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

METHODS

The EUREQUO was instituted in 2008 as a coproject between the European Union and the ESCRS and has been described extensively in the literature.^6,7 Mandatory parameters included in the EUREQUO and to be reported are as follows—patient-related parameters: patient number, year of birth, sex, and eye; preoperative parameters: corrected distance visual acuity (CDVA), biometry target refraction, coexisting eye disease (none, glaucoma, macular degeneration, diabetic retinopathy, amblyopia, and other), complicating comorbidity (none, previous corneal refractive surgery, white cataract, pseudoexfoliation, previous vitrectomy, corneal opacities, small pupil/intraoperative floppy iris syndrome, and other); intraoperative parameters: date of surgery, surgeon experience, type of operation, laser-assisted cataract surgery details, type of intraocular lens (IOL) optic biomaterial, and complications during surgery; and postoperative parameters: date of examination, CDVA of operated eye, and postoperative complications. This study analyzed the preoperative, intraoperative, and postoperative parameters over time. Preoperative parameters were age, sex, visual acuity, target refraction, and risk factors including ocular comorbidity and surgical difficulties; intraoperative parameters were anesthesia, surgical technique, IOL optic biomaterial, and surgical complications; and postoperative parameters were visual acuity, refraction, and short-term complications. Some parameters had different denominators because they were not available in all reporting national registries affiliated to EUREQUO. All data reported to the EUREQUO are anonymized. This study was approved by the Swedish Ethical Board (ref. number2020-01872) and was performed according to the tenets of the Declaration of Helsinki.

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 from 14 to 16 countries per year.

DISCUSSION

This study showed a significant decrease in the mean age of cataract surgery patients, from 74.5 years in 2008 to 73.0 years in 2017. This is close to the mean age of 73.2 years reported from Poland in 2010 to 2015 based on more than 1 million cataract extractions, although that study demonstrated no clear trend over the period.⁹ In a previous publication from the European Cataract Outcome Study (ECOS), the mean age of patients was 73.7 years at time of surgery.¹⁰ In this study, the proportion of women undergoing cataract extraction decreased significantly during the study period from 60.6% to 57.2%, whereas the proportion in the Polish study was fairly stable around 65.1%, and the ECOS study showed a proportion of 65.7% for 1 study year.^9,10 The relationship between age and sex distribution might be influenced by the difference in life expectancy between the sexes.¹¹ Another factor might be different patterns in requesting second-eye surgery.¹²

Risk factors for ocular comorbidity showed a decreasing trend in our study. The mean occurrence of glaucoma in the surgery eye (from 7.8% to 6.6%) was in line with that of reports from the Malaysian national cataract registry (6.4%), but lower than that of reports from Israel (14%).^13,14 Our finding of diabetic retinopathy in approximately 3% of eyes operated on for cataract is much lower than that reported from the Malaysian cataract register (approximately 10%), which might be due to the well-known high incidence of diabetes in Malaysia.¹⁵ These differences reflect the fact that different countries in different parts of the world might have great differences in baseline factors for cataract surgery patients. Our results offer a snapshot of cataract surgery practice from many surgeons and clinics in European countries.

These data show a clear transition from anesthetic injections to topical anesthesia. The same trend has been documented in surveys of preferred cataract surgery practices.¹⁶ The drop in intracameral anesthesia from 2015 and onward reflects a change in contributing country data.

Most surgeries reported in this study were phacoemulsification with implanted IOL, and this was stable over time. According to the coding guidelines, combined surgeries (cataract extraction plus vitrectomy or corneal transplantation) should not be reported to the registry. The only exception is a cataract extraction combined with a filtering procedure; this kind of surgery declined in frequency over time in this study. A low percentage of laser-assisted femtosecond cataract extraction has been reported since 2012. For 3 years between 2013 and 2015, the EUREQUO received data from a femtosecond laser–assisted cataract surgery study, which explains the increase of this surgical type in the registry.⁸ The study protocol included meticulous reporting of complications, which also affected the reporting of surgical and postoperative complications in these years.

Regarding choice of IOL, the registry includes type of optic biomaterial and different kinds of nonmonofocal IOLs (multifocal and toric IOLs). Hydrophobic acrylic IOLs dominate the material and their use has increased over time, whereas use of silicon and PMMA IOLs has declined to nearly zero. Biomaterial in IOLs has usually been studied with a focus on complications such as PCO, anterior capsule opacification, and glistening formation. The increase in the use of hydrophobic acrylic IOLs in this study is not surprising because the literature shows that this biomaterial is less related to anterior capsule opacification or PCO.¹⁷ On the other hand, the material also seems related to glistening, even if this complication seldom affects visual acuity.¹⁷ The number of nonmonofocal IOLs implanted was surprisingly low in this study, given the huge focus on these IOLs in the literature. The EUREQUO database is dominated by Dutch and Swedish data, and our interpretation is that nonmonofocal IOLs are mostly used in refractive lens exchange surgeries in these countries and not within ordinary cataract surgery. However, the frequency of these IOLs did increase over time in this study.

Capsule complications during surgery showed a decreasing trend in our study. A similar trend has also been reported from other registries collecting data over time.¹⁸ Although findings regarding surgical complications might be flawed by underreporting, we think that this decreasing trend is a solid finding.¹⁸ Reasons for this positive development might include better surgical quality and surgery on younger and healthier eyes. Our finding of decreasing complications regarding dropped nucleus has been extensively discussed in a previous article.⁷

The visual outcome in mean CDVA improved over time in our study. In a previous article, we discussed the visual outcome and the baseline parameters that influenced it.¹⁹ The refractive outcome also showed an improving trend during the study period. Reasons for a poor refractive outcome based on data from the EUREQUO have been reported previously.⁶

The postoperative complications in our study must be seen in the light of a 30-day follow up, which prevents late complications such as PCO from being represented in a fair way. The reported frequency of postoperative endophthalmitis showed a decreasing trend from approximately 0.05% to 0.02%, which again must also be seen in the light of the mean follow-up time. A weakness in our registration is the lack of information about preventive measures such as asepsis and intracameral antibiotic injection. However, we know from other sources that most surgeons in the Netherlands and Sweden use intracameral antibiotics as a prophylactic regimen.^20,21

Another weakness of our study is the fact that the data were self-reported by surgeons and clinics. We believe, however, that the data are reliable because the reason for surgeons to participate is benchmarking and comparison, and each surgeon’s or clinic’s data are only visible to themselves. Finally, the registry protocol includes a limited number of parameters and a limited follow-up time, to reduce the clinical burden of reporting data. A strength of our study is the large number of reported cases from many countries for more than a decade.

Trends in European cataract surgery practice patterns from 2008 to 2017 as reflected in the EUREQUO have moved toward slightly younger patients with better preoperative visual acuity, fewer surgical complications, and better visual outcomes and less absolute prediction error.