Intraretinal hyperreflective line: potential biomarker in various retinal disorders.

Background: The intraretinal hyperreflective line (IHL) is a novel posterior segment finding demonstrable using careful optical coherence tomography (OCT) examination. It likely indicates a reaction against photoreceptor, Muller cell, and/or retinal pigment epithelial damage. This study analyzed the spectral-domain OCT characteristics of IHLs to disclose their presence in various retinal conditions.

Methods: A retrospective review of the charted and imaging records of participants with IHL was conducted at Dokuz Eylul University Department of Ophthalmology between January 2019 and August 2023. The inclusion criterion was the detection of an IHL on good-quality B-scan spectral-domain OCT. An IHL was defined as a vertical line extending from the ellipsoid zone band (or lower) through the outer nuclear layer to the internal limiting membrane in the central fovea. Associated retinal conditions were recorded as potential causative factors for the presence of IHL.

Results: IHL was observed on spectral-domain OCT in 40 eyes of 38 participants with several retinal diseases assessment. Fourteen eyes (35%) underwent vitreoretinal surgery pre-IHL detection (12 were operated for full-thickness macular hole [FTMH], one for epiretinal membrane [ERM], and one for rhegmatogenous retinal detachment). In six eyes (15%) a microhole coexisted. Four eyes (10%) had a concurrent lamellar macular hole. The IHL preceded the occurrence of FTMH in three eyes (7.5%), and diabetic macular edema and type 2 idiopathic macular telangiectasia (MacTel-2) were present in three eyes (7.5%) each. The remaining conditions included vitreomacular traction (VMT), nonarteritic anterior ischemic optic neuropathy with central retinal artery occlusion, commotio retinae, exudative age-related macular degeneration, ERM, non-infectious idiopathic posterior uveitis, and Coats' disease, each affecting one eye (2.5%). Of the two participants with bilateral involvement, one was diagnosed with MacTel-2 and the other had IHL with VMT in the right eye that was detected post-vitreoretinal surgery for FTMH in the left eye.

Conclusions: Although IHLs are mostly identified in eyes with vitreomacular surface diseases, clinicians may encounter IHLs in other types of retinal pathology. Further large-scale, multicenter, long-term studies on the presence of IHLs in OCT imaging are required to provide more substantial insight on this biomarker.