A Population-Based Study of Anterior Ischemic Optic Neuropathy Following Cataract Surgery

Safety and prognosis of phacoemulsification using active sentry and active fluidics with different IOP settings - a randomized, controlled study

PURPOSE

To explore the impact of different intraoperative intraocular pressure (IOP) settings on the safety and prognosis in phacoemulsification.

METHODS

Age related cataract patients who met the inclusion criteria and underwent phacoemulsification by using active sentry handpiece and active fluidics system. According to different intraoperative IOP settings during surgery, they were randomly divided into two groups: the 20mmHg group and the 60mmHg group. The best corrected visual acuity (BCVA), cumulative dissipated energy (CDE), total U/S time, active surge mitigation (ASM), estimated fluid usage (EFU) as well as the changes in corneal thickness (CT), corneal epithelial layer thickness (CELT) and endothelial cell density (ECD) were collected. The post-operative follow-up was only 1 day.

RESULTS

A total of 110 cases (110 eyes) were included in the study. There were 55 eyes in each group. There was no statistically significant difference in postoperative BCVA (p = 0.839). The CDE, total U/S time and EFU during surgery were (5.22 ± 3.31), (30.60 ± 15.06), (45.07 ± 12.68) and (4.70 ± 2.83), (27.39 ± 13.75), (42.38 ± 11.93) in the 20mmHg group and 60mmHg group (p = 0.381, 0.246, 0.254). The ASM during surgery in the 20mmHg group and 60mmHg group were (0.95 ± 2.77) and (7.24 ± 6.34), respectively. The 20mmHg group showed a significant decrease in ASM (p < 0.001). There was no statistically significant difference in the changes in CT, CELT and ECD before and after surgery between the two groups (p = 0.913, 0.825, 0.624). Both groups did not experience any intraoperative complications, such as posterior capsule rupture.

CONCLUSION

A lower IOP setting of 20 mmHg can significantly reduce the occurrence of intraoperative surges during phacoemulsification. And there was no increase in rate of complications.

TRIAL REGISTRATION

The trial registration number is ChiCTR2100050240. The registered date is August 24th, 2021.

Nonarteritic Anterior Ischemic Optic Neuropathy After Cataract Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Nonarteritic anterior ischemic optic neuropathy (NAION) has been reported to occur after cataract surgery. It is not clearly established whether cataract surgery increases the risk of NAION over baseline.

EVIDENCE ACQUISITION

Medline, PubMed, Embase, and Cochrane Central registers were systematically searched for eligible studies reporting on postcataract surgery NAION (psNAION) within 1 year. All peer-reviewed publications with events n ≥ 10 were included. Pooled incidence and odds/hazard ratios and 95% confidence intervals (CIs) were extracted and calculated using random effect models for early and delayed psNAION. Time to event data were pooled for temporal analysis of psNAION events within the first year. This systematic review was registered (PROSPERO CRD42021274383).

RESULTS

Nine articles met the selection criteria with five studies suitable for meta-analysis. A total of 320 psNAION cases, 1,307 spontaneous NAION (sNAION) cases, 1,587,691 cataract surgeries, and 1,538,897 noncataract surgery controls were included. Pooling of 63,823 cataract surgeries and 161,643 controls showed a hazard ratio of 4.6 (95% CI 2.7-7.8) of psNAION within 1 year of surgery. Pooled unadjusted incidence of psNAION within 2 months was 99.92 (95% CI 38.64-161.19) per 100,000/year, psNAION within 1 year was 32.36 (95% CI 9.38-55.34) per 100,000/year, and sNAION was 8.87 (95% CI 2.12-15.62) per 100,000/year. psNAION cases were older by a mean of 7.6 years; otherwise, pooled odds ratios for baseline risk factors in psNAION vs. sNAION cases were not statistically significant. psNAION within the first year peaked within 72 hrs and at 6 weeks after the surgery with 73% of cases occurring within 6 months.

CONCLUSION

The risk of NAION after cataract surgery is four times greater within the first year and usually occurs within 6 months. However, the absolute risk remains low at 1 in 1,000-3,100 surgeries and is unlikely to warrant extra mention for consenting.

Application of the Active-Fluidics System in Phacoemulsification: A Review

The fluidics system is an indispensable and primary component of phacoemulsification. Both the gravity-fluidics system and active-fluidics system are commonly used in practice. The irrigation pressure of the gravity-fluidics system is determined by the bottle height, which is relatively constant, while the active-fluidics system is paired with a cassette that contains pressure sensors to monitor intraocular pressure changes. The active-fluidics system allows surgeons to preset a target intraocular pressure value, and it replenishes the fluids proactively; thus, the intraocular pressure is consistently maintained near the target value. Under such circumstances, stable intraocular pressure and anterior chamber volume values could be acquired. Research on surgical safety, efficiency and results have reported several strengths of the active-fluidics system. It is also advantageous in some complicated cataract surgeries. However, the system is not widely used at present, mainly due to its low penetration rate and high equipment cost. Some of its updates such as the new Active Sentry handpiece showed potential superiority in laboratory studies recently, but there is still further research to be conducted. This article gives an overview of the mechanism and performance of the active-fluidics system, and it is expected to provide clues for future research.

Post-cataract surgery optic neuropathy: a chronological narrative review of the literature and speculation on pathogenesis

PURPOSE OF REVIEW

To appraise the literature on the incidence of an acute anterior optic neuropathy resembling spontaneous nonarteritic anterior ischemic optic neuropathy (NAION) following uncomplicated cataract surgery and to explore the proposed pathogenesis of both immediate and delayed onset post-cataract surgery optic neuropathy (PCSON).

RECENT FINDINGS

A number of case reports, case series, and retrospective case-controlled, big data, and population-based studies have identified an apparent association between cataract surgery and the occurrence of an acute anterior optic neuropathy that can either be immediate or delayed in onset. However, a recent study found no link between modern day cataract surgery and an increased risk of an acute anterior optic neuropathy.

SUMMARY

Immediate PCSON appears to be related to negative perfusion pressure at the level of the optic disc due to increased intraocular pressure. The pathogenesis of delayed PCSON is unknown but probably multifactorial. Patients who have experienced spontaneous NAION or PCSON in one eye may be at risk of PCSON in the fellow eye.