Abstract
Purpose:
To evaluate visual acuity (VA) outcomes and complications from resident physician-performed cataract surgery in a diverse Veterans Affairs Hospital population.
Methods:
A retrospective chart review was conducted for patients who underwent cataract surgery performed by resident physicians from 01/01/2013 to 12/31/2015 at the Veterans Affairs Medical Center. Intraoperative and postoperative clinical information, best-corrected VA (BCVA) (1 day, months 1, 2-3, and 6), and surgery complications were extracted. Univariable and multivariable linear regression models were performed for risk factors of BCVA change.
Results:
This study included 1183 patients, with mean (SD) age of 70.8 (9.3) years. 1154 (97.5%) were males, 493 (41.7%) African-American, and 681 (57.6%) Caucasian. The mean (SD) VA in logMAR was 0.69 (0.74) at baseline, improved to 0.19 (0.36) at 1 month, 0.16 (0.34) at 2-3 months, and 0.14 (0.36) at 6 months. 1080 (91.3%) patients experienced VA improvement from baseline and 1023 (86.5%) patients achieved at least 20/40 BCVA at 1 month. There were 86 (7.3%) complications, most commonly including 47 (4.0%) posterior capsular tears and 64 (5.4%) vitreous loss. In multivariable analysis, younger age (P < 0.0001), worse baseline VA (P < 0.0001), and absence of iris prolapse (P < 0.001) were significantly associated with greater improvement in VA at 1 month.
Conclusion:
In a diverse VAMC, resident-performed cataract surgeries achieved significant improvement in VA with a cumulative complication rate lower than previously reported. Resident physician education may benefit from specific focus on prevention of iris prolapse and better incision construction during surgery as these intraoperative events often led to delayed stabilization of visual outcome beyond 1 month.
Keywords: Cataract surgery, cataract surgery complication rates, resident-performed surgery, Veterans Affairs Medical Center, visual outcomes
Cataract surgery is one of the most commonly performed surgical procedures across the globe, with growing demand as society ages. Therefore, training resident physicians to perform cataract surgery and ensuring quality of care delivery are a particularly important part of an ophthalmology residency program. Furthermore, the increasing emphasis on outcome-based approaches to resident physician education over simple minimum requirements drives the need for evaluation of resident physician-performed procedures.[1] Although there are many studies examining the complications and outcomes of resident physician-performed cataract surgery,[2-12] they are difficult to apply to individual institutions due to the wide range of patient populations and comorbidities, resident physician curriculums, surgical volumes, and due to different phacoemulsification technologies (more ECCE cases) and residency training structures in older studies (1984-1997).[2-12,10] A more recent study analyzed 1290 resident physician-performed cataract surgeries;[13] however, the authors focused on visual outcomes and complication rates at a tertiary-care county hospital as compared to other training hospitals and did not find significant predictors for complications or poor visual outcomes.
Studies focusing on the Veterans Health Administration (VHA) are impactful given the high volume and frequency of cases with resident physicians as primary surgeons. A multi-institutional study across five VHA medical centers involving 4,221 cases evaluated multiple intraoperative and postoperative factors and found that resident physician-operated cases with and without intraoperative complications had an overall significant improvement in (VA) and visual function.[3] However, follow-up time and demographic diversity were limited, necessitating further study of resident physician-operated cataract surgery outcomes.[12,14]
Beyond residency-specific training, there have been few studies examining objective functional visual outcomes of cataract surgery at a large range of preoperative best-corrected visual acuity (BCVA). Therefore, in this study, we hope to expand on previous studies examining resident physician-performed cataract surgeries to determine visual outcomes, surgery complications, and to identify preoperative risk factors for poor visual outcomes in a diverse population.
Methods
A retrospective chart review was conducted for patients who underwent resident physician-performed phacoemulsification cataract surgery at the Veterans Affairs Medical Center from 01/01/2013 to 12/31/2015. This three-year time period allowed us to assess 15-20 resident physicians as the primary surgeons without including any current resident physicians that would be identifiable. Demographics and information regarding the surgery and outcomes over 6 months after cataract surgery were gathered including previous medical and ocular histories, baseline exam, cataract classification, medication usage, and prior ocular surgery. Intraoperative data were extracted including date, type of cataract surgery, presence of concurrent glaucoma surgery, length of surgery, use of trypan blue, iris hooks, malyugin ring, and capsular tension ring or sutures, as well as surgical complications including hyphema, choroidal effusion, retrobulbar hematoma, dropped nucleus, iris prolapse, anterior capsule tear, posterior capsule tear, zonular dehiscence, and vitreous loss. Data from the complete follow-up examinations and medication use at 1 day, 1 week, 1 month, 2-3 months, and 6 months were collected. Patients were excluded if they did not return for follow-up after surgery. The study was approved by the Veterans Association Institutional Review Board.
Of note, patients were not preselected in any way for residents. Instead, the service was considered to be “resident run,” meaning that all cataract cases that present will be completed with the resident as the primary surgeon. In addition, all residents were senior pgy4 residents in the last six months of their residency training.
Statistical analysis
Descriptive statistics were calculated using mean (standard deviation [SD]) for normally distributed data, median (1st quartile, 3rd quartile), minimum and maximum for skewed data, and using frequency and percentage for categorical characteristics and cataract surgery complications. Mean VA change from baseline in logMAR was calculated for 1 day, 1 week, 1 month, 2-3 months, and 6 months postsurgery and were tested for their statistically significant change from baseline using paired t-tests. Univariable and multivariable linear regression models were performed to determine the risk factors for a VA change from baseline and worsening VA at 1 month after cataract surgery. To improve the statistical power, we also evaluated the factors associated with VA change from baseline at week 1, month 1, 2-3, and 6 combined, by using the generalized linear regression model that accounted for both the intereye correlation from patients who contributed data from both eyes and correlations from repeated measures from the same eye. In these analyses, risk factors with P value < 0.10 in univariable analysis were included in the initial multivariable model, and backward variable selection was used to derive the final multivariable models. All statistical analyses were performed in SAS version 9.4 (SAS Institute Inc., Cary, NC), and 2-sided P values < 0.05 were considered statistically significant.
Results
Characteristics of patients
The study included 1183 patients, with mean (SD) age of 70.8 (9.3) years. 1154 (97.5%) of patients were males, 493 (41.7%) African-American, and 681 (57.6%) Caucasian [Table 1]. Preoperative VA had a median (interquartile range) of 0.4 (0.3, 0.7) logMAR (Snellen: Median 20/50, interquartile 20/100 to 20/40), ranging from 20/25 to count finger. Furthermore, demographics and systemic comorbidities are shown in Table 1. In terms of cataract type and grade, 1140 (96.6%) were noted to have nuclear sclerosis (NS), 710 (59.7%) cortical spokes (CS), and 629 (52.9%) posterior subcapsular cataracts (PSC) with further characterization in Table 1. Duration of surgery was on average 51.2 minutes (standard deviation 49.7 minutes) [Table 1] and was not significantly associated with grade of cataract, complication rate, or visual acuity outcomes [Supplementary Tables 1-3].
Table 1.
Preoperational characteristics (n=1183)
| Preoperational Characteristics | n (%) |
|---|---|
| Age (years): Mean (SD) | 70.8 (9.3) |
| Race | |
| Asian | 4 (0.3%) |
| Black | 493 (41.7%) |
| White | 681 (57.6%) |
| Other | 5 (0.4%) |
| Gender | |
| Female | 29 (2.5%) |
| Male | 1154 (97.5%) |
| Visual acuity (logMAR): Median (1st quartile, 3rd quartile) | 0.4 (0.3, 0.7) |
| Baseline IOP in mmHg: Mean (SD) | 14.8 (3.5) |
| Nuclear sclerosis | |
| 0 | 40 (3.4%) |
| 0.5 | 8 (0.7%) |
| 1 | 181 (15.3%) |
| 2 | 545 (46.2%) |
| 3 | 357 (30.3%) |
| 4 | 49 (4.2%) |
| Cortical spokes | |
| 0 | 473 (40.3%) |
| 0.5 | 48 (4.1%) |
| 1 | 230 (19.6%) |
| 2 | 273 (23.2%) |
| 3 | 123 (10.5%) |
| 4 | 28 (2.4%) |
| Posterior subcapsular cataract | |
| 0 | 554 (47.1%) |
| 0.5 | 70 (6.0%) |
| 1 | 196 (16.7%) |
| 2 | 173 (14.7%) |
| 3 | 139 (11.8%) |
| 4 | 43 (3.7%) |
| Cup to disc ratio: Mean (D) | 0.4 (0.2) |
| Number of glaucoma medications: Mean (SD) | 0.1 (0.3) |
| Number of glaucoma drops: Mean (SD) | 0.1 (0.5) |
| Alpha blocker | 338 (28.6%) |
| Medical history | |
| Ocular trauma | 103 (8.7%) |
| Diabetes | 643 (54.4%) |
| Hypertension | 929 (78.5%) |
| Retinal surgery | 25 (2.1%) |
| Glaucoma surgery | 15 (1.3%) |
| Corneal surgery | 2 (0.2%) |
| Refractive surgery | 2 (0.2%) |
| Uveitis | 3 (0.3%) |
Supplementary Table 1.
Univariate analysis for association between baseline and intra-operational characteristics and change in VA at month 1 and association between baseline and intra-operational characteristics and change in VA (longitudinal analysis including visits at week 1, month 1, month 2-3 and month 6
| Patient characteristics | Univariable | Univariable | ||||
|---|---|---|---|---|---|---|
|
|
|
|||||
| # of subjects at month 1 (n=1034) n | Change in VA at month 1 (from baseline) | # of subjects (n=1183) n | Mean change in VA at week 1, month 1, month 2-3 and month 6 (from baseline) | |||
|
|
|
|||||
| Mean (SE) | P | Mean (SE) | P | |||
| Age (years) | 0.01 (0.00) | <0.0001 | 0.01 (0.00) | <0.0001 | ||
| Race | 0.27 | 0.001 | ||||
| Black | 432 | -0.51 (0.03) | 493 | -0.60 (0.04) | ||
| White | 596 | -0.45 (0.03) | 681 | -0.47 (0.02) | ||
| Other | 6 | -0.27 (0.29) | 9 | -0.10 (0.13) | ||
| Gender | 0.75 | 0.91 | ||||
| Female | 27 | -0.43 (0.14) | 29 | -0.54 (0.12) | ||
| Male | 1007 | -0.47 (0.02) | 1154 | -0.52 (0.02) | ||
| Laterality | 0.29 | 0.14 | ||||
| OD | 532 | -0.50 (0.03) | 603 | -0.55 (0.03) | ||
| OS | 502 | -0.45 (0.03) | 580 | -0.49 (0.03) | ||
| Baseline visual acuity (logMAR) | -0.89 (0.02) | <0.0001 | -0.90 (0.02) | <0.0001 | ||
| Baseline IOP | 0.01 (0.01) | 0.22 | 0.01 (0.01) | 0.12 | ||
| Nuclear sclerosis | <0.0001 | <0.0001 | ||||
| 0 | 35 | -0.82 (0.12) | 40 | -0.87 (0.17) | ||
| 0.5 | 8 | -0.87 (0.24) | 8 | -0.88 (0.37) | ||
| 1 | 155 | -0.42 (0.06) | 181 | -0.49 (0.05) | ||
| 2 | 466 | -0.35 (0.03) | 545 | -0.39 (0.02) | ||
| 3 | 325 | -0.52 (0.04) | 357 | -0.57 (0.04) | ||
| 4 | 42 | -1.28 (0.11) | 49 | -1.44 (0.16) | ||
| Cortical spokes | 0.03 | 0.12 | ||||
| 0 | 412 | -0.52 (0.03) | 473 | -0.57 (0.04) | ||
| 0.5 | 44 | -0.28 (0.11) | 48 | -0.37 (0.08) | ||
| 1 | 196 | -0.45 (0.05) | 230 | -0.48 (0.04) | ||
| 2 | 236 | -0.43 (0.05) | 273 | -0.49 (0.04) | ||
| 3 | 113 | -0.43 (0.07) | 123 | -0.48 (0.06) | ||
| 4 | 25 | -0.80 (0.14) | 28 | -0.82 (0.18) | ||
| Posterior subcapsular cataract | <0.0001 | <0.0001 | ||||
| 0 | 493 | -0.46 (0.03) | 554 | -0.51 (0.03) | ||
| 0.5 | 68 | -0.33 (0.09) | 70 | -0.34 (0.05) | ||
| 1 | 163 | -0.39 (0.06) | 196 | -0.42 (0.04) | ||
| 2 | 150 | -0.40 (0.06) | 173 | -0.42 (0.05) | ||
| 3 | 119 | -0.67 (0.06) | 139 | -0.76 (0.06) | ||
| 4 | 33 | -0.96 (0.12) | 43 | -1.11 (0.14) | ||
| Cup to disc ratio | 0.01 (0.12) | 0.92 | -0.05 (0.12) | 0.67 | ||
| Number of glaucoma medications at baseline | 0.08 (0.07) | 0.25 | 0.10 (0.08) | 0.21 | ||
| Number of glaucoma medications at baseline | 0.47 | 0.33 | ||||
| 0 | 937 | -0.48 (0.02) | 1080 | -0.53 (0.02) | ||
| 1 | 93 | -0.41 (0.07) | 99 | -0.42 (0.07) | ||
| 2 | 4 | -0.16 (0.36) | 4 | -0.37 (0.77) | ||
| Number of glaucoma drops at baseline | 0.02 (0.04) | 0.64 | 0.03 (0.05) | 0.58 | ||
| Number of glaucoma drops at baseline | 0.86 | 0.54 | ||||
| 0 | 946 | -0.48 (0.02) | 1089 | -0.53 (0.02) | ||
| 1 | 36 | -0.43 (0.12) | 36 | -0.43 (0.12) | ||
| 2 | 35 | -0.38 (0.12) | 41 | -0.40 (0.10) | ||
| ≥3 | 17 | -0.47 (0.17) | 17 | -0.57 (0.26) | ||
| Alpha blocker | 0.21 | 0.03 | ||||
| No | 725 | -0.49 (0.03) | 845 | -0.55 (0.03) | ||
| Yes | 309 | -0.43 (0.04) | 338 | -0.45 (0.03) | ||
| History of ocular trauma | 0.64 | 0.66 | ||||
| No | 943 | -0.47 (0.02) | 1080 | -0.52 (0.02) | ||
| Yes | 91 | -0.51 (0.08) | 103 | -0.55 (0.07) | ||
| History of diabetes | 0.36 | 0.58 | ||||
| No | 461 | -0.45 (0.03) | 540 | -0.51 (0.03) | ||
| Yes | 573 | -0.49 (0.03) | 643 | -0.53 (0.03) | ||
| History of hypertension | 0.34 | 0.55 | ||||
| No | 214 | -0.43 (0.05) | 254 | -0.50 (0.04) | ||
| Yes | 820 | -0.48 (0.03) | 929 | -0.53 (0.02) | ||
| History of retinal surgery | 0.29 | 0.21 | ||||
| No | 1012 | -0.47 (0.02) | 1158 | -0.52 (0.02) | ||
| Yes | 22 | -0.63 (0.15) | 25 | -0.76 (0.19) | ||
| History of glaucoma surgery | 0.99 | 0.91 | ||||
| No | 1019 | -0.47 (0.02) | 1168 | -0.52 (0.02) | ||
| Yes | 15 | -0.47 (0.18) | 15 | -0.50 (0.18) | ||
| History of corneal surgery | 0.79 | 0.22 | ||||
| No | 1032 | -0.47 (0.02) | 1181 | -0.52 (0.02) | ||
| Yes | 2 | -0.34 (0.51) | 2 | -0.36 (0.06) | ||
| History of refractive surgery | 0.64 | 0.17 | ||||
| No | 1032 | -0.47 (0.02) | 1181 | -0.52 (0.02) | ||
| Yes | 2 | -0.24 (0.51) | 2 | -0.19 (0.06) | ||
| Glaucoma surgery done at the same time | 0.03 | 0.001 | ||||
| No | 1007 | -0.48 (0.02) | 1155 | -0.53 (0.02) | ||
| Yes | 27 | -0.18 (0.14) | 28 | -0.26 (0.06) | ||
| Length of surgery (per 100 min increase) | 0.03 (0.04) | 0.52 | 0.01 (0.03) | 0.6 | ||
| Length of surgery (min) | 0.22 | 0.12 | ||||
| ≤34 | 270 | -0.47 (0.04) | 317 | -0.48 (0.03) | ||
| >34 and ≤43 | 254 | -0.53 (0.04) | 290 | -0.59 (0.04) | ||
| >43 and ≤60 | 256 | -0.40 (0.04) | 293 | -0.48 (0.04) | ||
| >60 | 254 | -0.49 (0.04) | 283 | -0.54 (0.05) | ||
| Retrobulbar hematoma | 0.95 | 0.32 | ||||
| No | 1033 | -0.47 (0.02) | 1182 | -0.52 (0.02) | ||
| Yes | 1 | -0.43 (0.72) | 1 | -0.35 (0.00) | ||
| Trypan blue | <0.0001 | <0.0001 | ||||
| No | 987 | -0.44 (0.02) | 1123 | -0.49 (0.02) | ||
| Yes | 47 | -1.07 (0.10) | 60 | -1.23 (0.15) | ||
| Iris hook | 0.03 | 0.07 | ||||
| No | 629 | -0.43 (0.03) | 751 | -0.49 (0.03) | ||
| Yes | 405 | -0.53 (0.04) | 432 | -0.57 (0.04) | ||
| Malyugin ring | 0.12 | 0.35 | ||||
| No | 583 | -0.44 (0.03) | 685 | -0.50 (0.03) | ||
| Yes | 451 | -0.51 (0.03) | 498 | -0.55 (0.04) | ||
| Capsular tension ring | 0.28 | 0.14 | ||||
| No | 1011 | -0.48 (0.02) | 1159 | -0.53 (0.02) | ||
| Yes | 23 | -0.31 (0.15) | 24 | -0.32 (0.13) | ||
| Suture | 0.17 | 0.7 | ||||
| No | 696 | -0.49 (0.03) | 807 | -0.53 (0.02) | ||
| Yes | 338 | -0.43 (0.04) | 376 | -0.51 (0.04) | ||
| Hyphema | 0.62 | 0.74 | ||||
| No | 1030 | -0.47 (0.02) | 1179 | -0.52 (0.02) | ||
| Yes | 4 | -0.65 (0.36) | 4 | -0.40 (0.35) | ||
| Dropped nucleus | 0.2 | 0.49 | ||||
| No | 1016 | -0.48 (0.02) | 1162 | -0.53 (0.02) | ||
| Yes | 18 | -0.26 (0.17) | 21 | -0.34 (0.26) | ||
| Iris prolapse | 0.02 | 0.14 | ||||
| No | 1027 | -0.48 (0.02) | 1173 | -0.53 (0.02) | ||
| Yes | 7 | 0.17 (0.27) | 10 | -0.07 (0.28) | ||
| Anterior capsule tear | 0.96 | 0.66 | ||||
| No | 1028 | -0.47 (0.02) | 1176 | -0.52 (0.02) | ||
| Yes | 6 | -0.49 (0.29) | 7 | -0.39 (0.30) | ||
| Posterior capsule tear | 0.33 | 0.57 | ||||
| No | 993 | -0.48 (0.02) | 1136 | -0.53 (0.02) | ||
| Yes | 41 | -0.37 (0.11) | 47 | -0.43 (0.17) | ||
| Zonular dehiscence | 0.96 | 0.81 | ||||
| No | 1022 | -0.47 (0.02) | 1170 | -0.52 (0.02) | ||
| Yes | 12 | -0.48 (0.21) | 13 | -0.47 (0.23) | ||
| Vitreous loss | 0.18 | 0.45 | ||||
| No | 979 | -0.48 (0.02) | 1119 | -0.53 (0.02) | ||
| Yes | 55 | -0.35 (0.10) | 64 | -0.42 (0.13) | ||
| Uveitis | 0.54 | 0.13 | ||||
| No | 1031 | -0.47 (0.02) | 1180 | -0.52 (0.02) | ||
| Yes | 3 | -0.22 (0.41) | 3 | -0.17 (0.11) | ||
Supplementary Table 3.
Univariable analysis for association of baseline and intra-operational characteristics with VA worsening at month 1 (among eyes with POAG or Narrow Angle Glaucoma)
| Patient characteristics | n=169, n | VA worsening n (%) | Univariable | |
|---|---|---|---|---|
|
| ||||
| OR (95%CI) | P | |||
| Age (years) | 1.05 (1.00-1.11) | 0.051 | ||
| Race | 0.67 | |||
| Black | 114 | 15 (13.2%) | 1.24 (0.47-3.65) | |
| White | 55 | 6 (10.9%) | Ref. | |
| Gender | - | |||
| Female | 2 | 0 (0.0%) | Ref. | |
| Male | 167 | 21 (12.6%) | - | |
| Laterality | 0.0495 | |||
| OD | 90 | 7 (7.8%) | Ref. | |
| OS | 79 | 14 (17.7%) | 2.55 (1.00-7.08) | |
| Baseline visual acuity (logMAR) | 0.31 (0.06-0.87) | 0.02 | ||
| Baseline IOP | 1.04 (0.94-1.14) | 0.44 | ||
| Nuclear sclerosis* | 0.58 | |||
| 0 | 7 | 1 (14.3%) | Ref. | |
| 0.5 | 2 | 0 (0.0%) | - | |
| 1 | 20 | 1 (5.0%) | 0.32 (0.32-0.32) | |
| 2 | 76 | 12 (15.8%) | 1.13 (1.13-1.13) | |
| 3 | 58 | 7 (12.1%) | 0.82 (0.82-0.82) | |
| 4 | 4 | 0 (0.0%) | - | |
| Cortical spokes* | 0.39 | |||
| 0 | 69 | 8 (11.6%) | Ref. | |
| 0.5 | 5 | 1 (20.0%) | 1.91 (0.19-19.24) | |
| 1 | 28 | 0 (0.0%) | - | |
| 2 | 43 | 10 (23.3%) | 2.31 (0.83-6.42) | |
| 3 | 18 | 2 (11.1%) | 0.95 (0.18-4.94) | |
| 4 | 4 | 0 (0.0%) | - | |
| Posterior subcapsular cataract | 0.25 | |||
| 0 | 85 | 14 (16.5%) | Ref. | |
| 1 | 25 | 3 (12.0%) | 0.69 (0.15-2.36) | |
| 2 | 26 | 1 (3.8%) | 0.20 (0.01-1.09) | |
| 3 | 21 | 1 (4.8%) | 0.25 (0.01-1.38) | |
| 0.5 | 10 | 2 (20.0%) | 1.27 (0.18-5.75) | |
| Cup to disc ratio | 2.01 (0.25-17.78) | 0.52 | ||
| Number of glaucoma medications at baseline | 2.94 (1.21-7.89) | 0.02 | ||
| Number of glaucoma medications at baseline | 0.048 | |||
| 0 | 72 | 4 (5.6%) | Ref. | |
| 1 | 93 | 16 (17.2%) | 3.53 (1.23-12.79) | |
| 2 | 4 | 1 (25.0%) | 5.67 (0.25-58.27) | |
| Number of glaucoma drops at baseline | 1.40 (0.92-2.11) | 0.11 | ||
| Number of glaucoma drops at baseline | 0.09 | |||
| 0 | 81 | 5 (6.2%) | Ref. | |
| 1 | 36 | 7 (19.4%) | 3.67 (1.09-13.28) | |
| 2 | 35 | 7 (20.0%) | 3.80 (1.12-13.78) | |
| ≥3 | 17 | 2 (11.8%) | 2.03 (0.27-10.42) | |
| Alpha blocker | 0.59 | |||
| No | 129 | 17 (13.2%) | Ref. | |
| Yes | 40 | 4 (10.0%) | 0.73 (0.20-2.13) | |
| History of ocular trauma | 0.50 | |||
| No | 155 | 20 (12.9%) | Ref. | |
| Yes | 14 | 1 (7.1%) | 0.52 (0.03-2.83) | |
| History of diabetes | 0.23 | |||
| No | 76 | 12 (15.8%) | Ref. | |
| Yes | 93 | 9 (9.7%) | 0.57 (0.22-1.43) | |
| History of hypertension | 0.63 | |||
| No | 26 | 4 (15.4%) | Ref. | |
| Yes | 143 | 17 (11.9%) | 0.74 (0.25-2.76) | |
| History of retinal surgery | - | |||
| No | 167 | 21 (12.6%) | Ref. | |
| Yes | 2 | 0 (0.0%) | - | |
| History of glaucoma surgery | 0.57 | |||
| No | 156 | 20 (12.8%) | Ref. | |
| Yes | 13 | 1 (7.7%) | 0.57 (0.03-3.12) | |
| History of corneal surgery | ||||
| No | 169 | 21 (12.4%) | Ref. | |
| History of refractive surgery | ||||
| No | 169 | 21 (12.4%) | Ref. | |
| Glaucoma surgery done at the same time | 0.12 | |||
| No | 142 | 15 (10.6%) | Ref. | |
| Yes | 27 | 6 (22.2%) | 2.42 (0.79-6.72) | |
| Length of surgery (per 100 min increase) | 0.63 (0.35-0.85) | 0.38 | ||
| Length of surgery (min) | 0.36 | |||
| ≤34 | 29 | 3 (10.3%) | Ref. | |
| >34 and≤43 | 37 | 2 (5.4%) | 0.50 (0.06-3.19) | |
| >43 and≤60 | 37 | 5 (13.5%) | 1.35 (0.30-7.10) | |
| >60 | 66 | 11 (16.7%) | 1.73 (0.49-8.14) | |
| Retrobulbar hematoma | ||||
| No | 169 | 21 (12.4%) | Ref. | |
| Trypan blue | - | |||
| No | 157 | 21 (13.4%) | Ref. | |
| Yes | 12 | 0 (0.0%) | - | |
| Iris hook | 0.35 | |||
| No | 97 | 14 (14.4%) | Ref. | |
| Yes | 72 | 7 (9.7%) | 0.64 (0.23-1.63) | |
| Malyugin ring | 0.054 | |||
| No | 88 | 15 (17.0%) | Ref. | |
| Yes | 81 | 6 (7.4%) | 0.39 (0.13-1.01) | |
| Capsular tension ring | - | |||
| No | 166 | 21 (12.7%) | Ref. | |
| Yes | 3 | 0 (0.0%) | - | |
| Suture | 0.01 | |||
| No | 106 | 8 (7.5%) | Ref. | |
| Yes | 63 | 13 (20.6%) | 3.18 (1.26-8.53) | |
| Hyphema | ||||
| No | 169 | 21 (12.4%) | Ref. | |
| Dropped nucleus | 0.03 | |||
| No | 166 | 19 (11.4%) | Ref. | |
| Yes | 3 | 2 (66.7%) | 15.47 (1.42-342.2) | |
| Iris prolapse | - | |||
| No | 168 | 20 (11.9%) | Ref. | |
| Yes | 1 | 1 (100.0%) | - | |
| Anterior capsule tear | ||||
| No | 169 | 21 (12.4%) | Ref. | |
| Posterior capsule tear | 0.24 | |||
| No | 162 | 19 (11.7%) | Ref. | |
| Yes | 7 | 2 (28.6%) | 3.01 (0.41-15.09) | |
| Zonular dehiscence | - | |||
| No | 167 | 21 (12.6%) | Ref. | |
| Yes | 2 | 0 (0.0%) | - | |
| Vitreous loss | 0.48 | |||
| No | 159 | 19 (11.9%) | Ref. | |
| Yes | 10 | 2 (20.0%) | 1.84 (0.27-8.05) | |
| Uveitis | - | |||
| No | 167 | 21 (12.6%) | Ref. | |
| Yes | 2 | 0 (0.0%) | - | |
*Multivariable model initially included variables with P<0.1 (except Dropped nucleus) and used backward selection to get the final model. *Records with category of 0% or 100% incidence were excluded from the univariable analysis
When considering intraoperative characteristics. 28 (2.4%) had glaucoma surgery performed at the time of cataract surgery [Table 2]. In cataract surgery, 60 (5.1%) used trypan blue, 432 (36.5%) used iris hooks, 498 (42.1%) used a malyugin ring, 24 (2.0%) used a capsular tension ring, and 376 (31.8%) used a suture.
Table 2.
Intraoperative characteristics and complications (n=1183)
| Intraoperative characteristics | Statistics |
|---|---|
| Glaucoma surgery done at the same time | 28 (2.4%) |
| Length of surgery (min): Mean (SD) | 51.2 (49.7) |
| Retrobulbar hematoma | 1 (0.1%) |
| Trypan blue | 60 (5.1%) |
| Iris hooks | 432 (36.5%) |
| Malyugin ring | 498 (42.1%) |
| Capsular tension ring | 24 (2.0%) |
| Suture | 376 (31.8%) |
| Complications | |
| Hyphema | 4 (0.3%) |
| Choroidal effusion | 0 (0%) |
| Dropped nucleus | 21 (1.8%) |
| Iris prolapse | 10 (0.8%) |
| Anterior capsule tear | 7 (0.6%) |
| Posterior capsule tear | 47 (4.0%) |
| Zonular dehiscence | 13 (1.1%) |
| Vitreous loss | 64 (5.4%) |
Complications of cataract surgery
Intraoperative complications of cataract surgery occurred in 86 (7.3%) patients, including hyphema (n = 4, 0.3%) patients, dropped nucleus (n = 2, 1.8%) in patients, iris prolapse (n = 10, 0.8%) patients, anterior capsular tears (n = 7, 0.6%) in patients, posterior capsular tears (n = 47, 4.0%) in patients, zonular dehiscence (n = 13, 1.1%) in patients, and vitreous loss (n = 64, 5.4%) in patients [Table 2]. Eleven patients (0.9%) required a revision or repeat surgery within 30 days for complications including dropped nucleus, retained nuclear fragment, dislocated intraocular lens, wound leak, uncontrolled elevation in IOP, and retinal detachment.
Visual acuity outcome
After cataract surgery, patients showed the greatest VA improvement from baseline by week 1 (logMAR 0.69 at baseline, 0.19 at week 1). VA was relatively stable from week 1 to month 6 [Table 3]. Grouping by baseline VA demonstrated that patients with baseline logMAR 0.3 (20/40) or better did not experience a significant improvement in VA from baseline [Table 3]. In contrast, patients with baseline logMAR 0.3 to 0.5 or 0.5-1.0, and >1.0 experienced significant improvement in VA from baseline, with worse preoperative VA associated with a greater improvement from baseline [Table 3].
Table 3.
Change of visual acuity after surgery overall and segmented by baseline operative visual acuity
| Visual acuity outcome# of eyes at baseline | Time | All subjects n=1183 | Baseline Visual Acuity logMAR Group | ||||
|---|---|---|---|---|---|---|---|
|
| |||||||
| ≤0.3 n=116 | >0.3–≤0.5 n=616 | >0.5–≤1.0 n=307 | >1.0 n=144 | P* | |||
| Mean visual acuity in logMAR (SD) | Baseline | 0.69 (0.74) | 0.13 (0.08) | 0.37 (0.07) | 0.72 (0.17) | 2.45 (0.76) | - |
| Day 1 | 0.47 (0.59) | 0.35 (0.05) | 0.40 (0.02) | 0.51 (0.03) | 0.83 (0.05) | <0.0001 | |
| Week 1 | 0.20 (0.39) | 0.16 (0.04) | 0.14 (0.02) | 0.26 (0.02) | 0.39 (0.03) | <0.0001 | |
| Month 1 | 0.19 (0.36) | 0.14 (0.03) | 0.12 (0.01) | 0.25 (0.02) | 0.41 (0.03) | <0.0001 | |
| Month 2-3 | 0.16 (0.34) | 0.15 (0.04) | 0.10 (0.02) | 0.19 (0.02) | 0.37 (0.03) | <0.0001 | |
| Month 6 | 0.14 (0.36) | 0.13 (0.05) | 0.09 (0.02) | 0.20 (0.03) | 0.30 (0.05) | <0.0001 | |
| Mean visual acuity change from baseline in logMAR (SD) | Day 1 | -0.22 (0.84) | 0.22 (0.06) | 0.02 (0.03) | -0.22 (0.04) | -1.62 (0.05) | <0.001 |
| Week 1 | -0.49 (0.76) | 0.04 (0.04) | -0.24 (0.02) | -0.47 (0.03) | -2.05 (0.04) | <0.001 | |
| Month1 | -0.47 (0.72) | 0.02 (0.04) | -0.25 (0.02) | -0.47 (0.03) | -1.98 (0.04) | <0.001 | |
| Month 2-3 | -0.51 (0.70) | 0.02 (0.05) | -0.27 (0.02) | -0.53 (0.03) | -2.01 (0.04) | <0.001 | |
| Month 6 | -0.49 (0.68) | 0.00 (0.06) | -0.29 (0.02) | -0.52 (0.04) | -2.00 (0.06) | <0.001 | |
*For test of any difference in mean visual acuity or mean visual acuity change from baseline across baseline visual acuity groups. **There was subject attrition over the course of the study time period such that n=1171 on day 1, 1166 on week 1, 1034 on month 1, 867 on months 2-3, and 600 on month 6
Given that VA remained stable after week 1 in this population [Table 3], univariate [Supplementary Table 1] and multivariate [Table 4] risk factor analysis for VA change from baseline at 1 month was performed. In multivariable analysis, younger age (P < 0.0001), worse baseline VA (P < 0.0001), and absence of iris prolapse (P < 0.001) were significantly associated with greater VA improvement from baseline [Table 4]. In longitudinal analysis combining all VA measures at 1 week and after, younger age (P < 0.0001) and worse baseline VA (P < 0.0001) remained significantly associated with greater VA improvement from baseline.
Table 4.
Multivariable analysis for factors association with visual acuity change from baseline at month 1 VA change from baseline at all follow-up visits
| Characteristics | VA Change from baseline at month 1 | VA Change from baseline at week 1, months 1, 2-3, and 6 | ||
|---|---|---|---|---|
|
|
|
|||
| Adjusted Mean (SE) | P | Adjustment Mean (SE) | P | |
| Age (years) | 0.01 (0.00) | <0.0001 | 0.01 (0.00) | <0.0001 |
| Baseline visual acuity (logMAR) | -0.88 (0.02) | <0.0001 | -0.89 (0.02) | <0.0001 |
| Iris prolapse | <0.001 | |||
| No (n=1027) | -0.48 (0.01) | |||
| Yes (n=7) | 0.03 (0.13) | |||
Analysis for factors associated with any worsening in VA postoperatively was also performed through univariable analysis [Supplementary Table 2] and multivariable analysis [Table 5] stratified by the baseline preoperative glaucoma status. In multivariate analysis among patients without baseline glaucoma, worse baseline VA (OR = 0.04, P < .0001) and higher baseline IOP (OR = 0.48, p. 02) were associated with lower risk of worsening VA. Vitreous loss was significantly associated with higher risk of worsened VA after surgery (OR = 13.5, P < 0.0001). When considering patients with glaucoma, older age (OR = 0.52, P = 0.02) and worse baseline VA (OR = 0.21, P = 0.01) were found to be associated lower risk of worsening VA postoperatively, whereas suture use was associated with a significantly higher risk of VA worsening postoperatively (OR = 3.53, P = 0.01) [Table 5, Supplementary Table 3].
Supplementary Table 2.
Univariable analysis for association of baseline and intra-operational characteristics with VA worsening at month 1 (among eyes without POAG or Narrow Angle Glaucoma)
| Patient characteristics | n=865, n | VA worsening n (%) | Univariable | |
|---|---|---|---|---|
|
| ||||
| OR (95%CI) | P | |||
| Age (years) | 1.03 (1.01-1.06) | 0.02 | ||
| Race* | 0.81 | |||
| Black | 318 | 21 (6.6%) | 0.94 (0.94-0.94) | |
| White | 541 | 38 (7.0%) | Ref. | |
| Other | 6 | 0 (0.0%) | - | |
| Gender | 0.54 | |||
| Female | 25 | 1 (4.0%) | Ref. | |
| Male | 840 | 58 (6.9%) | 1.78 (0.37-32.08) | |
| Laterality | 0.56 | |||
| OD | 442 | 28 (6.3%) | Ref. | |
| OS | 423 | 31 (7.3%) | 1.17 (0.69-1.99) | |
| Baseline visual acuity (logMAR) | 0.06 (0.01-0.22) | <0.0001 | ||
| Baseline IOP | 0.92 (0.85-1.00) | 0.052 | ||
| Nuclear sclerosis | 0.88 | |||
| 0 | 28 | 3 (10.7%) | Ref. | |
| 0.5 | 6 | 1 (16.7%) | 1.67 (0.07-16.53) | |
| 1 | 135 | 8 (5.9%) | 0.52 (0.14-2.52) | |
| 2 | 390 | 28 (7.2%) | 0.64 (0.21-2.82) | |
| 3 | 267 | 17 (6.4%) | 0.57 (0.17-2.54) | |
| 4 | 38 | 2 (5.3%) | 0.46 (0.06-2.99) | |
| Cortical spokes | 0.67 | |||
| 0 | 343 | 20 (5.8%) | Ref. | |
| 0.5 | 39 | 1 (2.6%) | 0.43 (0.02-2.13) | |
| 1 | 168 | 14 (8.3%) | 1.47 (0.71-2.96) | |
| 2 | 193 | 14 (7.3%) | 1.26 (0.61-2.54) | |
| 3 | 95 | 8 (8.4%) | 1.49 (0.60-3.37) | |
| 4 | 21 | 2 (9.5%) | 1.70 (0.26-6.44) | |
| Posterior subcapsular cataract | 0.38 | |||
| 0 | 408 | 28 (6.9%) | Ref. | |
| 0.5 | 58 | 1 (1.7%) | 0.24 (0.01-1.15) | |
| 1 | 138 | 12 (8.7%) | 1.29 (0.62-2.56) | |
| 2 | 124 | 11 (8.9%) | 1.32 (0.61-2.67) | |
| 3 | 98 | 5 (5.1%) | 0.73 (0.24-1.79) | |
| 4 | 33 | 2 (6.1%) | 0.88 (0.14-3.11) | |
| Cup to disc ratio | 2.61 (0.51-12.30) | 0.25 | ||
| Alpha blocker | 0.44 | |||
| No | 596 | 38 (6.4%) | Ref. | |
| Yes | 269 | 21 (7.8%) | 1.24 (0.70-2.14) | |
| History of ocular trauma | 0.08 | |||
| No | 788 | 57 (7.2%) | Ref. | |
| Yes | 77 | 2 (2.6%) | 0.34 (0.06-1.13) | |
| History of diabetes | 0.94 | |||
| No | 385 | 26 (6.8%) | Ref. | |
| Yes | 480 | 33 (6.9%) | 1.02 (0.60-1.75) | |
| History of hypertension | 0.31 | |||
| No | 188 | 16 (8.5%) | Ref. | |
| Yes | 677 | 43 (6.4%) | 0.73 (0.41-1.36) | |
| History of retinal surgery | 0.73 | |||
| No | 845 | 58 (6.9%) | Ref. | |
| Yes | 20 | 1 (5.0%) | 0.71 (0.04-3.54) | |
| History of glaucoma surgery | - | |||
| No | 863 | 59 (6.8%) | Ref. | |
| Yes | 2 | 0 (0.0%) | - | |
| History of corneal surgery | - | |||
| No | 863 | 59 (6.8%) | Ref. | |
| Yes | 2 | 0 (0.0%) | - | |
| History of refractive surgery | - | |||
| No | 863 | 59 (6.8%) | Ref. | |
| Yes | 2 | 0 (0.0%) | - | |
| Length of surgery (per 100 min increase) | 0.54 (0.48-0.61) | 0.27 | ||
| Length of surgery (min) | 0.009 | |||
| ≤34 | 241 | 8 (3.3%) | Ref. | |
| >34 and ≤43 | 217 | 14 (6.5%) | 2.01 (0.84-5.12) | |
| >43 and ≤60 | 219 | 15 (6.8%) | 2.14 (0.91-5.42) | |
| >60 | 188 | 22 (11.7%) | 3.86 (1.74-9.43) | |
| Retrobulbar hematoma | - | |||
| No | 864 | 59 (6.8%) | Ref. | |
| Yes | 1 | 0 (0.0%) | - | |
| Trypan blue | 0.29 | |||
| No | 830 | 58 (7.0%) | Ref. | |
| Yes | 35 | 1 (2.9%) | 0.39 (0.02-1.87) | |
| Iris hooks | 0.30 | |||
| No | 532 | 40 (7.5%) | Ref. | |
| Yes | 333 | 19 (5.7%) | 0.74 (0.42-1.29) | |
| Malyugin ring | 0.31 | |||
| No | 495 | 30 (6.1%) | Ref. | |
| Yes | 370 | 29 (7.8%) | 1.32 (0.77-2.24) | |
| Capsular tension ring | 0.20 | |||
| No | 845 | 56 (6.6%) | Ref. | |
| Yes | 20 | 3 (15.0%) | 2.49 (0.57-7.68) | |
| Suture | 0.23 | |||
| No | 590 | 36 (6.1%) | Ref. | |
| Yes | 275 | 23 (8.4%) | 1.40 (0.81-2.40) | |
| Hyphema | 0.25 | |||
| No | 861 | 58 (6.7%) | Ref. | |
| Yes | 4 | 1 (25.0%) | 4.61 (0.23-36.67) | |
| Dropped nucleus | 0.37 | |||
| No | 850 | 57 (6.7%) | Ref. | |
| Yes | 15 | 2 (13.3%) | 2.14 (0.33-8.00) | |
| Iris prolapse | 0.41 | |||
| No | 859 | 58 (6.8%) | Ref. | |
| Yes | 6 | 1 (16.7%) | 2.76 (0.14-17.50) | |
| Anterior capsule tear | 0.054 | |||
| No | 859 | 57 (6.6%) | Ref. | |
| Yes | 6 | 2 (33.3%) | 7.04 (0.96-36.84) | |
| Posterior capsule tear | <0.0001 | |||
| No | 831 | 49 (5.9%) | Ref. | |
| Yes | 34 | 10 (29.4%) | 6.65 (2.90-14.34) | |
| Zonular dehiscence | 0.17 | |||
| No | 855 | 57 (6.7%) | Ref. | |
| Yes | 10 | 2 (20.0%) | 3.50 (0.52-14.37) | |
| Vitreous loss | <0.0001 | |||
| No | 820 | 46 (5.6%) | Ref. | |
| Yes | 45 | 13 (28.9%) | 6.84 (3.27-13.67) | |
| Uveitis | - | |||
| No | 864 | 59 (6.8%) | Ref. | |
| Yes | 1 | 0 (0.0%) | - | |
*Records with category of 0% or 100% incidence were excluded from the univariable analysis. *Multivariable model initially included variables with P<0.1 and used backward selection to get the final model
Table 5.
Multivariable analysis for factors association with VA worsening* at 1 month among eyes with and without POAG or narrow angle glaucoma**
| Patient characteristics | VA worsening at 1 month in patients without glaucoma (n=865) | VA worsening at 1 month in patients with glaucoma (n=169) | ||||
|---|---|---|---|---|---|---|
|
|
|
|||||
| VA worsening (%) | OR (95%CI) | P | VA worsening (%) | OR (95%CI) | P | |
| Age (years) | 0.52 (0.50-0.53) | 0.02 | ||||
| Baseline visual acuity (per logMAR increase) | 0.04 (0.01-0.15) | <0.0001 | 0.21 (0.06-0.52) | 0.01 | ||
| Baseline IOP (per 1 mmHg increase) | 0.48 (0.45-0.50) | 0.02 | ||||
| Vitreous loss | <0.0001 | |||||
| No | 46 (5.6%) | Reference | ||||
| Yes | 13 (28.9%) | 13.5 (5.8-31.1) | ||||
| Suture | 0.23 | 0.01 | ||||
| No | 36 (6.1%) | Reference | 8 (7.5%) | Reference | ||
| Yes | 23 (8.4%) | 1.40 (0.81-2.40) | 13 (20.6%) | 3.53 (1.31-9.52) | ||
*VA worsening was defined as a visual acuity at clinical presentation that was worse than their preoperative baseline visual acuity. **The definition of glaucoma for this analysis was a preoperative clinical diagnosis of primary open angle glaucoma (e.g., glaucomatous VF defect and/or IOP >=22 mmHg and/or CDR >.7, etc.) or narrow angle glaucoma (IOP >=22 and/or glaucomatous VF defect and/or CDR >.7 and narrow angles on gonioscopy)
In addition, statistically significant IOP elevations were observed on day 1 in glaucomatous eyes compared to eyes without glaucoma (2.81 vs. 0.12 mmHg, P < 0.0001); however, there were no statistically significant differences in IOP changes between glaucomatous and nonglaucomatous eyes at week 1 or after [Supplementary Table 4].
Supplementary Table 4.
Intraocular pressure and its change after surgery overall and segmented by baseline glaucoma status
| IOP Outcome | Time # of eyes at baseline | Baseline Glaucoma Status | P* | ||
|---|---|---|---|---|---|
|
|
|
||||
| All subjects (n=1175) | With Glaucoma (n=185) | Without Glaucoma (n=990) | |||
| Mean IOP in mmHg (SD) | Baseline | 14.80 (3.45) | 15.38 (4.36) | 14.69 (3.24) | 0.04 |
| Day 1 | 15.37 (5.66) | 18.20 (7.33) | 14.83 (5.12) | <0.0001 | |
| Week 1 | 14.42 (4.36) | 15.16 (4.89) | 14.28 (4.24) | 0.02 | |
| Month 1 | 13.36 (3.48) | 13.87 (4.31) | 13.26 (3.28) | 0.08 | |
| Month 2-3 | 12.92 (2.83) | 13.44 (3.26) | 12.81 (2.71) | 0.03 | |
| Month 6 | 12.63 (2.82) | 13.06 (3.30) | 12.54 (2.69) | 0.12 | |
| Mean change in IOP (mmHg) from baseline (SD) | Day 1 | 0.55 (5.92) | 2.81 (7.63) | 0.12 (5.44) | <0.0001 |
| Week 1 | -0.37 (4.76) | -0.19 (5.81) | -0.40 (4.55) | 0.65 | |
| Month1 | -1.44 (4.38) | -1.62 (5.66) | -1.40 (4.08) | 0.64 | |
| Month 2-3 | -1.91 (4.08) | -2.03 (4.87) | -1.88 (3.89) | 0.72 | |
| Month 6 | -2.17 (4.20) | -2.40 (4.98) | -2.12 (4.00) | 0.59 | |
History of diabetes, hypertension, retinal surgery, glaucoma surgery, corneal surgery, or refractive surgery was not significantly associated with change in visual acuity (from baseline) or visual acuity worsening (from baseline) [Supplementary Tables 1-3]. The population was further segmented by those with POAG or narrow angle glaucoma, and similarly history of diabetes, hypertension, retinal surgery, glaucoma surgery, corneal surgery, or refractive surgery was not significantly associated with change in visual acuity (from baseline) or visual acuity worsening (from baseline) [Supplementary Tables 1-3].
Discussion
Building on previous studies examining resident physician-performed cataract surgeries, we sought to evaluate the VA outcome and surgical complication rate and to identify risk factors for poor visual outcomes in resident physician-performed cataract surgery in a diverse population. We found that VA improved by approximately 0.5 logMAR by 1 week, with 91% of showing BCVA improvement from baseline and 87% of patients achieving 20/40 or better at 1 month (replicated with 3- and 6-month data with fewer patients). We found younger age, worse baseline VA, and absence of iris prolapse intraoperatively were significantly associated with greater improvement in VA at 1 month. Complications from cataract surgery were minimal with an overall rate of 7% including hyphema, dropped nucleus, iris prolapse, anterior capsular tears, posterior capsular tears, zonular dehiscence, and vitreous loss.
With respect to demographics, this population is unique, with over 40% patients identifying as African-American, a population considered more likely to have cataracts and less likely to obtain cataract surgery.[15,16] This population was also predominantly male, and in the 8.7% of patients of ocular trauma in the eye with cataract surgery, a rate higher than previously reported in the literature. Although ocular trauma may predispose to earlier cataract development, it was not predictive of worst visual outcome post cataract surgery. Most patients had cataract classification consisting of NS 2+; however, there was still a higher percentage of CS and PSC patients than previously reported in the literature.[17] This population also had a higher level of comorbidities including diabetes (54.5%) and hypertension (78.5%) than in comparable published studies (DM type II prevalence 47%),[18-20] providing insight into the effects of comorbidities on resident physician performed cataract surgery. Lastly, although previous studies have examined resident physician-performed cataract surgery at a variety of levels, to our knowledge, this is the largest population of patients treated entirely by senior third-year resident physicians prior to becoming attending surgeons and therefore were more likely to be more experienced with less complications.[13]
In this study, the mean VA improved significantly after surgery (with mean improvement of approximately 0.5 logMAR by 1 week), and only minimal complications (0.6% anterior capsule tears, 1.1% zonular dehiscence, and 0.9% requiring a revision or repeat surgery within 30 days), relatively low for a “training population,” and expected given the higher level of training of these resident physicians. As expected in the literature, posterior capsule tears and vitrectomy were relatively uncommon (4% and 5.4%, respectively) and were treated according to standard of care (anterior vitrectomy) in most cases.[21] Overall, 86.5% of patients achieved visual outcome BCVA of 20/40, comparable to the rates of 74% to 97.8% in the literature.[4-8] Predictive factors for postoperative VA included baseline VA (worse preop VA predicted more improvement in VA), which is likely a factor of how advanced their cataracts were to begin with. In addition, trypan blue was also associated with a greater improvement from baseline, likely related to the fact that very dense nuclear cataracts or 3+ or more cortical cataracts are the indications for using trypan blue needed to visualize the anterior capsule in these dense cataracts. These denser cataracts were correlated with the greatest improvement of VA postoperatively. A lack of intraoperative iris prolapse was found to be significantly associated with improvement in VA. The reason for this is not known, however, iris prolapse has been thought to traumatize the iris, leading to increased postoperative inflammation, transillumination defects, iris distortion, and pupillary abnormalities which may decrease the quality of vision and/or patient’s level of satisfaction.[22] In addition, after iris prolapse, attending surgeons are more likely to instruct residents to suture the wounds, which could have led to temporary suture induced astigmatism. This is further suggested by the improvement in vision in the iris prolapse patients after 1-month post-op suture removal. In considering ways of preventing iris prolapse, it is also important to consider whether the risk can be mitigated by encouraging more frequent use of malyugin ring.
Surprisingly, anterior capsule tear, posterior capsule tear, zonular dehiscence, and vitreous loss were not significantly associated with lessening of postoperative VA, which may be explained by effective intraoperative management of the complications. The rate of intraoperative and postoperative complications was lower than published in the literature (0-19.7%) [Table 6].[2-12,13] In other studies of hospital systems, vitreous loss was commonly reported ranging from 3.8% to 11.2%, with the rate of vitreous loss at this training hospital on the lower end (5.4%).[23] The prevalence of cystoid macular edema (CME) and corneal edema in our study also falls below previously reported ranges (0.56% to 4.6% and 0.6% to 8.1%, respectively) [Table 6].[2,3] However, it is important to note that this ignores any contribution of racial or ethnic demographics or cataract types.[13] Furthermore, this study also demonstrated a high rate (~30-40%) of intraoperative device use of iris hooks, malyugin ring, and suture, speaking to the characteristically challenging nature of cataracts in this population, with similar outcomes throughout.[13]
Table 6.
Intraoperative and postoperative complications of resident physician-performed cataract surgery in the literature
| Reference | Study Design Setting |
Intraoperative Complications | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||||||||
| Retrobulbar hematoma | Hyphema | Choroidal effusion | Dropped nucleus | Iris Prolapse | Anterior Capsule Tear | Posterior Capsule Tear | Zonular dehiscence | Vitreous Loss | ||||||||
| # Current Study | Veterans Affairs Medical Center (n=1183) | 0% | 0.20% | 0% | 1.80% | 0.80% | 0.60% | 4.00% | 1.10% | 5.40% | ||||||
| # Payal et al. 2016[3] | Veterans Affairs Ophthalmic Surgery Outcomes Database Project across 5 Veterans Affairs Medical Centers (n=4221) | -- | -- | 0.02% | 2.49% | 3.48% | 4.40% | 1.59% | 3.79% | |||||||
| # Briszi et al. 2012[2] | Tertiary care center (n=600) | -- | -- | -- | 1.16% | -- | -- | 3.80% | -- | 3.00% | ||||||
| # Corey and Olson 1998[4] | Urban, rural tertiary care academic center, and Veterans Affairs Medical Center (n=396) | -- | -- | -- | -- | -- | -- | 2.60% | -- | 1.80% | ||||||
| # Rogers et al. 2009[5] | Veterans Affairs Medical Center (n=320) | -- | -- | -- | -- | -- | -- | 7.17% | -- | 3.77% | ||||||
| # Allinson et al. 1992[8] | Tertiary care center (n=136) | -- | -- | -- | -- | -- | -- | -- | -- | 14.70% | ||||||
| # Tarbet et al. 1995[9] | Tertiary care center (n=300) | -- | -- | -- | -- | -- | -- | 3.30% | -- | 5.30% | ||||||
| # Smith and Seiff 1997[10] | Public county hospital (n=218) | -- | 0.40% | -- | 0.40% | -- | -- | 10% | -- | 6% | ||||||
| # Rutar et al. 2009[11] | Veterans Affairs Medical Center (n=320) | -- | -- | -- | 0.90% | -- | -- | 1.50% | -- | 3.10% | ||||||
| # Clarke et al. 2017[13] | Tertiary care center (n=1290) | -- | 0.50% | 0.10% | 0.60% | 1.20% | 4.0$ | 7.00% | 2.90% | 6.70% | ||||||
| # Blomquist et al. 2012[17] | Urban public county hospitals (n=2434) | -- | -- | -- | -- | -- | -- | -- | -- | 3.80% | ||||||
| # Gharaee et al. 2020[23] | Public county hospital in Iran (n=475) | -- | -- | -- | 0% | -- | 5.30% | 5.30% | 0.50% | 5.30% | ||||||
| ## Unal et al. 2006[24] | Tertiary care center (n=296) | -- | -- | -- | 2.70% | 0% | 5.30% | 2.60% | 0% | 6.10% | ||||||
|
| ||||||||||||||||
| #Design: Retrospective data analysis of deidentified data. ##Design: Prospective intervention (retrobulbar vs topical anesthesia) | ||||||||||||||||
|
| ||||||||||||||||
| Reference | Postoperative Complications | |||||||||||||||
|
| ||||||||||||||||
| Further surgery within 30 days | Endophthalmitis | Retinal detachment | CME | Choroidal hemorrhage | Retained nucleus | Hypopnea | Epithelial defect | |||||||||
|
| ||||||||||||||||
| # Current Study | 0.00% | 0.00% | 0.08% | 0.08% | 0.08% | 0.17% | 0.08% | 4.17% | ||||||||
| # Payal et al. 2016[3] | 0.64% | 0.16% | 0.26% | 2.44% | 0.02% | 2.39% | -- | 0.14% | ||||||||
| # Briszi et al. 2012[2] | -- | -- | -- | -- | -- | -- | -- | -- | ||||||||
| # Corey and Olson 1998[4] | -- | -- | -- | -- | -- | -- | -- | -- | ||||||||
| # Rogers et al. 2009[5] | -- | -- | -- | -- | -- | -- | -- | -- | ||||||||
| # Allinson et al. 1992[8] | -- | -- | -- | -- | -- | -- | -- | -- | ||||||||
| # Tarbet et al. 1995[9] | -- | -- | -- | -- | -- | -- | -- | -- | ||||||||
| # Smith and Seiff 1997[10] | -- | 0.40% | 0% | 4.60% | -- | -- | -- | -- | ||||||||
| # Rutar et al. 2009[11] | -- | -- | -- | -- | -- | -- | -- | -- | ||||||||
| # Clarke et al. 2017[13] | -- | 0.10% | 0.90% | 4.70% | -- | 1.90% | -- | 1.90% | ||||||||
| # Blomquist et al. 2012[17] | -- | -- | -- | -- | -- | -- | -- | -- | ||||||||
| # Gharaee et al. 2020[23] | -- | -- | -- | -- | -- | -- | -- | -- | ||||||||
| ## Unal et al. 2006[24] | -- | 0.67% | 0.30% | 4.60% | -- | -- | -- | -- | ||||||||
#Design: Retrospective data analysis of deidentified data. ##Design: Prospective intervention (retrobulbar vs topical anesthesia)
VA results stratified by levels of baseline VA were also illuminating. Although most patients did experience significant improvement in VA, individuals with a baseline VA of logMAR 0.3 (20/40) or better did not experience significant improvement in VA from baseline, possibly due to the ceiling effect of the maximum possible change in VA improvement. While recent studies have suggested that the widely accepted criterion for cataract surgery being worse than 20/40 may not apply to the American population,[16,25,26] this result further suggests that further evaluation of VA outcomes segmented by pre-op VA and type of cataract (cortical vs PSC) may be helpful to better optimizing timing of surgery and post-op vision. It is possible that patients in this resident physician training population may benefit from delaying cataract surgery until vision is 20/40 or worse.
Predictors for worsening VA, defined as VA at clinical presentation that was worse than preoperative baseline visual acuity, were also evaluated. Multivariable analysis demonstrated that among eyes without glaucoma, worse baseline VA was significantly associated with better postoperative VA. This was in line with our findings above, suggesting that patients are more likely to experience significant benefits from surgery with pre-op VA of worse than 20/40. Vitreous loss was associated with greater likelihood of VA worsening after surgery, suggesting that special attention should focus on decreasing the rate of this complication in resident physician-performed surgery. However, this may have been more a factor of the intraoperative challenges that led to vitrectomy. Higher IOP was also associated with decreased likelihood of VA worsening among eyes without glaucoma at baseline. Only older age and worse baseline VA was associated with lower risk of VA worsening postoperatively. The use of suture was significantly associated with higher risk of worsening VA at 1 month, likely because sutures are indicated when wound integrity may be questioned at the completion of surgery. Sutures that are left in can also cause astigmatism. A leak observed at the completion of surgery, necessitating suture placement, may be indicative of increased mechanical trauma intraoperatively with ensuing increased inflammation. Of note, after 1 month, worsening VA was not associated with use of suture, which further suggests that suture-induced astigmatism may have induced a temporarily worse acuity that would improve after suture removal.
It is important to note the main limitations of this retrospective study. First, the data collection is retrospective and therefore limited by resident physician documentation and potentially limited follow-up in the patient population, which may affect our assessment of VA outcome and complication rate. This extends to the operative record, and therefore, it is possible that the complication rate may be underestimated. Similarly, as this was a retrospective review of chart data, subject attrition over the course of the study limited the power of analyses at 6 months. Second, this review is limited in its ability to compare to the general population due to lack of literature on populations like the demographic at this site. Third, we focus on a resident physician population in their final 6 months of training; however, a subgroup analysis of residents in different years of training would be helpful in future studies to reflect the learning curve over the course of residency training. In addition, although this study focuses on resident physicians at similar levels of training, we could not evaluate outcomes by the duration of time on a particular rotation of residency training and therefore cannot address learning and improvement during the rotation on service, although all residents had very similar exposure (5-10 cases) to phacoemulsification cataract surgery prior to the start of this block based on the rotation structure of this particular residency program. Furthermore, surgical education is incredibly complex, and although these data allow for a discussion on certain steps of surgery such as the incision and complications such as iris prolapse, there are many important surgical issues and challenges that we do not discuss. For example, the capsulorrhexis, hydrodissection, challenging IOL implantations, and a plethora of technical details are a crucial component of resident physician education. However, in this study we are not able to speak to the impact of these key steps on surgical outcomes. Furthermore, our complication rate was very low, and therefore, we did not perform analysis for determining predictive risk factors for complication. Given the presence of an attending physician in each case, it is also possible that the intraoperative complications were mitigated by the presence of the attending; however, there are no available data on attending takeover for each of these cases limiting our ability to assess this effect. Additionally, this study focuses on cases utilizing phacoemulsification surgery, but does not examine ECCE or small incision cataract surgery (SICS). Therefore, future studies may benefit from comparing outcomes of resident performed ECCE, SICS, and phacoemulsification surgery as these techniques have a wide range of duration, exposure, and training during residency as well as types and incidence of complications. Finally, as this is a retrospective study, it was not possible to create a control group of surgeries performed by experienced surgeons in the same environment to further validate outcomes of surgeries performed by residents. In this population, residents were automatically designated as primary surgeons, and only in sparse cases of extremely complicated cataracts or patient request would an attending be designated as a primary surgeon, therefore even if the small cohort of attending performed surgeries was analyzed, these particular cases would not be comparable to those performed by residents. Future studies may benefit from further analysis directly comparing resident and attending performed outcomes in the same population. Future studies may also benefit from standardization protocols to corroborate preoperative VA with grade of cataract. Although the authors included history of diabetes, hypertension, retinal surgery, glaucoma surgery, corneal surgery, and refractive surgery to capture other etiologies for improvement or lack of improvement in VA after cataract surgery, it would be helpful for future studies to further delineate differences in outcomes, complications, and VA improvement after cataract surgery segmented by the presence of specific posterior segment, retinal, or macular pathologies (e.g. vitreous haze and retinal vessel abnormalities).
Conclusion
In conclusion, this study leverages a large cohort of resident physician-performed cataract surgery in a population with complex comorbidities and cataracts and extensive follow-up, suggesting that in this population, resident physician-performed surgeries achieve significant improvement in BCVA without a significantly greater complication rate than found in the literature.[3,23,27] This study demonstrated minimal complications, only slightly higher than nonresident-performed cataract surgery in the VHA population ranging from 1.1 to 3.6%.[28,29] Matching the consistency of surgical outcomes with patient safety is crucial to considering training paradigms. The results of this study further reinforce that resident-performed surgery can be beneficial to both patients and trainees without additional risk to patients. Resident physician education may benefit from specific focus on prevention of iris prolapse and better incision construction during the surgery as these intraoperative events often led to the need for suturing of the cataract incision and delaying the stability of the visual outcome until beyond 1 month.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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