The Power of Registries

More than three decades of data from the Swedish National Cataract Registry suggest quality registries can provide important information on cataract surgery risk factors, especially for rare complications such as endophthalmitis, according to Madeleine Zetterberg MD, PhD.¹ These registries can enable better surgical planning and patient selection, which may lead to safer surgery with fewer complications and better outcomes.

“The general strategy [for boosting outcomes] is to get knowledge on how to choose the right patient at the right time point for surgery and the right procedure,” Professor Zetterberg said. “Choosing the right prophylaxis to control inflammation and prevent infection and the right intraocular lens are also critical, as is communicating with patients to establish realistic expectations, often leading to higher satisfaction.”

Originally founded in 1992 to track waiting times, the Swedish registry is now considered the most comprehensive record of cataract surgery anywhere in the world. It includes data on nearly 3 million procedures, currently covering about 93% of cataract surgeries performed at more than 100 surgical units nationwide. Over time, it has added features, including pre- and intraoperative data, outcomes and patient-reported outcomes (PROMs), and individual surgeon identifiers.

Data collected preoperatively includes keratometry, axial length, lens formula, and planned refraction. Postoperatively, keratometry is collected as well as best-corrected visual acuity (BCVA), refraction, type of IOL, type of surgery, and any need for further follow-up. PROMs are collected preoperatively and three months postoperatively. This makes the registry a valuable trove for driving and documenting quality improvement.

Steady progress

The registry shows consistent improvement in several outcomes over time, Prof Zetterberg noted. For example, the percentage of patients without comorbidities achieving postoperative BCVA of 0.8 decimal or better increased from about 70% in 1997 to close to 90% in 2020 and 2021, while the median BCVA increased from 0.8 to 1.0 in 2024. Similarly, biometry prediction errors declined, with only about 55% within 0.5 D from planned refraction in 1997 to about 75% in 2024. “The median biometry prediction error has been zero since 2006,” she said. 

PROMs have also improved, with both pre- and postoperative subjective visual function, as measured by the Catquest-9, gaining over time. When combined with other registry data, this has yielded valuable insights for selecting and counselling patients, Prof Zetterberg observed. Insights include: older patients benefit as much as younger patients; comorbidities are the most common cause of bad PROMs outcomes; surgery in both eyes gives better outcomes; age-related macular degeneration patients benefit significantly from cataract surgery; and subjective improvement lasts a long time after surgery. And, crucially, good preoperative BCVA decreases the risk of dissatisfaction.

Understanding complications

Complications also have declined, thanks in part to insights from the registry. One analysis found risk factors for posterior capsule rupture (PCR) include dense cataracts/use of Vision Blue, miosis/mechanical dilation, zonular weakness, inexperienced surgeons, and previous ocular trauma.² PCR rates have fallen from about 2.8% in 2002 to about 0.5% in 2024. Other registry studies suggest achieving a PCR rate of less than 1.0% requires surgeons to perform at least 400 procedures per year.^{3, 4} However, higher-volume surgeons tend to have a slightly lower case severity mix, which Prof Zetterberg said may contribute to their lower PCR rates.

Sweden has collected data on endophthalmitis in a separate registry since 1998, including patient identification and time point of diagnosis, culture results (including pathogen and susceptibility to antibiotics), and visual outcomes post-diagnosis. Findings helped spur the landmark ESCRS Endophthalmitis Study in 2007, which found intracameral antibiotics are effective in reducing incidence.⁵

Since records began, the rate of endophthalmitis in the registry has fallen from 0.10% to 0.01%. Of interest, the rate for immediate sequential bilateral cataract surgery has been lower than for unilateral surgery. In recent years, the registry has also documented a decline in cefuroxime use and an increase in moxifloxacin.

The Swedish National Cataract Registry also tracks comorbidities and their impact on outcomes and complications after cataract surgery, Prof Zetterberg said. Visual outcomes, patient satisfaction, and the need for additional procedures are all worse for patients with comorbidities ranging from glaucoma and macular disorders to corneal guttata and previous vitrectomy or refractive surgery. For example, patients with corneal guttata have about 68 times the rate of corneal transplants after cataract surgery as patients without.⁶

Real-world uses

Outcome data from the registry help individual surgeons monitor procedure volume, case mix, and complication rates, Prof Zetterberg said. For individual departments, the data are valuable for monitoring volume, providing information for decision making and quality control. At the national level, the data help develop evidence-based guidelines as well as plans for healthcare resources.

Future study topics include regional differences in access and outcomes, determining the optimal time for surgery, outcomes for diabetic patients, retinal detachment and PROMs, gender perspectives among surgeons, and new antibiotic regimens for preventing endophthalmitis.

“Quality registries may lead to safer surgery with fewer complications, which is especially good for rare complications, and it may enhance outcomes,” Prof Zetterberg concluded.

Prof Zetterberg spoke at the 2025 ESCRS Annual Congress in Copenhagen.

Madeleine Zetterberg MD, PhD is Senior Consultant and Head of Department at the Department of Ophthalmology, Sahlgrenska University Hospital/Mölndal and Professor at the Department of Clinical Neuroscience, University of Gothenburg, Sweden. madeleine.zetterberg@gu.se

1. Zetterberg M. “Boosting outcomes with surgical registries: Insights from the Swedish National Cataract Registry,” presented at the European Society of Cataract and Refractive Surgeons Annual Congress, Copenhagen, Denmark, 13 September 2025.

2. Lundstrom M, et al. J Cataract Refract Surg, 2009 Oct; 35(10): 1679–1687.

3. Zetterberg M, et al. Ophthalmology, 2020 Mar; 127(3): 305–314.

4. Zetterberg M, et al. Ophthalmology, 2021 Mar; 128(3): 364–371.

5. ESCRS Endophthalmitis Study Group. J Cataract Refract Surg, 2007 Jun; 33(6): 978–988.

6. Viberg A, et al. J Cataract Refract Surg, 2020 Jul; 46(7): 961–966.