Proposed Section Structure
1. Highlights
2. Clinical and Policy Background
3. Study Design and Methods
4. Main Results
5. Why the Findings Matter for Quality Measurement
6. Strengths and Limitations
7. Clinical and Policy Implications
8. Conclusion
9. Funding, Registration, and References
Highlights
In a multicenter retrospective cohort of 55,132 patients undergoing cataract surgery across 16 health systems, 90.7% achieved the Merit-Based Incentive Payment System (MIPS) measure 191 definition of success: best recorded visual acuity of at least 20/40 within 90 days after surgery.
When patients with preexisting chronic ocular disease specified by the metric were excluded, the success rate rose to 95.5%. However, this exclusion removed 46.4% of surgical patients, raising important concerns about representativeness and fairness.
Lower odds of meeting the metric were associated with living in the least affluent communities, complex cataract surgery, combined cataract and other intraocular surgery, and diabetes. These findings indicate that nonclinical and clinical case-mix factors influence measured performance.
The study strongly suggests that MIPS measure 191, although intuitively attractive and easy to understand, may not be sufficient as a stand-alone benchmark for comparing surgeons or informing reimbursement without appropriate risk adjustment.
Clinical and Policy Background
Cataract surgery is among the most commonly performed operations in medicine and is generally highly successful in restoring vision. Because of its volume, predictable goals, and broad public health importance, cataract surgery has become a natural target for quality measurement. In the United States, the Centers for Medicare & Medicaid Services uses the Merit-Based Incentive Payment System to evaluate clinician performance and, increasingly, to shape payment incentives.
MIPS measure 191, titled “Cataracts: 20/40 or Better Visual Acuity Within 90 Days Following Cataract Surgery,” was designed to capture a patient-centered postoperative outcome that clinicians, payers, and patients readily understand. Achieving 20/40 vision is clinically meaningful because it approximates a threshold for many daily functions, including driving eligibility in many jurisdictions. On its face, the metric appears simple, objective, and relevant.
Yet the appeal of a quality measure does not guarantee that it is valid, generalizable, or equitable. Outcome measures can be distorted by differences in patient case mix, preexisting disease burden, social determinants of health, and procedure complexity. A surgeon caring for older, sicker, or socioeconomically disadvantaged patients may appear to perform worse even when delivering excellent care. Conversely, exclusion criteria can improve apparent performance rates while narrowing the population so substantially that the metric becomes less useful for judging real-world practice.
These concerns are especially important in ophthalmology, where many patients undergoing cataract surgery have concurrent retinal disease, glaucoma, corneal pathology, diabetic eye disease, or other conditions that affect postoperative visual acuity independently of surgical technical quality. The present study from the Sight Outcomes Research Collaborative (SOURCE) directly addresses whether MIPS measure 191 validly reflects cataract surgery quality across diverse practice settings and patient populations.
Study Design and Methods
Li and colleagues conducted a retrospective cohort study using electronic health record data from 16 participating health systems within SOURCE. The cohort included patients who underwent at least one cataract surgery between 2010 and 2023. For patients who had surgery in both eyes, only the first-eye procedure was analyzed to avoid correlated observations.
The primary endpoint was “surgical success” as defined by MIPS measure 191: best recorded visual acuity of at least 20/40 within 90 days after cataract surgery. The investigators assessed this outcome in the full cohort and in a restricted cohort excluding patients with preexisting chronic ocular diseases specified by the measure.
The analysis also explored how performance changed under more stringent visual acuity cutoffs and different follow-up windows. This is methodologically important because a quality metric can look stable or unstable depending on the threshold chosen and whether sufficient follow-up is available for postoperative refractive stabilization and visual rehabilitation.
To identify determinants of measured success, the authors used logistic regression models incorporating demographic variables, community-level affluence, and clinical characteristics such as diabetes, procedure complexity, and whether cataract surgery was combined with another intraocular operation. Data analysis was conducted from June 2024 to December 2025.
The final sample included 55,132 patients, with a mean age of 70.3 years. Women comprised 58.5% of the cohort. Race and ethnicity were self-reported: 3.6% Asian American, 12.8% Black, 3.6% Hispanic, and 76.5% White. The multicenter nature of the dataset strengthens the study’s external relevance compared with single-center reports, although it still reflects health systems participating in a collaborative registry rather than all U.S. practice environments.
Main Results
The overall message is that cataract surgery outcomes were excellent, but the quality measure itself has important structural limitations.
Overall success rates were high
Among all 55,132 patients undergoing surgery, 49,979 achieved the MIPS-defined success endpoint, yielding an overall success rate of 90.7%. This finding is reassuring and broadly consistent with the clinical reality that modern cataract surgery delivers substantial visual benefit for most patients.
When the cohort was limited to patients without the ocular comorbidities specified in the metric, 28,242 of 29,569 patients met the endpoint, for a success rate of 95.5%. In other words, the measure performs very well in a selected lower-risk population.
Nearly half of real-world patients were excluded
The most striking limitation of MIPS measure 191 was not that success rates were low, but that 25,563 patients, or 46.4% of all surgical recipients, were excluded once ocular comorbidity criteria were applied. A metric that removes nearly half of treated patients may have reduced value for evaluating broad surgical quality in contemporary practice.
The abstract further notes that older patients and Black patients were more likely to be excluded. This is a critical health equity signal. Exclusion patterns that disproportionately affect certain demographic groups can inadvertently narrow accountability for outcomes in populations that already face disparities in access, disease severity, or longitudinal care.
Sociodemographic and clinical factors influenced the odds of success
Several factors were independently associated with lower odds of meeting the 20/40 benchmark.
Patients living in the least affluent communities had lower odds of success compared with those in the most affluent communities (odds ratio [OR], 0.81; 95% CI, 0.72-0.91). This suggests that community-level socioeconomic context, likely acting through a combination of baseline disease burden, access to follow-up, ocular surface disease management, refractive correction, or other care processes, affects measured postoperative outcomes.
Complex cataract surgery was also associated with lower odds of success (OR, 0.82; 95% CI, 0.75-0.89). This is clinically plausible. Complex cases may involve small pupils, zonular weakness, pseudoexfoliation, dense lenses, prior ocular surgery, or intraoperative challenges that increase the technical difficulty and may limit short-term visual recovery despite appropriate management.
The strongest negative association was observed for combined cataract surgery with another intraocular procedure (OR, 0.32; 95% CI, 0.29-0.35). This is unsurprising. Patients selected for combined procedures often have concomitant pathology, such as glaucoma or retinal disease, which affects postoperative visual acuity and is not fully attributable to the cataract operation itself.
Diabetes was associated with lower odds of success (OR, 0.90; 95% CI, 0.84-0.98). Although the effect size was modest, it is clinically meaningful at the population level. Diabetes can impair outcomes through diabetic retinopathy, diabetic macular edema, corneal surface abnormalities, and slower visual rehabilitation.
Interpretation of effect sizes
Importantly, these associations do not imply poor surgical care in these subgroups. Rather, they show that the measured outcome is influenced by patient and procedural complexity. A surgeon with a high-volume referral practice for complicated cataract cases, or one serving socioeconomically disadvantaged communities, may appear to underperform if crude success percentages are compared without adjustment.
Why the Findings Matter for Quality Measurement
This study moves beyond the usual description of postoperative vision outcomes and asks a more policy-relevant question: does this metric fairly evaluate clinicians? The answer appears to be, only partially.
MIPS measure 191 has several strengths. It is based on an outcome rather than a process. It uses a clinically meaningful visual threshold. It is straightforward for stakeholders to understand. And the high rates of postoperative 20/40 vision support the view that cataract surgery remains a highly effective intervention.
However, three major concerns emerge.
First, the exclusion burden is substantial. A measure that omits nearly half of cataract surgery patients risks evaluating performance in a selectively healthy subgroup rather than in routine clinical practice. This may weaken generalizability and reduce the usefulness of the metric for health system accountability.
Second, the measure appears sensitive to social and clinical case mix. Community affluence, diabetes, and procedural complexity all affected the odds of success. These are not random variables, and they often cluster in practices serving vulnerable populations. Without robust risk adjustment, the metric could penalize clinicians who care for more complex or disadvantaged patients.
Third, the endpoint may not fully capture the multidimensional goals of cataract surgery. Visual acuity is important, but patients also care about contrast sensitivity, glare, anisometropia, spectacle dependence, visual function, and quality of life. Some patients may not reach 20/40 because of noncataract ocular disease yet still experience substantial benefit from surgery. Conversely, reaching 20/40 does not necessarily mean an optimal refractive or functional result.
Strengths and Limitations
Strengths
The study has several notable strengths. Its sample size was large, exceeding 55,000 patients. It drew on data from 16 health systems, improving geographic and practice diversity compared with single-institution analyses. The use of real-world electronic health record data enhances practical relevance because MIPS measures are applied in exactly these clinical environments rather than idealized trial settings.
The authors also evaluated the metric both in the full cohort and in the measure-eligible subgroup, which is essential for understanding how exclusion rules alter apparent performance. Their modeling of social and clinical predictors of success adds policy depth and supports the call for case-mix adjustment.
Limitations
As a retrospective observational study, the analysis is subject to residual confounding and variation in documentation. Best recorded visual acuity within 90 days may depend on when follow-up occurred, whether refractive correction was finalized, and how consistently acuity was measured across sites. Electronic health record data may incompletely capture ocular comorbidities or social risk factors.
The study assessed only the first operated eye, which is methodologically reasonable but does not fully represent bilateral surgical care. Also, the abstract does not provide surgeon-level variation or formal discrimination statistics for the metric, which would further clarify how well MIPS measure 191 distinguishes true performance differences from noise or case-mix effects.
Finally, although SOURCE includes multiple health systems, it may not perfectly represent all U.S. ophthalmology settings, especially smaller community practices, ambulatory surgery-heavy environments, or safety-net institutions with different follow-up patterns.
Clinical and Policy Implications
For clinicians, the main practical takeaway is that cataract surgery outcomes remain excellent, but raw postoperative 20/40 rates should be interpreted cautiously. Surgeons should not assume that a lower measured score necessarily reflects inferior technical care; it may instead reflect more complex patient populations.
For payers and policymakers, the study supports incorporating case-mix adjustment into quality assessment. At minimum, adjustment should account for ocular comorbidity, procedure complexity, combined surgery, diabetes, and markers of social risk. Without this, public reporting or payment consequences tied to MIPS measure 191 may create perverse incentives, including avoidance of high-risk patients.
For quality-improvement leaders, the findings suggest a more nuanced framework for cataract outcomes. A future measure set could combine risk-adjusted visual acuity outcomes with complication rates, patient-reported outcome measures, refractive accuracy, and follow-up completion. Such a multidomain approach would better align with the realities of modern cataract care.
For equity-focused stakeholders, the observation that older patients and Black patients were more likely to be excluded deserves close attention. If vulnerable groups are systematically removed from quality measurement, disparities may be obscured rather than addressed. A fair metric should reflect both inclusiveness and appropriate adjustment.
Conclusion
This study provides timely evidence that MIPS measure 191 captures an important truth and an important distortion at the same time. The truth is that most patients undergoing cataract surgery achieve good postoperative visual acuity, with 90.7% reaching at least 20/40 overall and 95.5% doing so in the measure-eligible subgroup. The distortion is that the metric excludes nearly half of real-world patients and is meaningfully influenced by socioeconomic and clinical case mix.
As a result, MIPS measure 191 may be acceptable as a descriptive outcome measure but insufficient as a stand-alone instrument for comparing surgeon performance or determining reimbursement. Risk adjustment and broader outcome frameworks are likely necessary to ensure validity, fairness, and equity in cataract surgery quality assessment.
Funding, Registration, and References
Funding information was not provided in the abstract supplied here. No ClinicalTrials.gov registration applies to this retrospective cohort study.
References:
1. Li Y, French DD, Chaudhury AS, Gaddam S, Andrews CA, Marwah S, Rivera AS, Zhou X, Evans CT, Bryar PJ, Stein JD; Sight Outcomes Research Collaborative (SOURCE) Consortium. Evaluating Metrics Assessing Surgical Success in Patients Undergoing Cataract Surgery. JAMA Ophthalmology. Published online April 16, 2026. PMID: 41989790.
2. American Academy of Ophthalmology Preferred Practice Pattern Cataract/Anterior Segment Panel. Cataract in the Adult Eye Preferred Practice Pattern. San Francisco, CA: American Academy of Ophthalmology. Current online guideline version available through the AAO website.
3. Centers for Medicare & Medicaid Services. Merit-Based Incentive Payment System (MIPS): 2024 Measure Specifications for Cataracts: 20/40 or Better Visual Acuity Within 90 Days Following Cataract Surgery, Measure 191. CMS quality payment program documentation.