Highlights
- Prior pars plana vitrectomy (PPV) is independently associated with a higher incidence of pseudophakic cystoid macular edema (CME) after cataract surgery.
- Risk of CME was approximately 3.7 times greater in eyes with prior PPV compared to non-vitrectomized eyes.
- This elevated risk persists across indications for vitrectomy, including retinal detachment and non-retinal detachment cases.
- Findings emphasize the need for vigilance in postoperative monitoring and consideration of prophylactic strategies in vitrectomized eyes undergoing cataract extraction.
Study Background and Disease Burden
Cataract surgery is one of the most frequently performed ophthalmic procedures worldwide, with generally excellent visual outcomes. However, postoperative complications such as pseudophakic cystoid macular edema (CME) can limit visual recovery and affect patient satisfaction. CME is characterized by fluid accumulation in the macular area leading to retinal swelling and visual impairment. Understanding risk factors for CME is crucial to optimize preoperative planning and postoperative care.
Pars plana vitrectomy (PPV) is a common vitreoretinal surgical procedure performed for diverse indications, including retinal detachment (RD), vitreous hemorrhage, and epiretinal membrane peeling. PPV alters vitreous dynamics, ocular inflammation, and blood-retinal barrier integrity, which might influence susceptibility to postoperative inflammation and CME.
Despite clinical observations suggesting increased CME risk in eyes with prior PPV undergoing cataract surgery, robust large-scale evidence has been lacking. This study aimed to fill that knowledge gap by analyzing associations between previous PPV and the incidence of postoperative CME using a large multicenter electronic health record database.
Study Design
This retrospective cohort study utilized data from the TriNetX US Network, a federated electronic health record repository encompassing academic and community hospitals across the United States, from December 2005 through December 2025.
The study population included adults aged 18 years and older who underwent cataract surgery. Patients were classified based on prior history of PPV performed at least six months before cataract surgery. Those with preexisting CME or other recognized CME risk factors were excluded to mitigate confounding.
The primary outcome measured was development of CME within 30 to 90 days after cataract surgery, identified using ICD-10 diagnostic codes. Risk ratios (RR) comparing CME incidence between patients with prior PPV versus those without were calculated. Propensity score matching adjusted for potential confounders including age, sex, race, hypertension, hyperlipidemia, diabetes, myopia, and history of retinal detachment.
Key Findings
From the initial cohort of 615,983 cataract surgery patients, 7,422 had history of PPV. After propensity score matching, 7,318 pairs were analyzed, yielding well-balanced demographic and clinical variables.
CME occurred in 4.59% of eyes with prior PPV versus 1.23% in non-PPV controls. This corresponded to an absolute risk difference of 3.36% (95% CI, 2.82%-3.90%) and a relative risk of 3.73 (95% CI, 2.97-4.70; P < .001), demonstrating a statistically and clinically significant elevation in CME risk associated with PPV.
Subgroup analysis intensifying the indication for PPV revealed elevated CME risk irrespective of the indication. In eyes with prior PPV for retinal detachment, CME incidence was 5.65%, compared to 1.22% in controls (RR 4.62; 95% CI, 3.20-6.67; P < .001). For non-RD indications, CME incidence was 3.99% versus 1.23% (RR 3.26; 95% CI, 2.36-4.50; P < .001).
Importantly, elevated CME risk remained even after excluding patients who experienced intraoperative or postoperative cataract surgery complications, affirming that prior vitrectomy itself is a robust independent risk factor.
Expert Commentary
These findings underscore that eyes with prior PPV have markedly increased susceptibility to CME following cataract surgery. Vitrectomized eyes may have compromised vitreous scaffolding and altered intraocular milieu, resulting in enhanced macular vulnerability to postoperative inflammation and fluid accumulation.
However, reliance on ICD-10 coding for CME without confirmatory clinical or imaging data constitutes a significant limitation. Moreover, absence of visual acuity outcomes prevents assessment of CME severity and its functional impact.
The large sample size and rigorous propensity matching enhance study validity, yet residual confounding cannot be excluded. It remains unclear whether modified surgical techniques, intensified anti-inflammatory prophylaxis, or tailored postoperative monitoring could mitigate CME risk in this population. Thus, prospective studies integrating imaging and functional outcomes are warranted.
Conclusion
This large retrospective cohort study provides convincing evidence that prior pars plana vitrectomy independently increases the risk of pseudophakic cystoid macular edema after cataract surgery. The risk elevation spans different indications for vitrectomy and persists despite absence of surgical complications.
Clinicians should be aware of this risk when counseling patients with prior PPV and consider proactive monitoring and anti-inflammatory strategies to optimize visual outcomes. Further research is necessary to define optimal management pathways for these higher-risk eyes.
Funding and Clinical Trials
The study did not report external funding sources. It was based on de-identified electronic health record data from the TriNetX network.
References
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