Incidence of Non-arteritic Anterior Ischemic Optic Neuropathy after Cataract Surgery: A Systematic Review and Meta-Analysis

Authors: Arnav Gupta, Tushar Tejpal, Rahul A. Sharma.
Author Disclosure Block: A. Gupta: None. T. Tejpal: None. R.A. Sharma: None.

Purpose: To determine by systematic review and meta-analysis the outcomes, risk factors, and incidence of post-operative non-arteritic anterior ischemic optic neuropathy (NAION) following cataract surgery (pcsNAION). 

Study Design: Systematic Review with Meta-Analysis 

Methods: A systematic literature search of PubMed, MEDLINE, and EMBASE was performed in May 2021 with no limits set on the date of publication. Observational studies were included. Quality and bias were assessed using critical appraisal tools from the Joanna Briggs Institute. A random-effects meta-analysis was performed to compare the incidence of spontaneous and pcsNAION at 6 months following cataract extraction. All studies were assessed by two independent reviewers Results: A total of 1938 NAION patients from 19 studies were included. Topical anesthesia (73%, n = 130/178) was the most common method of anesthesia used; cataract extraction most often occurred via phacoemulsification with clear corneal incision (56.3%, n = 107/190). A meta-analysis of two studies comparing incidence of spontaneous and pcsNAION at 6 months among patients undergoing cataract surgery revealed an OR of 4.76 [95% CI 2.21, 10.27] (p < 0.0001). Systemic risk factors (i.e., age, prior comorbidities) and ocular parameters (i.e. cup-to-disc ratio) did not statistically differ between pcsNAION and sNAION patients. 

Conclusions: Based on the results of our meta-analysis, cataract surgery does appears to represent a significant risk factor for the occurrence of NAION. Within the first 6 months post-operatively, patients who underwent cataract surgery were more likely to develop NAION compared to unoperated counterparts. This association was noted particularly in cases where retrobulbar anesthesia was used. While the underlying pathophysiology remains unestablished, pcsNAION may occur due to vascular insufficiency induced by subclinical inflammation, which may result from surgical factors including pre-operative anesthesia, ocular manipulation, and perioperative procedures. A greater understanding of the pathogenesis responsible for pcsNAION will enable the development of prophylactic strategies to minimize post-operative risk. Future studies will benefit from larger sample size, randomized studies with standardized demographics and outcome documentation with outcomes stratified by various perioperative factors.