: Cytotoxicity, cellular adhesion and phenotype, and in vivo immunogenicity

PURPOSE

To determine whether a fish scale-derived collagen matrix (FSCM) meets the basic criteria to serve as an artificial cornea, as determined with in vitro and in vivo tests.

METHODS

Primary corneal epithelial and stromal cells were obtained from human donor corneas and used to examine the (in)direct cytotoxicity effects of the scaffold. Cytotoxicity was assessed by an MTT assay, while cellular proliferation, corneal cell phenotype and adhesion markers were assessed using an EdU-assay and immunofluorescence. For in vivo-testing, FSCMs were implanted subcutaneously in rats. Ologen(®) Collagen Matrices were used as controls. A second implant was implanted as an immunological challenge. The FSCM was implanted in a corneal pocket of seven New Zealand White rabbits, and compared to sham surgery.

RESULTS

The FSCM was used as a scaffold to grow corneal epithelial and stromal cells, and displayed no cytotoxicity to these cells. Corneal epithelial cells displayed their normal phenotypical markers (CK3/12 and E-cadherin), as well as cell-matrix adhesion molecules: integrin-α6 and β4, laminin 332, and hemi-desmosomes. Corneal stromal cells similarly expressed adhesion molecules (integrin-α6 and β1). A subcutaneous implant of the FSCM in rats did not induce inflammation or sensitization; the response was comparable to the response against the Ologen(®) Collagen Matrix. Implantation of the FSCM in a corneal stromal pocket in rabbits led to a transparent cornea, healthy epithelium, and, on histology, hardly any infiltrating immune cells.

CONCLUSION

The FSCM allows excellent cell growth, is not immunogenic and is well-tolerated in the cornea, and thus meets the basic criteria to serve as a scaffold to reconstitute the cornea.

Evaluation of the efficacy and safety of a standardised intracameral combination of mydriatics and anaesthetics for cataract surgery

Background/aims

To compare the efficacy and safety of intracameral (IC) administration at the beginning of cataract surgery, of Mydrane, a standardised ophthalmic combination of tropicamide 0.02%, phenylephrine 0.31% and lidocaine 1%, to a standard topical regimen.

Methods

In this international phase III, prospective, randomised study, the selected eye of 555 patients undergoing phacoemulsification with intraocular lens (IOL) implantation received 200 μL of Mydrane (Mydrane group) just after the first incision or a topical regimen of one drop each of tropicamide 0.5% and phenylephrine 10% repeated three times (reference group). The primary efficacy variable was achievement of capsulorhexis without additional mydriatics. The non-inferiority of Mydrane to the topical regimen was tested. The main outcome measures were pupil size, patient perception of ocular discomfort and safety.

Results

Capsulorhexis without additional mydriatics was performed in 98.9% of patients and 94.7% in the Mydrane and reference groups, respectively. Both groups achieved adequate mydriasis (>7 mm) during capsulorhexis, phacoemulsification and IOL insertion. IOL insertion was classified as ‘routine’ in a statistically greater number of eyes in the Mydrane group compared with the reference group (p=0.047). Patients in the Mydrane group reported statistically greater comfort than the reference group before IOL insertion (p=0.034). Safety data were similar between groups.

Conclusions

Mydrane is an effective and safe alternative to standard eye drops for initiating and maintaining intraoperative mydriasis and analgesia. Patients who received IC Mydrane were significantly more comfortable before IOL insertion than the reference group. Surgeons found IOL insertion less technically challenging with IC Mydrane.

Trial registration number

NCT02101359; Results.

Optical Coherence Tomography in Cultivated Limbal Epithelial Stem Cell Transplantation Surgery

PURPOSE

Cultivated limbal epithelial stem cell transplantation (CLET) is a surgical approach reserved for severe stem cell deficiency and anterior segment pathology. The recipient cornea typically displays a highly vascularized pannus that must be dissected before graft placement. Extensive pannus dissection, however, can result in corneal thinning and increase the risk of ectasia and ultimately, of perforation. We aimed to examine the value of anterior segment optical coherence tomography (AS-OCT) intraoperatively during pannus resection and long-term postoperative follow-up of CLET surgery.

DESIGN

This was a prospective observational case series.

METHODS

This study was performed on 8 eyes of 8 patients who underwent CLET surgery. Intraoperative OCT was performed before dissection and at several time points during dissection and after placement of the ex vivo cultivated graft. During the postoperative follow-up period, OCT was performed to image the graft integration and corneal thickness.

RESULTS

Anterior segment optical coherence tomography provided high-resolution images of the corneal pannus, including the blood vessel lumen. Imaging of the pannus depth and cleavage plane was possible intraoperatively, with the patient supine. Postoperative imaging displayed the transplanted graft, temporary amniotic membrane patch, and overlying bandage contact lens. The grafts were also visible after removal of the temporary membrane patch. Four months postoperatively, the grafts were integrated into the cornea, and all 8 participants showed the presence of an epithelial layer.

CONCLUSIONS

During CLET surgery, AS-OCT offers a noncontact method for rapid, intraoperative scanning and pachymetry mapping. Intraoperative OCT guidance assists in the removal of the delicate fibrovascular pannus. Sparing the viable corneal stroma can reduce the risk of extreme thinning, iatrogenic ectasia, and wound dehiscence while providing a smooth recipient surface for the composite graft.

Cataract

Cataract is the leading cause of reversible blindness and visual impairment globally. Blindness from cataract is more common in populations with low socioeconomic status and in developing countries than in developed countries. The only treatment for cataract is surgery. Phacoemulsification is the gold standard for cataract surgery in the developed world, whereas manual small incision cataract surgery is used frequently in developing countries. In general, the outcomes of surgery are good and complications, such as endophthalmitis, often can be prevented or have good ouctomes if properly managed. Femtosecond laser-assisted cataract surgery, an advanced technology, can automate several steps; initial data show no superiority of this approach over current techniques, but the results of many large clinical trials are pending. The greatest challenge remains the growing 'backlog' of patients with cataract blindness in the developing world because of lack of access to affordable surgery. Efforts aimed at training additional cataract surgeons in these countries do not keep pace with the increasing demand associated with ageing population demographics. In the absence of strategie that can prevent or delay cataract formation, it is important to focus efforts and resources on developing models for efficient delivery of cataract surgical services in underserved regions. For an illustrated summary of this Primer, visit: http://go.nature.com/eQkKll.

Repeatability and inter-device agreement for three different methods of keratometry: Placido, Scheimpflug, and color LED corneal topography

PURPOSE

To determine the repeatability of a color LED corneal topographer (Cassini; iOptics, The Hague, The Netherlands) and compare it with Placido and Scheimpflug based devices (EyeSys 2000; EyeSys Laboratories, Houston, TX, and Pentacam HR; Oculus Optikgeräte GmbH, Wetzlar, Germany).

METHODS

This prospective study involved 20 healthy volunteers (20 eyes) recruited from the staff of the Antwerp University Hospital. For each eye, three measurements were taken using each device, from which eight parameters describing keratometry and astigmatism were derived. Repeatability was assessed using intrasession, within-subject analysis of variance. Agreement was evaluated between pairs of devices with Bland- Altman plots and 95% confidence intervals.

RESULTS

The repeatability values were good for all three devices, although slightly worse for the Cassini than for the other two devices for steep, flat, and mean keratometry. The EyeSys showed worse repeatability for the astigmatism axis. EyeSys and Pentacam agreed well with each other in terms of mean keratometry, whereas the Cassini gave consistently higher values by 0.52 diopters (D) when compared with the EyeSys (P < .05, paired t test) and by 0.38 D when compared with the Pentacam (P < .05, paired t test). The Cassini provided similar repeatability values (2.31°) for the astigmatism axis to the Pentacam (2.22°), in contrast to the EyeSys, which produced much more variable axes (9.0°) (P < .05, paired t test).

CONCLUSIONS

Overall, the three devices display comparable repeatability. The one exception is the astigmatism axis measurement of the EyeSys. The Cassini provides higher keratometry values than the other two devices, but the astigmatism axis agrees well with that provided by the Pentacam.

Iris atrophy and erosion caused by an anterior-chamber angle-supported phakic intraocular lens

We report a case in which an angle-supported phakic IOL was implanted to correct high myopia. Subsequently, the patient experienced photophobia, glare, halo, and loss of visual acuity and became concerned about the cosmetically deforming aspect of her eye. Findings included endothelial cell loss, cataract, pupil ovalization, and severe iris atrophy. The pIOL was removed and cataract surgery was performed, followed by implantation of a bag-in-the-lens IOL, but successful surgical repair of the iris was not possible because of severe iris atrophy.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.