Evaluation of Choroidal Thickness in Non-arteritic Anterior Ischaemic Optic Neuropathy at the Acute and Chronic Stages

Assessment of macular and peripapillary choroidal thickness in non-arteritic anterior ischemic optic neuropathy: A meta-analysis

BACKGROUND

Non-arteritic anterior ischemic optic neuropathy (NAION) is the most common optic neuropathy in adults aged ≥ 50 years. Transient non-perfusion or hypoperfusion of the optic nerve head circulation is believed to be the underlying cause of NAION. It has been suggested that peripapillary choroidal thickness (PCT) is altered after ischemic disorders of the optic nerve head, but the results have not always been consistent. To address this issue and provide evidence for the pathogenesis of NAION, we performed a meta-analysis to systematically evaluate macular choroidal thickness (MCT) and PCT in patients with NAION.

METHODS

A comprehensive literature search of PubMed, Embase, Cochrane Library, and Web of Science databases was performed until August 31, 2022. The main inclusion criterion was a case-control study in which MCT and PCT were measured using optical coherence tomography in patients with NAION. Mean difference (MD) and 95% confidence interval were calculated for continuous estimates. The Review Manager (V5.40) was used for the analysis.

RESULTS

Nine studies comprising 663 eyes (283 NAION eyes and 380 healthy control eyes) were included (Newcastle-Ottawa Scale score ≥ 5). MCT and PCT were higher in eyes with chronic NAION (MD = 19.16, P = .04; MD = 35.36, P < .00001) and NAION fellow eyes (MD = 30.35, P = .0006; MD = 29.86, P = .04) than in healthy controls. No difference was noted in the MCT between eyes with acute NAION and healthy controls (MD = 2.99, P = .87).

CONCLUSION

Increased MCT and PCT may be important anatomical and physiological features of the eyes in patients with NAION.

Choroidal Thickness in Acute Non-arteritic Anterior Ischemic Optic Neuropathy

Purpose

To compare the choroidal thickness in eyes with acute non-arteritic anterior ischemic optic neuropathy (NAION) with healthy contralateral eye and normal controls.

Methods

Thirty-eight eyes with NAION, thirty-eight unaffected fellow eyes, and seventy-four eyes from 37 healthy, age- and sex-matched subjects were included in this prospective comparative case-control study. Choroidal thickness was measured by enhanced depth imaging (EDI) of spectral domain optical coherence tomography (SD-OCT). Peripapillary choroidal thickness (PCT) was measured at 1000 and 1500 μm from Bruch's membrane opening (BMO). Subfoveal choroidal thickness (SFCT) was measured in central subfoveal area, and 500 microns apart in temporal and nasal sides. Choroidal thickness among NAION eyes, uninvolved fellow eyes, and control eyes were compared.

Results

The mean of PCT at 1000 μm was significantly thicker in NAION and fellow eyes compared to control eyes (169.7 ± 47, 154.4 ± 42.1, and 127.7 ± 49.9 μm, respectively, P< 0.001 and P = 0.42). The mean PCT at 1500 μm was also significantly thicker in NAION and fellow eyes compared to control eyes (178.6 ± 52.8, 162.6 ± 46.1, and 135.1 ± 59 μm, respectively, P = 0.007 and P = 0.048). The mean PCT at 1000 and 1500 μm was significantly greater in NAION compared to fellow eyes (P = 0.027 and P = 0.035, respectively). The mean of SFCT was significantly thicker in NAION compared to control eyes (P = 0.032); however, there was no significant difference between uninvolved fellow and control eyes (P = 0.248).

Conclusion

Thicker choroidal thickness in acute NAION and uninvolved fellow eyes compared to normal eyes suggests a primary choroidal role in NAION pathophysiology.

Choroidal Vascular Changes in Arteritic and Nonarteritic Anterior Ischemic Optic Neuropathy

PURPOSE

To compare choroidal vascularity index (CVI) in patients with arteritic anterior ischemic optic neuropathy (A-AION), nonarteritic anterior ischemic optic neuropathy (NA-AION), and control subjects.

DESIGN

Retrospective cross-sectional study.

METHODS

This study was conducted at the Ophthalmology Unit of the S.Orsola-Malpighi University Hospital (Bologna, Italy). Macular and optic nerve head optical coherence tomography (OCT) scans of 20 patients with A-AION secondary to giant cell arteritis (biopsy-proven), 20 patients with NA-AION, and 20 control subjects were acquired with Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany). Images were binarized using ImageJ software, and total choroid area (TCA), luminal area (LA), and stromal area (SA) were segmented. The main outcome measure was CVI, defined as the ratio of LA to TCA.

RESULTS

Patients with A-AION showed a significantly lower macular and peripapillary CVI compared to both patients with NA-AION (respectively, 67.17 ± 2.35 vs 69.66 ± 4.18, P = .048; 63.51 ± 3.29 vs 67.67 ± 3.07, P < .001) and control subjects (respectively, 67.17 ± 2.35 vs 70.00 ± 2.95, P = .021; 63.51 ± 3.29 vs 68.69 ± 3.19, P = .002). Conversely, no significant difference in macular and peripapillary CVI was found between patients with NA-AION and controls (respectively, P = .942 and P = .570). After adjustment for age, the difference of peripapillary CVI among groups remained statistically significant (P < .001), while the difference in macular CVI did not (P = .060).

CONCLUSIONS

Macular and peripapillary CVI are reduced in patients with A-AION. These parameters may be useful to quantitatively evaluate choroidal vascular dysfunction in A-AION, serving as a new additional diagnostic tool to distinguish A-AION from NA-AION.