Intraretinal hyperreflective line: potential biomarker in various retinal disorders.

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Diseases

Background:

• The intraretinal hyperreflective line (IHL) is a newly identified finding on optical coherence tomography (OCT).
• IHL is believed to represent a reactive response to damage in photoreceptors, Muller cells, or retinal pigment epithelium.
• This study aimed to characterize IHLs using spectral-domain OCT and identify associated retinal conditions.

Purpose of the Study:

• To analyze the spectral-domain OCT characteristics of intraretinal hyperreflective lines (IHLs).
• To determine the prevalence of IHLs in various retinal diseases.
• To investigate potential causative factors associated with IHL detection.

Main Methods:

• Retrospective review of OCT imaging and clinical records from January 2019 to August 2023.
• Inclusion criteria: detection of IHL on good-quality spectral-domain OCT B-scans.
• Definition of IHL: a vertical line from the ellipsoid zone through the outer nuclear layer to the internal limiting membrane in the central fovea.

Main Results:

• IHLs were observed in 40 eyes across 38 participants with diverse retinal diseases.
• Commonly associated conditions included prior vitreoretinal surgery (35%), macular holes (microhole 15%, lamellar 10%), diabetic macular edema (7.5%), and MacTel-2 (7.5%).
• IHLs were also found in eyes with vitreomacular traction, retinal artery occlusion, commotio retinae, AMD, ERM, uveitis, and Coats' disease.

Conclusions:

• Intraretinal hyperreflective lines (IHLs) are not exclusive to vitreomacular surface diseases.
• IHLs can be present in a wider spectrum of retinal pathologies.
• Further large-scale, multicenter studies are needed to fully understand the significance of IHLs as an OCT biomarker.