Applying risk analysis to predict posterior capsule rupture during cataract surgery in New Zealand

Cataract surgery in Australia: a review of the regional literature and outcomes from 5018 cases at a tertiary teaching hospital

OBJECTIVES

To report visual and surgical outcomes of phacoemulsification cataract surgery from 5018 consecutive cases from Sydney, Australia. A review of the Australian and New Zealand literature was undertaken to provide a benchmark of outcomes from the region.

METHODS

The electronic medical record system was used to review three time-points for all phacoemulsification cataract surgeries at a tertiary-referral centre between May 2017 and August 2020: preoperative, intraoperative and one month postoperatively. Variables collected included uncorrected distance visual acuity (UDVA) and pinhole visual acuity, surgeon seniority and ocular pathology.

RESULTS

Of the 5018 eyes, 37.3% were operated on by consultants, 47.1% by trainees and 15.6% by fellows. Ocular pathology was seen in 48.9% of eyes (n=1709). The mean preoperative and one month postoperative UDVA was 6/48 and 6/12, respectively. There was an intraoperative complication in 7.6% of eyes (n=379) and posterior capsular rupture (PCR) occurred in 2.7% (n=136). PCR rates between consultants (3.1%, n=56), trainees (2.6%, n=61) and fellows (2.1%, n=16) showed no statistically significant difference (p≥0.355). The key risk factors for PCR were advanced cataract, alpha-antagonist use, small pupil size and the presence of glaucoma.

CONCLUSION

We present visual and surgical outcomes from the largest study on phacoemulsification cataract surgery in Australia and New Zealand, acknowledging the study's retrospective nature preventing inter-eye correlations, subdivision of cataract subspecialist versus not and trainee rank, and the minority of missing data. Our findings were comparable to regional and international benchmarks despite a high rate of ocular pathology and trainee case load. The lack of a regional cataract surgery registry represents a critical need in assessing and claiming key performance indicators, capturing emerging trends and identifying region-specific risk factors to deliver the best patient outcomes.

Application of Artificial Intelligence in the Analysis of Features Affecting Cataract Surgery Complications in a Teaching Hospital

Aims: To evaluate the ocular and systemic factors involved in cataract surgery complications in a teaching hospital using artificial intelligence. Methods: One eye of 1,229 patients with a mean age of 70.2 ± 10.3 years old that underwent cataract surgery was selected for this study. Ocular and systemic details of the patients were recorded and then analyzed by means of artificial intelligence. A total of 1.25 billion simulations of artificial intelligence learning and testing were conducted on several variables and a customized model of analysis was developed. Results: A total of 73 complications were recorded in this study. According to the analysis performed, the main factors involved in cataract surgery complications were: a surgeon in training, axial length and intraocular lens power. The model predicted how long surgery would last with an error of <6 min compared to the effective time needed. Conclusions: According to the data here obtained, artificial intelligence could be an interesting option to build customized models able to prevent complications and to predict actual surgery time. The customized algorithm option allows the development of better models adaptable to different units as well as the possibility to be calibrated for the same unit along time.

Contemporary Outcomes and Prognostic Factors of 23-Gauge Vitrectomy for Retained Lens Fragments After Phacoemulsification

PURPOSE

To provide data on visual acuity (VA) outcomes and prognostic factors of microincision (23-gauge) vitrectomy surgery (MIVS) for retained lens fragments after complicated cataract surgery.

DESIGN

Retrospective, interventional case series from 2012 to 2017.

METHODS

Precataract surgery and intraoperative (vitrectomy) parameters, postvitrectomy complications, and best-corrected visual acuities (BCVAs) were identified. Vitrectomy was performed as early as corneal clarity permitted. Univariate and multivariate logistic regression were used to characterize factors associated with achieving VA better than 20/40, or worse than 20/200 at 6 months.

RESULTS

This study included 291 consecutive eyes (291 patients). LogMAR BCVA improved from 0.73 ± 0.70 before cataract surgery to 0.46 ± 0.63 (P < .001) after vitrectomy. The previtrectomy VA was 1.43 ± 0.79. At 6 months, 183 (62.9%) and 45 patients (15.5%) achieved BCVAs better than 20/40 and worse than 20/200, respectively. Most frequent complications were de novo ocular hypertension (29 eyes, 10%) and transient cystoid macular edema (25 eyes, 8.6%). Postvitrectomy retinal detachment occurred in 9 eyes (3.1%). Final VA of 20/40 or better was independently associated only with better precataract surgery VA, age <75 years, absence of preexisting diabetic macular edema (DME) or postvitrectomy persistent cystoid macular edema (P < .05). Only poorer precataract surgery VA, delaying vitrectomy to later than 2 weeks, and final aphakic status were independently predictive of 20/200 or worse VA (P < .05).

CONCLUSION

Contemporary VA outcomes of 23-gauge vitrectomy for retained lens fragments are comparable with that of prior predominantly non-MIVS cohorts, but fall short of benchmarks for uncomplicated cataract surgery. IOL type or timing of placement do not impact final VA.

Auckland Cataract Study IV: Practical application of NZCRS cataract risk stratification to reduce phacoemulsification complications

IMPORTANCE

Reduction of intraoperative complications in phacoemulsification cataract surgery.

BACKGROUND

To assess practicability of a risk stratification system, the New Zealand Cataract Risk Stratification (NZCRS) system, in a major teaching hospital service, without investigator oversight, to ascertain whether benefits identified in research studies are maintained in busy clinical practice.

DESIGN

Prospective cohort study in a major public teaching hospital.

PARTICIPANTS

Five hundred cases of phacoemulsification cataract surgery.

METHODS

NZCRS system inserted into 621 consecutive preoperative cataract patient files. Recommendation to allocate higher-risk cases to experienced surgeons.

MAIN OUTCOME MEASURES

NZCRS system uptake and adherence, appropriate identification of high risk cases and intraoperative complication rates.

RESULTS

NZCRS scores calculated in 500 of 621 (80.5%) cases and 98 (19.6%) scored as "high risk." Cataract surgery (N = 500) performed by: 12 Registrars (20%), 4 Fellows (7.2%), 26 Consultants (72.8%). Risk scores adhered to in 99%. Overall intraoperative complications (3.0%) included iris prolapse 1.6% and posterior capsule tear 0.8%. No statistical difference in complication rates identified between surgeon grades. Mean best-corrected visual acuity was 6/10 (20/32). Postoperatively, cystoid macular oedema occurred in 3.2%. Rescoring by an experienced investigator noted a greater number of "high risk scores" (31.6% vs 19.6%) related to differences in subjective scoring of anterior chamber depth and cataract density.

CONCLUSIONS AND RELEVANCE

Practical uptake of cataract risk stratification was promising in this study with NZCRS calculated in 80.5% with 99% adherence to scoring recommendations. Compared to baseline studies, in the day-to-day clinical setting, a continued, decreasing trend in frequency and severity of intraoperative complications was noted. Subjective variability of risk scoring may be further improved by better, objective, standardization.

Auckland Cataract Study III: Refining Preoperative Assessment With Cataract Risk Stratification to Reduce Intraoperative Complications

PURPOSE

To assess intraoperative complications of phacoemulsification surgery in public teaching hospital settings using modified preoperative risk stratification systems.

DESIGN

Prospective cohort study.

METHODS

Preoperative risk stratification of 500 consecutive cataract cases using the New Zealand Cataract Risk Stratification (NZCRS) scoring system. Recommended allocation of higher-risk phacoemulsification procedures to experienced surgeons in public teaching hospital setting.

MAIN OUTCOME MEASURE

Intraoperative complications relative to adherence to stratification recommendations.

RESULTS

NZCRS classified 192 cases (38%) as high-risk, recommended for fellows or consultants (attendings). Primary surgeons were residents (n = 142, 28%), fellows (n = 88, 18%), and consultants (n = 270, 54%). Overall rate (N = 500) of any intraoperative complication was 5.0%. Where NZCRS scoring recommendations were observed (n = 448) the intraoperative complication rate was 4.5% but in "nonadherence" cases (n = 52 residents operating on higher-risk cases) this nearly doubled (9.6%). Postoperative complications occurred in 5.2%, primarily cystoid macular edema (3.7%). Postoperatively, mean unaided visual acuity was 6/12 (20/40) and best-corrected visual acuity improved from 6/20 (20/63) preoperatively to 6/10 (20/32) postoperatively (P < .05).

CONCLUSIONS

The NZCRS system aids identification of higher-risk cataract cases and appropriate case-to-surgeon allocation and may increase surgeon awareness of risk factors. Compared to 2 previous studies under similar conditions in the same institution, the NZCRS system was associated with a 40% reduction in intraoperative complications (8.4% to 5%). The rate of posterior capsular tear was 0.6% (P = .035) compared to 2.6% in baseline phase and 1.4% in a prior risk stratification phase. Risk stratification seems to reduce intraoperative phacoemulsification complications in public teaching hospital settings.

The Auckland Cataract Study II: Reducing Complications by Preoperative Risk Stratification and Case Allocation in a Teaching Hospital

PURPOSE

To assess the effect of preoperative risk stratification for phacoemulsification surgery on intraoperative complications in a teaching hospital.

DESIGN

Prospective cohort study.

METHODS

Prospective assessment of consecutive phacoemulsification cases (N = 500) enabled calculation of a risk score (M-score of 0-8) using a risk stratification system. M-scores of >3 were allocated to senior surgeons. All surgeries were performed in a public teaching hospital setting, Auckland, New Zealand, in early 2016. Postoperatively, data were reviewed for complications and corrected distance visual acuity (CDVA). Results were compared to a prospective study (N = 500, phase 1) performed prior to formal introduction of risk stratification.

RESULTS

Intraoperative complications increased with increasing M-scores (P = .044). Median M-score for complicated cases was higher (P = .022). Odds ratio (OR) for a complication increased 1.269 per unit increase in M-score (95% confidence interval [CI] 1.007-1.599, P = .043). Overall rate of any intraoperative complication was 5.0%. Intraoperative complication rates decreased from 8.4% to 5.0% (OR = 0.576, P = .043) comparing phase 1 and phase 2 (formal introduction of risk stratification). The severity of complications also reduced. A significant decrease in complications for M = 0 (ie, minimal risk cases) was also identified comparing the current study (3.1%) to phase 1 (7.2%), P = .034. There was no change in postoperative complication risks (OR 0.812, P = .434) or in mean postoperative CDVA (20/30, P = .484) comparing current with phase 1 outcomes.

CONCLUSION

A simple preoperative risk stratification system, based on standard patient information gathered at preoperative consultation, appears to reduce intraoperative complications and support safer surgical training by appropriate allocation of higher-risk cases.