Fundus Features Relate to Severity of Visual Field Loss in Acute Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION)

Abstract

Purpose : Numerous studies report a significant correlation between fundus features and visual loss in macular disorders and in glaucoma. To date, there are no such studies in non-arteritic anterior ischemic optic neuropathy (NAION). We aimed to correlate fundus features of the optic nerve head (ONH) and peripapillary retina with visual field (VF) loss in acute NAION.

Methods : We analyzed the presenting features of 728 fundus photos for study eyes with acute NAION from the Quark trial. Participants were assessed <14 days (median 8.0 ±3.2 days) from vision loss start.

We identified and segmented features related to ONH swelling and then graded images based on the level of vessel obscuration for each ONH quadrant. We created a total swelling score by combining scores for obscuration and elevation. Other features recorded included: hemorrhages; cotton wool spots; disc hyperemia; pallor; and peripapillary wrinkling.

Using the average total deviation (TD), we categorized VF loss at screening as either ‘Moderate’(>-12dB), ‘Severe’(-12dB to -20dB) or ‘Profound’(<-20dB). XGBoost was used with an 80:20 train:test split to predict vision loss severity from the swelling score and presenting features.

Results : Of the 728 images, 86.2% (620) had ONH hyperemia; 77.9% (568) had hemorrhages; 27.4% (200) had cotton wool spots; 21.1% (154) had pallor; and 14.5% (106) had peripapillary wrinkling of the retina or choroid.

VF data for 679 eyes showed a mean TD of -18.5 dB (+/-7.5). 21.1% (143) had moderate; 39.6% (269) severe; and 39.3% (267) had profound VF loss, respectively. Although individual features revealed only weak associations with VF loss severity (total swelling: 0.13; total elevation: 0.13; wrinkles 0.11; pallor 0.09; hyperemia -0.11), combining feature input through utilization of an XGBoost model resulted in an accuracy of 73.6% and an average F1-score of 76.4% at classifying level of VF loss.

Conclusions : We report the first large prospective correlation of fundus features with the severity of visual field loss in acute NAION. We note that pallor of the ONH is common. Future investigation will seek to assess how structural features evolve with time and their relation to VF at outcome.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Fig 1. Frequency of features of NAION at enrollment

 

Fig 2. Predictions of XGBoost model versus ground truth visual field loss categories