Abstract
Purpose:
To determine recent incidence and visual outcomes for acute-onset endophthalmitis after cataract surgery performed in the United States.
Design:
Retrospective cohort study.
Participants:
United States cataract surgery patients, 2013–2017 (5 401 686 patients).
Methods:
Cases of acute-onset postoperative endophthalmitis occurring within 30 days after cataract surgery were identified using diagnosis codes in the American Academy of Ophthalmology IRIS (Intelligent Research in Sight) Registry database, drawn from electronic health records in ophthalmology practices across the nation. Annual and aggregate 5-year incidences were determined for all cataract surgeries and specifically for standalone procedures versus those combined with other ophthalmic surgeries. Patient characteristics were compared. Mean and median visual acuity was determined at 1 month preoperative as well as 1 week, 1 month, and 3 months postoperative among patients with and without endophthalmitis.
Main Outcome Measures:
Incidence of acute-onset postoperative endophthalmitis after cataract surgery.
Results:
A total of 8 542 838 eyes underwent cataract surgery, 3629 of which developed acute-onset endophthalmitis (0.04%; 95% confidence interval, 0.04%–0.04%). Endophthalmitis incidence was highest among patients aged 0 to 17 years (0.37% over 5 years), followed by patients aged 18 to 44 years (0.18% over 5 years; P < 0.0001). Endophthalmitis occurred 4 times more often after combined cases (cataract with other ophthalmic procedures) than after standalone cataract surgeries (0.20% vs. 0.04% of cases), and occurred in 0.35% of patients receiving anterior vitrectomy. Mean 3-month postoperative visual acuity was 20/100 (median, 20/50) among endophthalmitis patients, versus a mean of approximately 20/40 (median, 20/30) among patients without endophthalmitis. However, 4% of endophthalmitis patients still achieved 20/20 or better visual acuity, and 44% achieved 20/40 or better visual acuity at 3 months.
Conclusions:
Acute-onset endophthalmitis occurred in 0.04% of 8 542 838 cataract surgeries performed in the United States between 2013 and 2017. Risk factors may include younger age, cataract surgery combined with other ophthalmic surgeries, and anterior vitrectomy. Visual acuity outcomes vary; however, patients can recover excellent vision after surgery. Big data from clinical registries like the IRIS Registry has great potential for evaluating rare conditions such as endophthalmitis, including developing benchmarks, longer-term time trend investigation, and comprehensive analysis of risk factors and prophylaxis.
Cataract surgery dramatically improves vision and quality of life and can be performed quickly and safely in most cases.1–3 However, devastating—although rare—complications such as acute-onset postoperative endophthalmitis can still occur. Endophthalmitis carries a substantial public health burden, requiring patients to undergo more physician visits and procedures (including potentially returning to the operating room for a pars plana vitrectomy), resulting in higher health care costs, and frequently yielding reduced vision and impaired quality of life.4–8
Numerous existing studies have retrospectively evaluated the incidence of endophthalmitis occurring after cataract surgery,9 primarily based on administrative claims data and data from single centers or health care systems. Incidence estimates range from 0.02% to 0.2%,5–22 with increasing rates in the late 1990s and early 2000s that have been attributed to the rising use of clear corneal incisions and a subsequent decline in the 2010s that has been credited to greater use of intracameral antibiotics. For example, a recent French study found an increase in the use of intracameral antibiotics from less than 1% of cases in 2005 to 80% of cases in 2014, with a corresponding decrease in endophthalmitis incidence from 0.15% to 0.05% over the same period.19 However, some controversy remains, with others pointing out that factors such as improved equipment, surgical techniques, or new topical antibiotic regimens may also play a role in reduced rates of endophthalmitis.21
Data on visual outcomes after recovery from endophthalmitis remain limited. To date, one of the largest studies evaluated a subset of 615 Medicare beneficiaries with endophthalmitis. Most ended up with vision worse than 20/40, and 34% achieved a final visual acuity 20/200 or worse.6 In a series of 7 patients from a single academic center, 4 of 7 patients with endophthalmitis achieved a final visual acuity of 20/25 and the remaining 3 patients achieved visual acuity of no better than counting fingers.7
Endophthalmitis is difficult to study because of its very low incidence, and the potential costs of a large-scale, prospective study are prohibitive as well as potentially limited in generalizability. However, the American Academy of Ophthalmology Intelligent Research in Sight (IRIS) Registry is uniquely suited to study rare ophthalmic conditions and provide insight into real-world practice patterns and outcomes. In this analysis, the IRIS Registry database was used to evaluate the frequency of cataract surgery and acute-onset postoperative endophthalmitis, investigate differences in endophthalmitis rates between cataract surgery as a stand-alone versus a combined procedure, and report visual acuity outcomes among patients with endophthalmitis. These findings inform point-of-care conversations with patients about their risks and prognosis and provide a foundation for further research.
Methods
Data Source
Data for this analysis were derived from the American Academy of Ophthalmology IRIS Registry. Participation in the IRIS Registry has grown continuously since its inception in 2014, and as of January 1, 2019, it currently contains data on more than 52 million unique patients treated by approximately 15 000 physicians, representing most United States ophthalmologists with electronic health records (EHRs). The methods for the IRIS Registry have been described elsewhere.23 The IRIS Registry database includes patient demographics, insurance and provider geographic information, medications, past medical history, diagnoses, and procedures. Diagnoses are drawn primarily from International Classification of Diseases, 9th and 10th editions, codes, and procedures are identified primarily from Current Procedural Terminology codes and Healthcare Common Procedural Coding System codes. Unlike administrative claims, the data set also includes clinical information such as visual acuity, intraocular pressure, and laterality. This study included records from January 1, 2013, through December 31, 2017. Practices adhered to the tenets of the Declaration of Helsinki.
Sample Selection and Primary Outcome Measure
This analysis was limited to recorded episodes of cataract surgery. Cases were divided into cataract surgery alone and cases combined with another intraocular surgery (including glaucoma surgery). Episodes of anterior vitrectomy and unplanned return to the operating room within 30 days were identified. Acute-onset postoperative endophthalmitis was identified by International Classification of Diseases, 9th and 10th editions, diagnosis codes, procedure codes for intravitreal antibiotic injection (Table S1, available at www.aaojournal.org), or both. Procedures were identified by relevant Current Procedural Terminology codes (Table S2, available at www.aaojournal.org) indicating procedure laterality (right, left, or both eyes). Each patient’s first documented cataract surgery code for a given eye during the observed study period was used to define the date of cataract surgery. Cases were subdivided into 10 geographic regions corresponding to Medicare regions and regional offices.
Statistical Analysis
The primary outcome of interest was acute-onset endophthalmitis after cataract surgery, identified by presence of a diagnosis or procedure indicating clinical signs of presumed endophthalmitis. Aggregate incidence and annual incidence rates for acute-onset endophthalmitis were evaluated by number of eyes in the IRIS Registry database. Patient characteristics (age, gender, race, and geographic region) were summarized using frequencies and percentages. Cataract surgery episodes were subdivided into cases of cataract surgery performed alone and those with cataract surgery performed in combination with other ocular procedures (e.g., glaucoma surgery). Rates of endophthalmitis within 30 days of surgery were compared by year for combined and stand-alone cases, and 95% confidence intervals were calculated based on the Poisson distribution using the exact method.24,25 Finally, visual outcomes were evaluated as mean and median measured best-corrected visual acuity measured at 4 time points: (1) before surgery (within 60 days before cataract surgery), (2) approximately 1 week (3–15 days) after cataract surgery, (3) approximately 1 month (16–42 days) after cataract surgery, and (4) approximately 3 months (43–120 days) after cataract surgery. Visual acuity measurements were matched by laterality to the surgical eye and excluded if they did not fall within a normal range (−0.3 to 1 logarithm of the minimum angle of resolution [logMAR]) or if laterality was unspecified. For patients with multiple visual acuity measurements for the surgical eye during a given period, the measurement closest to the desired date was selected for analysis (e.g., the closest measurement to the date of surgery for preoperative visual acuity, and the closest measurement to 7 days after surgery for 1-week postoperative visual acuity). In cases where multiple visual acuity measurements were recorded for the surgical eye on the same date, the mean of all measurements on that date was used for analysis. At each time point, visual acuity outcomes were compared for cataract surgery patients who demonstrated acute-onset endophthalmitis versus those who did not. For all analyses, P < 0.05 was considered statistically significant.
Results
Study Population and Rates of Acute-Onset Endophthalmitis
Review of the IRIS Registry database identified a total of 8 542 838 eyes among 5 401 686 patients undergoing cataract surgery during the study period (Table 1). The largest proportion of cases (39.7%) were in patients 65 to 74 years of age, and most were in female patients (58.8%). Most patients with reported race data were white (75.2%); however, 9.6% of patients did not have a recorded value for race in the EHR.
Table 1.
Demographics and Clinical Characteristics for Cataract Surgery and Endophthalmitis Cases from the American Academy of Ophthalmology Intelligent Research in Sight Registry, 2013–2017
| Cataract Surgery* |
Endophthalmitis† |
|||||
|---|---|---|---|---|---|---|
| No. | % | No. | % | 95% Confidence Interval | P Value‡ | |
| Year | <0.0001 | |||||
| 2013 | 1 192 704 | 13.96 | 435 | 0.04 | 0.03–0.04 | |
| 2014 | 1 479 576 | 17.32 | 523 | 0.04 | 0.03–0.04 | |
| 2015 | 1 741 544 | 20.39 | 704 | 0.04 | 0.04–0.04 | |
| 2016 | 1 997 218 | 23.38 | 885 | 0.04 | 0.04–0.05 | |
| 2017 | 2 131 796 | 24.95 | 1082 | 0.05 | 0.05–0.05 | |
| Age (yrs)§ | <0.0001 | |||||
| 0–17 | 5648 | 0.07 | 21 | 0.37 | 0.23–0.57 | |
| 18–44 | 63 941 | 0.75 | 112 | 0.18 | 0.14–0.21 | |
| 45–64 | 1 416 967 | 16.59 | 673 | 0.05 | 0.04–0.05 | |
| 65–74 | 3 389 290 | 39.67 | 1267 | 0.04 | 0.04–0.04 | |
| 75–84 | 2 863 447 | 33.52 | 1150 | 0.04 | 0.04–0.04 | |
| 85+ | 802 717 | 9.40 | 404 | 0.05 | 0.05–0.06 | |
| Gender‖ | <0.0001 | |||||
| Male | 3 505 684 | 41.04 | 1746 | 0.05 | 0.05–0.05 | |
| Female | 5 022 526 | 58.79 | 1882 | 0.04 | 0.04–0.04 | |
| Race¶ | <0.0001 | |||||
| White | 6 422 490 | 75.18 | 2889 | 0.04 | 0.04–0.05 | |
| Black | 505 136 | 5.91 | 337 | 0.07 | 0.06–0.07 | |
| Asian | 183 215 | 2.14 | 85 | 0.05 | 0.04–0.05 | |
| American Indian | 32 604 | 0.37 | 22 | 0.07 | 0.04–0.10 | |
| Native Hawaiian | 9513 | 0.11 | 6 | 0.06 | 0.02–0.14 | |
| Multiracial | 17 618 | 0.24 | 30 | 0.17 | 0.12–0.24 | |
| Other | 555 422 | 6.50 | 227 | 0.04 | 0.04–0.05 | |
| Medicare region#,** | <0.0001 | |||||
| 1 | 301 619 | 3.53 | 123 | 0.04 | 0.03–0.05 | |
| 2 | 679 483 | 7.95 | 252 | 0.04 | 0.03–0.04 | |
| 3 | 853 481 | 9.99 | 368 | 0.04 | 0.04–0.05 | |
| 4 | 1 974 772 | 23.12 | 905 | 0.05 | 0.04–0.05 | |
| 5 | 1 426 511 | 16.70 | 561 | 0.04 | 0.04–0.04 | |
| 6 | 1 059 288 | 12.40 | 437 | 0.04 | 0.04–0.05 | |
| 7 | 474 331 | 5.55 | 181 | 0.04 | 0.03–0.04 | |
| 8 | 239 994 | 2.81 | 85 | 0.04 | 0.03–0.04 | |
| 9 | 641 752 | 7.51 | 287 | 0.04 | 0.04–0.05 | |
| 10 | 436 462 | 5.11 | 214 | 0.05 | 0.04–0.06 | |
CI = confidence interval.
Results presented based on number of eyes (unique surgeries). Percentages are of the entire study population (all cataract surgeries over a 5-year period).
Results presented based on number of eyes (unique cases of endophthalmitis). Percentages represent the rate of endophthalmitis cases after cataract surgery within a given year (for 2013–2017) or over a 5-year period (for age, gender, race, and Medicare region).
P values calculated based on difference in proportions between all cataract surgeries and cataract surgeries with endophthalmitis.
Missing data on 828 eyes (0.01%).
Missing data on 14 628 eyes (0.17%).
Missing data on 817 840 eyes (9.57%).
Missing data on 455 145 eyes (5.33%).
Medicare region 1 = Connecticut, Massachusetts, Maine, New Hampshire, Rhode Island, and Vermont; region 2 = New Jersey, New York, Puerto Rico, and United States Virgin Islands; region 3 = Washington, DC, Delaware, Maryland, Pennsylvania, Virginia, and West Virginia; region 4 = Alabama, Florida, Georgia, Kentucky, Missouri, North Carolina, South Carolina, and Tennessee; region 5 = Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin; region 6 = Arkansas, Louisiana, New Mexico, Oklahoma, and Texas; region 7 = Iowa, Kansas, Missouri, and Nebraska; region 8 = Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming; region 9 = Arizona, California, Guam, Hawaii, and Nevada; and region 10 = Alaska, Idaho, Oregon, and Washington.
A total of 3629 eyes demonstrated acute-onset postoperative endophthalmitis (0.04%; 95% confidence interval, 0.04–0.04). A clinically significant difference in endophthalmitis rates was not observed across the years in the study period (Table 1). Incidence of endophthalmitis was highest among patients 0 to 17 years of age (0.37% over 5 years), followed by patients 18 to 44 years of age (0.18% over 5 years). Patients 0 to 17 years of age represented 0.20% of cataract surgeries but 1.04% of endophthalmitis cases. Those 85 years of age or older showed a similar incidence of endophthalmitis as those 45 to 64 years of age (0.05% for each). Endophthalmitis incidence was slightly higher in men than women (0.05% vs. 0.04%) and among multiracial (0.17%), black (0.07%), American Indian (0.07%), and Native Hawaiian (0.06%) patients. Endophthalmitis rates after cataract surgery did not vary substantially by geographic region, ranging from 0.04% to 0.05% (Table 1).
Endophthalmitis Rates after Cataract Surgery Combined with Other Ocular Procedures, including Glaucoma Surgeries and Anterior Vitrectomy
Acute-onset endophthalmitis occurred in 4 times as many patients undergoing cataract surgery combined with other ophthalmic procedures as in patients undergoing cataract surgery as a stand-alone procedure (0.20% of cases vs. 0.04%; Table 2). Among the subset of patients undergoing cataract surgery combined with glaucoma surgery, the aggregate rate of acute-onset endophthalmitis was 0.12%, and among patients undergoing anterior vitrectomy with cataract surgery, the endophthalmitis rate was 0.35%. A consistent trend in endophthalmitis rates over time was not observed for combined versus stand-alone surgery.
Table 2.
Rates of Endophthalmitis after Cataract Surgery Performed Alone and Combined with Other Ocular Procedures, 2013–2017
| Endophthalmitis after Cataract Surgery Alone |
Endophthalmitis after Cataract Surgery Combined with Any Other Ocular or Adnexal Procedure* |
Endophthalmitis after Cataract Surgery Combined with Glaucoma Surgery† |
Endophthalmitis after Cataract Surgery Requiring Anterior Vitrectomy‡ |
|||||
|---|---|---|---|---|---|---|---|---|
| Year | No. § | % (95% Confidence Interval) | No. § | % (95% Confidence Interval) | No. § | % (95% Confidence Interval) | No. § | % (95% Confidence Interval) |
| 2013 | 370 | 0.03 (0.03–0.03) | 65 | 0.18 (0.14–0.23) | 6 | 0.14 (0.05–0.30) | 5 | 0.34 (0.11–0.78) |
| 2014 | 438 | 0.03 (0.03–0.03) | 85 | 0.15 (0.12–0.18) | 9 | 0.14 (0.06–0.27) | 7 | 0.35 (0.14–0.72) |
| 2015 | 607 | 0.03 (0.03–0.04) | 97 | 0.16 (0.13–0.19) | 9 | 0.13 (0.06–0.25) | 6 | 0.27 (0.10–0.58) |
| 2016 | 734 | 0.04 (0.03–0.04) | 151 | 0.25 (0.21–0.29) | 3 | 0.04 (0.01–0.13) | 11 | 0.43 (0.21–0.77) |
| 2017 | 915 | 0.04 (0.04–0.05) | 167 | 0.25 (0.22–0.29) | 9 | 0.14 (0.07–0.27) | 9 | 0.34 (0.16–0.65) |
| All years | 3064 | 0.04 (0.04–0.04) | 565 | 0.20‖ (0.18–0.22) | 36 | 0.12¶ (0.08–0.16) | 38 | 0.35# (0.25–0.48) |
Defined by Current Procedural Terminology codes 67005 or 67010.
Results presented based on number of eyes (unique surgeries).
Defined by Current Procedural Terminology codes 65091–68899.
Defined by Current Procedural Terminology codes 66170, 66172, 66180, 66185, 66710, 66711, or 65850.
P < 0.0001 for a difference in endophthalmitis proportions between cataract surgery with other ocular or adnexal procedures versus cataract surgery as a standalone procedure.
P < 0.0001 for a difference in endophthalmitis proportions between cataract surgery with glaucoma surgery versus cataract surgery as a standalone procedure.
P < 0.0001 for a difference in endophthalmitis proportions between cataract surgery with anterior vitrectomy versus cataract surgery as a stand-alone procedure.
Visual Outcomes among Cataract Surgery Patients with and without Endophthalmitis
In aggregate, visual acuity improved from a median of approximately 20/50 (0.40 logMAR) before surgery to approximately 20/30 (0.18 logMAR) 3 months after cataract surgery (Table 3). Measured visual acuity declined slightly among patients without endophthalmitis between 1 and 3 months after surgery (median, 0.10 and 0.18 logMAR, respectively); however, fewer patients’ EHR reported visual acuity measurements at 3 months (n = 30 480) compared with 1 month (n = 51 852). Patients without endophthalmitis who continue to be followed up longer may disproportionately represent a population experiencing delayed recovery or other eye problems. Visual acuity among endophthalmitis patients continued to improve between 1 and 3 months after surgery (median, 0.80 and 0.40 logMAR, respectively).
Table 3.
Best-Corrected Visual Acuity Outcomes after Cataract Surgery with and without Endophthalmitis, 2013–2017
| All Cataract Surgeries | Cataract Surgeries with Endophthalmitis | Cataract Surgeries without Endophthalmitis | P Value* | |
|---|---|---|---|---|
| Visual acuity, mean (SD)† | ||||
| Before surgery‡ | 0.48 (0.48) | 0.61 (0.64) | 0.48 (0.48) | <0.0001 |
| 1 wk after surgery§ | 0.32 (0.46) | 1.45 (1.13) | 0.31 (0.46) | <0.0001 |
| 1 mo after surgery‖ | 0.25 (0.40) | 0.92 (0.79) | 0.25 (0.40) | <0.0001 |
| 3 mos after surgery¶ | 0.27 (0.42) | 0.71 (0.71) | 0.27 (0.42) | <0.0001 |
| Visual acuity, median† | ||||
| Before surgery‡ | 0.40 | 0.40 | 0.40 | |
| 1 wk after surgery§ | 0.18 | 1.05 | 0.18 | |
| 1 mo after surgery‖ | 0.10 | 0.80 | 0.10 | |
| 3 mos after surgery¶ | 0.18 | 0.40 | 0.18 | |
| 20/20 or better#, no. (%)** | ||||
| Before surgery‡ | 265 067 (5.49) | 129 (3.74) | 264 938 (5.49) | <0.0001 |
| 1 wk after surgery§ | 14 470 (25.02) | 7 (6.36) | 14 463 (25.06) | <0.0001 |
| 1 mo after surgery‖ | 16 250 (31.31) | 1 (2.17) | 16 249 (31.34) | <0.0001 |
| 3 mos after surgery¶ | 8229 (26.98) | 1 (4.00) | 8228 (26.99) | <0.0001 |
| <20/20–≥20/40††, no. (%)** | ||||
| Before surgery‡ | 2 001 372 (41.45) | 1243 (36.08) | 2 000 129 (41.45) | <0.0001 |
| 1 wk after surgery§ | 28 831 (49.86) | 16 (14.55) | 28 815 (49.92) | <0.0001 |
| 1 mo after surgery‖ | 24 699 (47.59) | 10 (21.74) | 24 689 (47.61) | <0.0001 |
| 3 mos after surgery¶ | 15 423 (50.56) | 10 (40.00) | 15 413 (50.57) | <0.0001 |
| <20/40–≥20/100‡‡, no. (%)** | ||||
| Before surgery‡ | 1 756 530 (36.38) | 1240 (35.99) | 1 755 290 (36.38) | <0.0001 |
| 1 wk after surgery§ | 9361 (16.19) | 18 (16.36) | 9343 (16.19) | <0.0001 |
| 1 mo after surgery‖ | 7347 (14.16) | 12 (26.09) | 7335 (14.15) | <0.0001 |
| 3 mos after surgery¶ | 4571 (14.98) | 4 (16.00) | 4567 (14.98) | <0.0001 |
| <20/100–≥20/200§§, no. (%)** | ||||
| Before surgery‡ | 349 674 (7.24) | 293 (8.51) | 349 381 (7.24) | <0.0001 |
| 1 wk after surgery§ | 2168 (3.75) | 14 (12.73) | 2154 (3.73) | <0.0001 |
| 1 mo after surgery‖ | 1559 (3.00) | 10 (21.74) | 1549 (2.99) | <0.0001 |
| 3 mos after surgery¶ | 906 (2.97) | 3 (12.00) | 903 (2.96) | <0.0001 |
| Worse than 20/200‖‖, no. (%)** | ||||
| Before surgery‡ | 455 818 (9.44) | 540 (15.67) | 455 278 (9.44) | <0.0001 |
| 1 wk after surgery§ | 2998 (5.18) | 55 (50.00) | 2943 (5.10) | <0.0001 |
| 1 mo after surgery‖ | 2043 (3.94) | 13 (28.26) | 2030 (3.91) | <0.0001 |
| 3 mos after surgery¶ | 1376 (4.51) | 7 (28.00) | 1369 (4.49) | <0.0001 |
logMAR = logarithm of the minimum angle of resolution; SD = standard deviation.
P values calculated for a difference in means or proportions, respectively, between all cataract surgeries and cataract surgeries with endophthalmitis.
Measured in logarithm of the minimum angle of resolution.
Measured within 60 days before surgery until the day of surgery.
Measured within 3–15 days after surgery.
Measured within 16–42 days after surgery.
Measured within 43–120 days after surgery.
≤0 logMAR.
Percentages calculated based on all surgeries seen at a given period (e.g., the percent of cataract surgeries with 20/20 or better vision at the preoperative visit occurring closest to the date of surgery).
0 < logMAR ≤ 0.3.
0.3 < logMAR ≤ 0.7.
0.7 < logMAR ≤ 1.0.
>1.0 logMAR.
At 3 months after surgery, 22.46% of all cataract surgery patients showed worse than 20/40 (0.3 logMAR) visual acuity and 26.98% showed 20/20 (0 logMAR) visual acuity or better. Patients who experienced acute-onset endophthalmitis after cataract surgery overall achieved worse visual outcomes, with a median visual acuity of approximately 20/50 (0.40 logMAR) at 3 months after surgery. Four percent of endophthalmitis patients achieved 20/20 or better visual acuity and 56.00% of patients achieved worse than 20/40 visual acuity.
Discussion
Conditions such as endophthalmitis are difficult to study because of their rarity, and the current literature largely relies on analyses from high-volume centers. However, clinical data registries, including the IRIS Registry, have opened a new frontier in big data. The IRIS Registry enables evaluation of endophthalmitis at a hitherto unprecedented scale, including many more patients than other data sources such as Medicare claims data and other third-party claims databases, and broadly encompassing clinical care provided by ophthalmologists across multiple insurance plans around the country. In this study, IRIS Registry data on more than 5 million patients who underwent cataract surgery between 2013 and 2017 were used to measure the incidence of acute-onset postoperative endophthalmitis, assess visual outcomes, and evaluate differences when cataract surgery is combined with other ocular procedures.
This analysis identified 4 key findings. First, 0.04% of 8 542 838 patients who underwent cataract surgery performed in the United States between 2013 and 2017 were diagnosed with presumed acute-onset endophthalmitis within 30 days of surgery. Second, the highest rates of endophthalmitis were present in patients younger than 45 years, particularly among patients younger than 18 years. Third, endophthalmitis rates were substantially higher among patients undergoing cataract surgery combined with other ocular procedures, and patients who underwent cataract surgery with anterior vitrectomy showed the highest incidence of endophthalmitis (0.35%). Finally, despite lower average postoperative visual outcomes, 4% of endophthalmitis patients still achieved visual acuity of 20/20 or better at 3 months, and 44% achieved visual acuity of 20/40 or better.
Reported rates of acute-onset endophthalmitis occurring after cataract surgery vary, ranging from 0.02% to 0.2%.5–22 These findings, which build on an initial IRIS Registry-based analysis presented by Coleman26 for the 2015 American Academy of Ophthalmology Jackson Memorial Lecture, suggest an endophthalmitis incidence of 0.05% in a large cohort of United States cataract surgery patients. These results are most similar to those of a recent study of comprehensive public and private administrative claims in France from 2005 through 2014. Despite an overall incidence of 0.10% over the study period, they found that the annual incidence rate had declined to 0.05% by 2014, comparable with the current analysis of IRIS Registry data from 2013 through 2017. However, unlike the French analysis, which identified lower incidence of endophthalmitis after combined cataract and glaucoma surgery (compared with cataract surgery alone), this IRIS Registry analysis indicated a higher incidence of acute-onset endophthalmitis within 30 days after combined glaucoma cases. This makes intuitive sense, because incisional glaucoma procedures provide an entry pathway for infectious pathogens and independently carry a long-term risk of endophthalmitis.
Prior United States-based national studies of large patient populations have primarily relied on Medicare claims,5,6,9,17 for which the vast majority of patients are 65 years of age and older and are restricted to Medicare Fee-for-Service plans. Using IRIS Registry data allows inclusion of a broader population of patients, including those of younger ages, drawing from Medicaid, commercial health care plans, health insurance exchanges, and self-pay as well as Medicare and Medicare Advantage plans. Prior studies have suggested higher rates among younger patients as well as the very old.12,19,27 Findings in this current study suggest that the difference in younger patients could be substantial. The proportional representation of patients 0 to 17 years of age was more than fivefold higher among those with acute-onset endophthalmitis compared with all patients undergoing cataract surgery (1.04% vs. 0.20%), and similarly, patients 18 to 44 years of age represented a more than twofold higher proportion of endophthalmitis cases versus all cataract surgeries (5.53% vs. 2.27%). It is unusual to perform surgery in this age group; patients younger than 45 years represented less than 1% of all cataract surgery patients. Younger patients undergoing surgery may be more prone to touch their eyes in the postoperative period. They are also likely to have other ocular comorbidities or prior surgery or trauma (e.g., prior pars plana vitrectomy, ruptured globe with lens capsule compromise, glaucoma, corneal disease, and uveitis or inflammation), which lead to a higher risk of surgical complications and are not adjusted for in this analysis. Analogously, the highest incidence of endophthalmitis was observed in this sample among patients who underwent anterior vitrectomy, and vitreous loss is an acknowledged risk factor for acute endophthalmitis.11,15
Unlike other studies, it is also worth noting that this analysis found the incidence of acute-onset endophthalmitis in the very old to be similar to that in younger patients. Those 85 years of age and older were found to show a comparable incidence of endophthalmitis as those 45 to 64 years of age (0.05% over 5 years of data), and the absolute incidence was only slightly higher than that among patients 65 to 84 years of age (0.04%). This is an important potential finding that warrants further study because it goes against the conventional wisdom that poor wound healing or impaired immune surveillance in the very old leads to a higher rate of endophthalmitis.9,12,17,19,28 Because of the large scale of IRIS Registry data, this analysis is unique for its sizeable cohort of cataract surgery patients older than 85 years (802 717 patients).
Few large-scale studies exist to help predict final visual recovery after acute-onset endophthalmitis. Based on the existing literature, most patients end up with vision worse than 20/40 and many with 20/200 vision or worse. However, some may still recover excellent vision. Based on IRIS Registry data, endophthalmitis patients’ visual acuity at 3 months after surgery was 20/100 on average, but the median visual acuity was better (20/50), almost half of patients (44%) achieved driving-level vision of 20/40 or better, and 4% of patients achieved vision of 20/20 or better. These outcomes suggest a possible bimodal distribution of visual outcomes.
This large-scale analysis of acute-onset endophthalmitis after cataract surgery is relevant to quality-of-care efforts. Results provide pertinent and timely information to share with patients as well as a national benchmark for practice improvement. Currently, practices are able to view their performance in quality measures via the IRIS Registry practice dashboard, which can be expanded over time with addition of other metrics that practices desire to track. Aggregate data allow performance monitoring and policy interventions to improve access to care and quality over time. The findings presented in this analysis are relevant to 2 Merit-Based Incentive Payment System quality measures currently in effect: 192 (complications requiring reoperation within 30 days after surgery) and 191 (20/40 or better best-corrected visual acuity within 90 days after surgery). Knowledge of national trends will help ophthalmologists better target their own performance rates and further enhance outcomes of their patients.
This study is limited by several factors, including potential errors in EHR documentation, missing data, and use of code-based data in the IRIS Registry (with inherent coding imprecision or inaccuracies). However, although subject to some of the same limitations as administrative claims data, the IRIS Registry is preferred because it includes basic clinical information. The results do not include additional clinical details such as surgical technique (phacoemulsification vs. manual small-incisional cataract surgery or large-incision manual extracapsular cataract surgery), incision type (clear corneal vs. scleral tunnel), suture placement, sutured IOL, intracameral antibiotic use, or other antibiotics that are used or prescribed in the perioperative period but not noted in the ambulatory EHR. Additionally, the IRIS Registry is retrospective and observational; real-world clinical data and documentation may not be subject to the same rigorous validation as clinical trial data. For example, endophthalmitis cases were identified by a diagnosis indicating clinical signs of endophthalmitis; presumably these include some cases that were nonmicrobial and purely inflammatory, especially in children. However, despite limitations, the IRIS Registry carries distinct advantages for an analysis such as this. Direct extraction of clinical information from the EHR with little burden on participating clinicians and practices enables seamless capture of longitudinal data on large numbers of patients at a scale that would not be feasible through other means. The IRIS Registry contains data on patients treated at practices across the nation, encompassing all insurance plans and ages, including those younger than 45 years, a group found to have the highest incidence of endophthalmitis in this analysis. This is the best comprehensive real-world data that can realistically be expected, and the feasibility of a clinical trial for endophthalmitis occurring after cataract surgery is a challenge because of the high cost and need for large sample sizes.
In conclusion, this analysis of more than 5 million IRIS Registry patients indicates an acute-onset endophthalmitis incidence of 0.04% after cataract surgery based on data from 2013 through 2017 that captures real-world practice among United States ophthalmologists. Similar to prior studies, a higher incidence was found among patients undergoing cataract surgery combined with other ocular surgeries, among those who underwent anterior vitrectomy, and among patients younger than 45 years. Importantly, visual acuity outcomes seem to vary, with many patients ending up legally blind; nevertheless, patients can recover excellent vision after surgery (44% achieving driving-level vision of 20/40 or better). This is valuable information for counseling patients. However, the full potential of IRIS Registry data to evaluate endophthalmitis occurring after cataract surgery remains to be tapped, including longer-term investigation of trends over time, adjusted regression analyses, and incorporation of additional clinical and surgical details such as surgical technique and the use of intracameral antibiotics.
Supplementary Material
Supplemental material available at www.aaojournal.org.
Acknowledgments
Supported by the National Institutes of Health, Bethesda, Maryland (grant nos.: R03AG056453 [S.P.] and P30EY10572 [M.F.C.]); and Research to Prevent Blindness, Inc., New York, New York (Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon [M.F.C.] and Byers Eye Institute, Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, California [S.P.]). The IRIS Registry is owned by the American Academy of Ophthalmology, San Francisco, California. The funding organizations has no role in the design or conduct of this research.
Abbreviations and Acronyms:
- EHR
electronic health record
- IRIS
Intelligent Research in Sight
- logMAR
logarithm of the minimum angle of resolution
Footnotes
Presented in part at: American Society of Cataract and Refractive Surgery Annual Meeting, Los Angeles, California, May 2017.
Financial Disclosure(s):
The author(s) have made the following disclosure(s): S.P.: Consultant – Acumen LLC (Burlingame, CA); Equity owner – Verana Health (San Francisco, CA).
F.L.: Employee – American Academy of Ophthalmology (San Francisco, CA).
S.H.: Employee – American Academy of Ophthalmology (San Francisco, CA).
S.K.: Employee – American Academy of Ophthalmology (San Francisco, CA).
W.L.R.: Consultant – American Academy of Ophthalmology (San Francisco, CA).
M.F.C.: Advisory board – Clarity Medical Systems (Pleasanton, CA); Consultant – Novartis (Basel, Switzerland); Financial support – Genentech; Equity owner – Inteleretina (Honolulu, HI); Patent – Artificial intelligence system for retinopathy of prematurity diagnosis
D.W.P.: Employee – American Academy of Ophthalmology (San Francisco, CA)
HUMAN SUBJECTS: This study used human subjects data. The Institutional Review Boards approved the study and waived the requirement for informed consent because of the retrospective nature of the study. All research adhered to the tenets of the Declaration of Helsinki.
No animal subjects were included in this study.
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