Explainable Artificial Intelligence-Assisted Exploration of Clinically Significant Diabetic Retinal Neurodegeneration on OCT Images.

Purpose: To explore clinically significant diabetic retinal neurodegeneration in OCT images using explainable artificial intelligence (XAI) and subsequent evaluation by retinal specialists. Design: A single-center, retrospective, consecutive case series. Participants: Three hundred ninety-seven eyes from 397 diabetic retinopathy patients for XAI-based screening and 244 fellow eyes for subjective human evaluation. Methods: We acquired 30° horizontal OCT images centered on the fovea. An artificial intelligence (AI) model was developed to infer visual acuity (VA) reduction using fine-tuned RETFound-OCT. Attention maps highlighting regions contributing to VA inference were generated using layer-wise relevance propagation. Retinal specialists assessed OCT findings based on salient regions indicated by XAI. Two newly described findings, a needle-like appearance of the ganglion cell layer (GCL)/inner plexiform layer (IPL) ("ice-pick sign") and dot-like alterations in the outer nuclear layer (ONL) ("salt-and-pepper sign"), were evaluated alongside 2 established findings: EZ disruption and choroidal hypertransmission. Main Outcome Measures: Identification of clinically significant OCT findings associated with diabetic retinal neurodegeneration. Results: The AI model effectively discriminated eyes with poor vision (decimal VA ≤0.5) from those with good vision (VA ≥1.0) (area under the receiver operating characteristic curve of 0.947). Explainable artificial intelligence-based attention maps highlighted salient regions in the GCL/IPL (65.2% or 70.0%), ONL (52.2% or 28.3%), EZ (39.1% or 21.7%), and choroid (26.1% or 5.00%) in eyes with poor or good vision, respectively. Subjective evaluation by retinal specialists revealed the frequencies of these 4 findings as follows: ice-pick sign (32.4%), EZ disruption (25.0%), salt-and-pepper sign (16.0%), and choroidal hypertransmission (13.5%). Eyes with decimal VA ≤0.9 had these findings more frequently than those with VA ≥1.0 ( Conclusions: Artificial intelligence-assisted exploration of OCT findings identified 2 established lesions and 2 novel OCT biomarkers indicative of clinically significant diabetic retinal neurodegeneration. Financial Disclosures: The author(s) have no proprietary or commercial interest in any materials discussed in this article.