Findings from a study published in Eye led to the development of a risk factor model for posterior capsule rupture (PCR) during cataract surgery using data from the Royal College of Ophthalmologists’ National Ophthalmology Database (RCOphth NOD).
First off, what is the RCOphth NOD?
Since its inception in 2010, the RCOphth NOD audit has established itself to be an important quality assurance measure and research tool, with 16 reports published prior to this one.
Keep going…
PCR remains one of the most common complications of cataract surgery and is a risk factor for poor visual prognosis.
Consequently, researchers sought to update the now 15-year-old stratification system for PCR from the previous Cataract National Dataset and the RCOphth NOD PCR risk adjustment model created in 2015.
- Note: Over this time period, PCR rates have more than halved—from 1.95% to 0.87%— in the latest RCOphth NOD audit annual report for 2021-2022.
Now talk about the study.
Eligible cataract operations were performed between April 1, 2016 and March 31, 2022, in centers supplying data to the national cataract audit on at least 60 eligible operations with complete data.
Data was considered complete if it included:
- Patient’s gender and age at surgery
- Anterior chamber depth (ACD) measurement
- Preoperative visual acuity (VA)
With this data, the research team performed a logistic regression model to identify risk factors for PCR.
Findings?
This analysis included 961,208 cataract operations performed on 682,381 patients from 136 participating centers by 3,198 surgeons.
In total, 9,730 (1.01%) cataract surgeries were complicated by PCR, with a median age of 75.7 and 76.7 years for the first and second eye surgery, respectively.
- In addition: 53.0% of patients who experienced PCR were female.
The most significant influencing risk factors for PCR were:
- Surgery by a less experienced trainee surgeon
- Odds ratio [OR] 3.75, 95% confidence interval [CI] 3.33-4.24, p < 0.001
- Presence of pseudoexfoliation/phacodonesis
- OR 3.47, 95% CI 3.05-3.94, p < 0.001
- Younger male patients
- OR 3.05, 95% CI 2.23-2.60, p < 0.001
- Brunescent/white/mature cataract
- OR 2.41, 95% CI 2.24-2.60, p < 0.001
Any other risk factors?
Additional factors that impacted the risk for PCR included:
- Glaucoma
- Worse preoperative VA
- Previous intravitreal therapy
- High myopia
- Previous vitrectomy
- Systemic diabetes
- Diabetic retinopathy
- Amblyopia
- Older age
- Shallower ACD
- Inability to lie flat and cooperate
Expert opinion?
While an elevated risk for PCR was observed in younger male patients, the interaction between age and gender interaction diminished this risk in older patients.
- By age 85, there was a parity in PCR risk between males and females, and above 90 years of age, females had a higher risk.
The study authors noted that the significantly higher rate of PCR in eyes with previous PPV could be due to:
- Altered fluid dynamics
- Unstable posterior capsules
- Posterior lenticular touch during vitrectomy
Further: The pathophysiology behind the increased risk of PCR in vitrectomized eyes may also have some overlap with that of high myopia, given the strong correlation between the two.
Were there any traits not included in the study?
Of note, axial length (AL) and social deprivation were not considered in this analysis:
- AL was not considered as it is correlated with ACD, and previous studies have shown that AL is not a significant influencer for PCR risk.
- Social deprivation was not considered because the audit did not receive this information from all contributing centers due to the differing data collection systems used.
Limitations?
These included:
- 40.8% of patients had bilateral cataract surgery, which could introduce patient-level correlation and impact the statistical comparisons
- Potentially not all recorded first-treated eye operations were the patients’ actual first eye surgery, as patients could have had the first procedure prior to a center adopting an electronic medical record (EMR) or performed at a different center
Take home.
These findings suggest that various surgical, patient, and ocular factors increase the risk of PCR during cataract surgery.
The risk factor model allows for the estimation of individualized risks for patients and allows for surgeons to make individualized adjustments to minimize the risk of PCR.