Risk of Nonarteritic Anterior Ischemic Optic Neuropathy After Cataract Surgery

Non-arteritic anterior ischaemic optic neuropathy and obstructive sleep apnoea

Anterior ischaemic optic neuropathies (AIONs) are a common cause of permanent visual loss in the elderly population. The non-arteritic subtype has been intensively studied. While systemic associations such as hypertension and diabetes mellitus are commonly recognized and treated, others such as obstructive sleep apnoea (OSA) are largely overlooked in daily practice. A 60-year-old man who gave no history of any systemic illness presented to us 1 week following an uneventful cataract surgery with posterior chamber intraocular lens implantation in his right eye. The surgery was performed elsewhere by an eye-healthcare professional where the patient presented primarily with a history of progressively worsening diminution of vision in the same eye for 5 days and was diagnosed with a senile cataract. The postoperative visual gain was unsatisfactory; hence he sought another opinion. A diagnosis of non-arteritic AION (NAION) was established. Systemic evaluation revealed elevated diastolic blood pressure, dyslipidaemia and severe OSA. Prompt treatment with systemic steroids and simultaneous management of the accompanying systemic morbid conditions saved some useful vision in the affected eye. This also prevented involvement of the fellow unaffected eye. A comprehensive ocular examination with emphasis on systemic evaluation of the patient for coexisting illness is imperative before proceeding with any medical or surgical intervention. OSA is a definitive risk factor for the development of NAION, though it remains underdiagnosed and untreated. Cataract surgery has been shown to worsen underlying NAION. Systemic stabilization averts potentially blinding sequel in the unaffected eye of these patients.

Frequency and Etiologies of Visual Disturbance After Cataract Surgery Identified in Neuro-Ophthalmology Clinics

BACKGROUND

To identify the frequency and etiologies of visual disturbances after cataract surgery in patients referred to Neuro-ophthalmology.

METHODS

This study is a retrospective chart review. Records of patients 18 years and older referred to neuro-ophthalmology clinics for new-onset visual disturbances within 6 months of cataract surgery were reviewed. Those with pre-existing neuro-ophthalmic disorders, combined intraocular procedures with cataract surgery, or inadequate follow-up were excluded. The main outcome measures were frequency and etiologies of visual disturbances after cataract surgery. Secondary analyses of a cohort of patients who had cataract surgery at our institution were performed to determine the frequency and etiology of visual disturbances after uneventful cataract surgery.

RESULTS

One hundred seventy-three patients met the inclusion criteria (internal referral: 36/173, from outside surgeons: 137/173). Sixty-one percent (106/173) were newly diagnosed with neuro-ophthalmic etiologies, including 21% (36/173) with afferent and 40% (70/173) with efferent disorders. Thirty-six percent (62/173) of patients had non neuro-ophthalmic causes and 3% (5/173) had systemic conditions responsible for visual disturbances postoperatively. Decompensated strabismus causing diplopia was the most common neuro-ophthalmic diagnosis after cataract surgery (50%, 53/106). Of the 13,715 patients who had cataract surgery performed at our institution over a 9-year period, 20 of 36 patients referred for visual disturbances were identified with neuro-ophthalmic etiologies of which 85% (17/20) had postoperative diplopia.

CONCLUSIONS

In our study, decompensated strabismus causing diplopia was the most common neuro-ophthalmic visual disturbance after cataract surgery. Detailed history and ocular alignment should be assessed before cataract surgery to identify patients with the risk.

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.

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.

The Risk of Non-arteritic Ischemic Optic Neuropathy Post-intravitreal Bevacizumab Injection

OBJECTIVES

To report the incidence of non-arteritic ischemic optic neuropathy in diabetic patients treated with intravitreal bevacizumab injection.

METHODS

A prospective comparative analytic study was done in the King Hussein Medical Center during the period between June 2020 and June 2021. Inclusion criteria included diabetic patients who attended a retina clinic. Exclusion criteria included patients with pre-existing ischemic optic neuropathy. Patients were divided into two groups. The first group included diabetic patients who did not require bevacizumab injection and were treated either with follow-up visits or pan-retinal photocoagulation, and the second group included patients who were treated with intravitreal bevacizumab. Patients were followed up for a period of one year. Data collected in two groups included the total number of patients and the number of patients with non-arteritic ischemic optic neuropathy. Results were compared in both groups. A P-value was used to study the statistical significance and was considered to be statistically significant if ≤0.05.

RESULTS

The mean age for patients in group 1 was 64.3 years, with a male to female ratio of 1.1 to 1. In group 2, the mean age was 66.2 years, with a male to female ratio of 1.2 to 1. The total number of patients in group 1 was 7375, among whom 68 patients had non-arteritic ischemic optic neuropathy. While in group 2, the total number was 2468 and 49 of them had non-arteritic ischemic optic neuropathy. Most cases of non-arteritic ischemic optic neuropathy were seen in patients who had received three or more injections.  Conclusion: Intravitreal bevacizumab in diabetic patients is considered a risk factor for the development of non-arteritic ischemic optic neuropathy, especially in patients receiving more than three injections.

Risk Factors for Non-arteritic Anterior Ischemic Optic Neuropathy: A Large Scale Meta-Analysis

Objective: We conducted a meta-analysis to explore all the potential risk factors for non-arteritic anterior ischemic optic neuropathy (NAION) based on the published literature. Methods: A comprehensive literature search through the online databases was performed to obtain studies concerning the risk factors of NAION up to June 2020. Pooled unadjusted odds ratios (ORs) or rate ratios (RRs) were calculated to evaluate the weight of risk factors. This study was registered in PROSPERO under the number CRD42018084960. Results: Our meta-analysis included 49 original studies comprising of more than 10 million patients. The following risk factors were proved to be significantly associated with NAION: male gender (OR = 1.67, 95% CI: 1.50-1.85, P < 0.00001), hypertension (RR = 1.28, 95% CI: 1.20-1.37, P < 0.00001), hyperlipidemia (RR = 1.43, 95% CI: 1.26-1.62, P < 0.00001), diabetes mellitus (DM) (RR = 1.53, 95% CI: 1.36-1.73, P < 0.00001), coronary heart disease (CHD) (RR = 1.68, 95% CI: 1.24-2.27, P = 0.0008), sleep apnea (RR = 3.28, 95% CI: 2.08-5.17, P < 0.00001), factor V Leiden heterozygous (RR = 2.21, 95% CI: 1.19-4.09, P = 0.01), and medication history of cardiovascular drugs. Conclusion: We concluded that the above risk factors were significantly related to NAION. Better understanding of these risk factors in NAION can help the direct therapeutic approaches.

Evaluation of hemodynamic changes in nonarteritic anterior ischemic optic neuropathy using multimodality imaging

Background

Nonarteritic anterior ischemic optic neuropathy (NAION) patients experience hypo-perfusion in the short posterior ciliary arteries (SPCAs), however, the cause of hypo-perfusion is unclear. Real-time dynamic hemodynamic observations may provide clues into specific NAION pathogenic mechanisms. We aim to analyze hemodynamic changes occurring in NAION using multimodality imaging. Our specific focus is identifying pathogenic mechanisms underlying SPCA insufficiency in NAION.

Methods

Three-dimensional arterial spin labeling (3D ASL) magnetic resonance imaging (MRI) and three-dimensional time-of-flight (3D-TOF) magnetic resonance angiography (MRA) were performed on 25 NAION patients (50 eyes) and 22 (44 eyes) normal cases were recruited. The diameter of the initial part of the ophthalmic artery and internal carotid artery siphon were measured using MRA. Blood vessel identification and blood flow (BF) were detected using 3D ASL MRI. We measured BF values of the optic nerve head (ONH) region of the retina/choroid complex, optic nerve (ON), temporal lobe, and occipital lobe.

Results

We studied 32 NAION affected eyes, 18 NAION uninvolved eyes, and 44 normal eyes. Diameter of the initial part of ophthalmic artery in the NAION affected eyes was significantly larger than the uninvolved eyes (P=0.026). Diameter of the NAION eyes was 1.33±0.19 mm [mean ± standard deviation (SD)], uninvolved eyes were 1.15±0.21 mm. At a photolabeling delay times (PLD) of 1,500 and 2,500 ms, BF of the ONH and ON in NAION affected eyes was significantly less than uninvolved and normal eyes (pONH <0.001 both at 1,500 and 2,500 ms, pON <0.001 and pON =0.001 at 1,500 and 2,500 ms, respectively). ONH of uninvolved eyes was also significantly less than normal eyes. Additionally, BF of the ONH region correlated with temporal lobe BF, with an R²=0.3231 and 0.2397 at 1,500 and 2,500 ms, respectively. BF of the ONH region also correlated with occipital lobe BF, with an R²=0.2534 and 0.4397 at 1,500 and 2,500 ms, respectively. ON and temporal lobe BF also correlated, with an R²=0.226 and 0.1504 at 1,500 and 2,500 ms, respectively.

Conclusions

Abnormal hemodynamics of small cerebral vessels existed prior to the onset of NAION. A candidate mechanism underlying NAION appears to be transient insufficiency of blood supply and decompensation of ocular vascular regulation.

Nonarteritic Anterior Ischemic Optic Neuropathy following Herpes Zoster Ophthalmicus and Steroid-Related Intraocular Pressure Spike

A 61-year-old woman presented with sudden vision loss from a left anterior optic neuropathy in the context of severely elevated intraocular pressure after starting topical steroids for anterior uveitis related to herpes zoster ophthalmicus (HZO). The strong temporal relationship between the vision loss and elevated IOP suggested the vision loss was related to nonarteritic anterior ischemic optic neuropathy (NAION). Anterior chamber paracentesis did not detect varicella zoster virus (VZV) and magnetic resonance imaging of the orbits was normal. Her vision remained stable and the optic disc edema resolved within 3 months. The occurrence of NAION following an acute elevation of intraocular pressure (IOP) is well-documented in the context of surgical procedures, glaucoma, uveitis and trauma. This case indicates that not every optic neuropathy in close temporal relationship with HZO is directly attributable to the virus. NAION may also occur after steroid-related IOP spikes and ophthalmologists should ensure that patients on topical steroids are closely monitored for ocular complications.

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

PURPOSE

To determine if there is an increased incidence rate of post-cataract surgery (pcs) anterior ischemic optic neuropathy (AION) compared to spontaneous AION (sAION).

DESIGN

Retrospective, population-based cohort.

METHODS

Patients diagnosed with AION from January 1, 1990, through December 31, 2016, while residing in Olmsted County, Minnesota. Patients with cataract surgery preceding AION were included in the pcsAION cohort defined in 2 ways: AION within 2 months and AION within 1 year of cataract surgery. The incidence rates of pcsAION and sAION were compared using Poisson regression models.

RESULTS

During the study period, 102 residents developed AION. The median age was 65 years (range, 40-90 years), 44 (43.1%) were female. Twenty of 102 (19.6%) patients had previous cataract surgery, of which 2 and 9 developed AION within 2 months and 1 year of surgery, respectively. The annual incidence rate of pcsAION within 2 months of surgery (8.6 per 100,000) was not significantly greater than the annual incidence rate of sAION (6.9 per 100,000; P = .78). However, the annual incidence rate of pcsAION within 1 year of surgery (38.9 per 100,000) was significantly higher than the incidence rate of sAION (6.5 per 100,000; P < .001).

CONCLUSION

The incidence of AION is increased in the first year after cataract surgery, but not in the early (i.e., 2 months) postoperative period.

Ischemic optic neuropathy after Descemet-stripping automated endothelial keratoplasty

An 82-year-old woman presented with a failed Descemet-stripping automated endothelial keratoplasty (DSAEK) in her right eye performed a month earlier. The patient underwent uneventful repeat DSAEK. Six days after the procedure, the patient was found to have an afferent pupillary defect and optic nerve swelling in her right eye on fundoscopy and optical coherence tomography. A comprehensive workup, including bilateral temporal artery biopsies and magnetic resonance imaging, for vasculitic etiologies was negative. A diagnosis of nonarteritic anterior ischemic optic neuropathy (NAION) was made. Although NAION has been reported after various ocular surgeries, to the authors' knowledge, this is the first reported case of NAION after uneventful corneal transplantation. Therefore, NAION should be considered a rare complication of corneal transplantation surgery. Meticulous preoperative and postoperative evaluation, including an attentive pupillary and dilated fundus examination, are essential in assessing a patient's risk factors for this condition and monitoring for its occurrence in the perioperative period.