[2.6 million cataract surgeries: 31 years with the Swedish National Cataract Register 1992-2022]. / 2,6 miljoner kataraktoperationer.

This review summarizes data collected by the Swedish National Cataract Register (NCR), which by the end of 2022 contained data on more than 2.6 million cataract surgeries between 1992-2022. During these 31 years, the cataract surgery rate (CSR) rose from 3 700 to 14 407. The coverage of NCR is very high, including 93% of all cataract procedures in Sweden during the last decade. A clear trend is that the procedure is performed in eyes with increasingly high visual acuity. The proportion of patients with Snellen 0.5 or worse in the first eye at surgery has decreased from 88% in 2007 to 69% in 2022. Patient Reported Outcome Measures (PROM) have been registered with the Catquest-9SF questionnaire since 2008, demonstrating stable favorable outcomes. Surgical complications have decreased; endophthalmitis has decreased from 0.10% to below 0.02%, and posterior capsule rupture from 2.8% to 0.6%.

Two point four million cataract surgeries: 30 years with the Swedish National Cataract Register, 1992-2021.

The present review summarizes data collected by the Swedish National Cataract Register (NCR), which by the end of 2021 contained data for more than 2.4 million cataract surgeries between 1992 and 2021. During these 30 years, the cataract surgery rate rose from 3700 to 12 800. The coverage of NCR is very high including 93% of all cataract procedures in Sweden between 2010 and 2021. Independently of demographic changes, the proportion of operations of patients age 60 to 79 has increased while the proportion of 80 to 90+ has decreased. The median visual acuity of the first eye planned for surgery was 0.1 decimal in 1992 and has increased to 0.5 decimal in 2021. Patient-reported outcome measures have been registered with the Catquest-9SF questionnaire since 2008, demonstrating intervention at an earlier stage, but consistently favorable outcomes. Surgical complications have decreased; endophthalmitis has decreased from 0.10% to below 0.02%, and posterior capsule rupture from 2.8% to 0.6%.

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.

Current clinical practice in corneal crosslinking for treatment of progressive keratoconus in four Nordic countries.

PURPOSE: To evaluate clinical practice in the diagnosis and treatment of progressive keratoconus with corneal crosslinking (CXL) in four Nordic countries. METHODS: A questionnaire was sent to all centres at which keratoconus patients are evaluated and CXL is performed in Sweden, Denmark, Norway and Iceland. Nineteen of 20 centres participated. RESULTS: CXL is performed approximately 1300 times per year in these four Nordic countries with a population of around 21.7 million (2019). In most cases, progression is evaluated using the Pentacam HR, and the maximum keratometry reading (Kmax ) is considered the most important parameter. The most frequently used treatment protocol in Scandinavia is the 9 mW/cm2 epi-off protocol, using hydroxylpropyl methylcellulose riboflavin (HPMC-riboflavin). The participants deemed the following areas to be in most need of improvement: adaptation of the CXL protocol to individual patients (5/19), the development of effective epi-on treatment protocols (4/19), optimal performance of CXL in thin corneas (4/19), improvement of the definition of progression (2/19), and diagnosis of the need for re-treatment (2/19). CONCLUSIONS: We concluded that the diagnosis of progressive keratoconus and the diagnostic equipment used are similar. Treatment strategies are also similar but are suitably different to provide an interesting basis for the comparison of treatment outcomes. The high degree of participation in this survey indicates the possibility of future scientific collaboration on CXL focusing on the areas deemed to need improvement. It would also be of interest to evaluate the possibility of creating a Nordic CXL Registry. The high number of CXL treatments performed ensures sufficient statistical power to solve many questions. Such a registry could be an important contribution to evidence-based care and would allow for longitudinal evaluation.

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.

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.

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.

Changing practice patterns in European cataract surgery as reflected in the European Registry of Quality Outcomes for Cataract and Refractive Surgery 2008 to 2017.

PURPOSE: To study practice patterns in European cataract surgery over a 10-year period. SETTING: European clinics affiliated to the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO). DESIGN: Registry cohort study. METHODS: The EUREQUO contains preoperative, intraoperative, and postoperative parameters reported by surgeons in many European clinics. All data reported to the registry are anonymized. Preoperative parameters included age, sex, visual acuity, target refraction, ocular comorbidity, and surgical difficulties. Surgical data included anesthesia, surgical technique, intraocular lens optic biomaterial, and complications. Postoperative parameters included visual acuity, refraction, and short-term complications. RESULTS: During the study period (January 1, 2008, to December 31, 2017), a total of 2 714 108 cataract extractions were reported to the EUREQUO. Preoperative data changed over time, with decreases in mean age (74.5-73.0 years), proportion of women from 60.6% (100 373/165 628) to 57.2% (174 908/305 845), and proportion of coexisting eye diseases from 30.0% (49 638/165 650) to 27.0% (82 704/305 846) and with improvements in preoperative visual acuity (mean logarithm of minimum angle of resolution [logMAR] 0.46 to 0.37). The use of topical anesthesia increased over time from 28.1% (26 238/93 320) to 71.7% (130 525/182 083). Surgical complications showed a significant decrease from 2.5% (4107/165 650) to 1.2% (3573/305 846). The visual outcome improved over time (mean logMAR 0.08 to 0.05), as did the absolute median prediction error (0.38 diopter [D] to 0.28 D). CONCLUSIONS: Trends in European cataract surgery practice patterns from 2008 to 2017 have moved toward younger patients with better preoperative visual acuity, fewer surgical complications, and better predicted refractions and visual outcomes.

Cataract surgery of eyes with previous vitrectomy: risks and benefits as reflected in the European Registry of Quality Outcomes for Cataract and Refractive Surgery.

PURPOSE: To explore the frequency and outcomes of cataract surgery in eyes with previous vitrectomy. SETTING: Fifteen European countries. DESIGN: Retrospective cross-sectional register-based study. METHODS: The European Registry of Quality Outcomes of Cataract and Refractive Surgery (EUREQUO) contains data on baseline characteristics, surgery, and follow-up for cataract surgeries. Previous vitrectomy is included as a mandatory parameter in baseline characteristics. According to the protocol for EUREQUO, consecutive cases should be reported by participating units. RESULTS: This study included data from units in 15 European countries from 2008 to 2018; 1 715 348 cataract extractions with follow-up data were reported to EUREQUO. Previous vitrectomy was reported in 19 416 eyes comprising 1.1% of all cases. This proportion was about the same for each study year. Most patients were men, and their mean age was 64.1 years compared with 73.7 years for the rest of the database. The preoperative visual acuity was modestly worse in postvitrectomy eyes compared with the opposite (corrected distance visual acuity [CDVA] 0.45 vs 0.25, respectively). A postoperative CDVA of 0.5 or better was achieved by 82.8% of the postvitrectomy eyes compared with 95.6% for the non-postvitrectomy eyes. The absolute mean biometry prediction error for the same groups was 0.52 diopters (D) vs 0.43 D, respectively. CONCLUSIONS: Patients undergoing cataract extraction after previous vitrectomy were younger and mostly men. Their visual and refractive outcomes were slightly inferior compared with the patients without vitrectomy.

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.

Aniridia-related keratopathy: Structural changes in naïve and transplanted corneal buttons.

BACKGROUND: To study structural changes in naïve and surgically treated corneas of aniridia patients with advanced aniridia-related keratopathy (ARK). METHODS AND FINDINGS: Two naïve corneal buttons from patients with advanced ARK submitted to penetrating keratoplasty for the first time, one corneal button from an ARK patient that had undergone a keratolimbal allograft (KLAL), two corneal buttons from ARK patients who had previously undergone centered or decentered transplantation and were now retransplanted and two adult healthy donor control corneas were processed for immunohistochemistry. Antibodies against extracellular matrix components in the stroma and in the epithelial basement membrane (collagen I and IV, collagen receptor α11 integrin and laminin α3 chain), markers of fibrosis, wound healing and vascularization (fibronectin, tenascin-C, vimentin, α-SMA and caveolin-1), cell division (Ki-67) and macrophages (CD68) were used. Naïve ARK, KLAL ARK corneas and transplanted corneal buttons presented similar histopathological changes with irregular epithelium and disruption or absence of epithelial basal membrane. There was a loss of the orderly pattern of collagen lamellae and absence of collagen I in all ARK corneas. Vascularization was revealed by the presence of caveolin-1 and collagen IV in the pannus of all ARK aniridia corneas. The changes observed in decentered and centered transplants were analogous. CONCLUSIONS: Given the similar pathological features of all cases, conditions inherent to the host seem to play an important role on the pathophysiology of the ARK in the long run.

Risk factors for refractive error after cataract surgery: Analysis of 282 811 cataract extractions reported to the European Registry of Quality Outcomes for cataract and refractive surgery.

PURPOSE: To analyze risk factors for refractive error after cataract surgery and provide a benchmark for refractive outcomes after standard cataract surgery. SETTING: One hundred cataract surgery clinics from 12 European countries. DESIGN: Multicenter database study. METHODS: Data on consecutive cataract extractions reported to the European Registry of Quality Outcomes for Cataract and Refractive Surgery between January 1, 2014 and December 31, 2015 were analyzed in terms of demographics, preoperative corrected distance visual acuity (CDVA), target refraction, coexisting eye diseases, surgical difficulties including previous ophthalmic interventions, type of surgery, intraocular lens (IOL), and surgical complications. For clinics committed to reporting follow-up data within 7 to 60 days after surgery, postoperative CDVA and refraction were analyzed. RESULTS: Of the 548 392 cases analyzed, follow-up data were available for 282 811 cases. The absolute mean biometry prediction error in spherical equivalent was 0.42 diopters (D). A biometry prediction error within ±0.50 D was achieved for 205 675 eyes (72.7%). A biometry prediction error within ±1.0 D was achieved for 263 015 eyes (93.0%). Poor preoperative CDVA, target refraction, coexisting eye diseases, surgical difficulties including previous ophthalmic interventions, and surgical complications were in varying degrees related to a postoperative refractive error. CONCLUSIONS: Several risk factors (poor preoperative CDVA, ocular comorbidity, and previous eye surgery) were related to poor refractive outcomes after cataract extraction. When these risk factors are present, care should be taken with the preoperative examination and choice of IOL to avoid a refractive surprise. The average outcomes can be used as a refractive outcome benchmark.

Transplanting embryonic stem cells onto damaged human corneal endothelium.

AIM: To investigate whether human embryonic stem cells (hESCs) could be made to attach, grow and differentiate on a human Descemet's membrane (DM). METHODS: Spontaneously differentiated hESCs were transferred onto a human corneal button with the endothelial layer removed using ocular sticks. The cells were cultured on a DM for up to 15 d. The genetically engineered hESC line expressed green fluorescent protein, which facilitated identification during the culture experiments, tissue preparation, and analysis. To detect any differentiation into human corneal endothelial-like cells, we analysed the transplanted cells by immunohistochemistry using specific antibodies. RESULTS: We found transplanted cells form a single layer of cells with a hexagonal shape in the periphery of the DM. The majority of the cells were negative for octamer-binding transcription factor 4 but positive for paired box 6 protein, sodium potassium adenosine triphosphatase (NaKATPase), and Zona Occludens protein 1. In four of the 18 trials, the transplanted cells were found to express CK3, which indicates that the stem cells differentiated into corneal epithelial cells in these cases. CONCLUSION: It is possible to get cells originating from hESCs to become established on a human DM, where they grow and differentiate into corneal endothelial-like cells in vitro.

Femtosecond laser-assisted cataract surgeries reported to the European Registry of Quality Outcomes for Cataract and Refractive Surgery: Baseline characteristics, surgical procedure, and outcomes.

PURPOSE: To describe a large cohort of femtosecond laser-assisted cataract surgeries in terms of baseline characteristics and the related outcomes. SETTING: Eighteen cataract surgery clinics in 9 European countries and Australia. DESIGN: Prospective multicenter case series. METHODS: Data on consecutive eyes having femtosecond laser-assisted cataract surgery in the participating clinics were entered in the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO). A trained registry manager in each clinic was responsible for valid reporting to the EUREQUO. Demographics, preoperative corrected distance visual acuity (CDVA), risk factors, type of surgery, type of intraocular lens, visual outcomes, refractive outcomes, and complications were reported. RESULTS: Complete data were available for 3379 cases. The mean age was 64.4 years ± 10.9 (SD) and 57.8% (95% confidence interval [CI], 56.1-59.5) of the patients were women. A surgical complication was reported in 2.9% of all cases (95% CI, 2.4-3.5). The mean postoperative CDVA was 0.04 ± 0.15. logarithm of the minimum angle of resolution. A biometry prediction error (spherical equivalent) was within ±0.5 diopter in 71.8% (95% CI, 70.3-73.3) of all surgeries. Postoperative complications were reported in 3.3% (95% CI, 2.7-4.0). Patients with good preoperative CDVA had the best visual and refractive outcomes; patients with poor preoperative visual acuity had poorer outcomes. CONCLUSIONS: The visual and refractive outcomes of femtosecond laser-assisted cataract surgery were favorable compared with manual phacoemulsification. The outcomes were highly influenced by the preoperative visual acuity, but all preoperative CDVA groups had acceptable outcomes.

Femtosecond laser-assisted cataract surgery versus standard phacoemulsification cataract surgery: Study from the European Registry of Quality Outcomes for Cataract and Refractive Surgery.

PURPOSE: To compare the visual, refractive, and adverse outcomes of femtosecond laser-assisted cataract surgery and conventional phacoemulsification cataract surgery. SETTING: Cataract surgery clinics in 9 European countries and Australia (femtosecond-assisted) and 18 European countries and Australia (conventional). DESIGN: Multicenter case-control study. METHODS: Eyes having femtosecond laser-assisted cataract surgery were matched to eyes from the European Registry of Quality Outcomes for Cataract and Refractive Surgery phacoemulsification cataract surgery database for preoperative corrected distance visual acuity (CDVA), age, and preoperative risk factors. Intraoperative and postoperative complications, postoperative CDVA, and refractive outcome were compared. The follow-up was 7 to 60 days. RESULTS: The study matched 2814 femtosecond-assisted cases to 4987 conventional phacoemulsification cases. Femtosecond-assisted surgery compared as follows to conventional phacoemulsification: posterior capsule complications, 0.7% versus 0.4%; postoperative logMAR CDVA, 0.05 (6/6-3) versus 0.03 (6/6-2); worse postoperative CDVA at follow-up (by 5 letters or more), 1.0% versus 0.4%; CDVA 0.3 (6/12) or better, 96.3% versus 97.1%; absolute biometry prediction error, 0.43 diopter (D) versus 0.40 D; within ±0.5 D of target, 72% versus 74.3%; and postoperative complications, 3.4% versus 2.3%. CONCLUSIONS: Femtosecond laser-assisted cataract surgery did not yield better visual or refractive outcomes than conventional phacoemulsification cataract surgery. Intraoperative complications were similar and low in both groups. Postoperative complications were lower in conventional phacoemulsification cataract surgery. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.