Triple Layer sign on OCT useful diagnostic tool for diagnosing non-exudative macular neovascularization: Study

treatment-naïve non-exudative type-1 macular neovascularization (NE-MNV) in age-related macular degeneration (AMD) can be quite challenging to diagnose. Optical coherence tomography is done to detect three layers, such as the retinal pigment epithelium, neovascular tissue, and Bruch's membrane, to identify neovascularization. This is called the triple-layer sign. Researchers from the Department of Ophthalmology in France and Italy conducted a study to assess the sensitivity and specificity of the “triple layer sign” that can be used to diagnose treatment-naïve non-exudative type-1 macular neovascularization (NE-MNV) in age-related macular degeneration (AMD).

Two masked retinal experts conducted a cross-sectional study to evaluate the presence of TLS in eyes with NE-MNV. Individuals with a retinal pigment elevation without exudation due to other causes than NE-MNV in AMD, such as medium-large drusen, cuticular drusen, and basal laminar deposits (BlamD), were used as controls.

Findings:

• About 130 eyes of 98 consecutive patients who met the inclusion criteria were involved in the study.
• A total of 40 eyes from 40 patients met the criteria for NE-MNV secondary to the AMD group.
• They included 27 females and 13 males, with a mean age of 73.8 ± 8.0 years.
• About 90 eyes of 58 patients were added to the control group.
• About 31 eyes were included in the medium-to-large drusen sub-group, 32 in the cuticular drusen sub-group, and 27 in the BlamD group.
• On structural OCT, non-exudative MNV shows TLS defined as triple hyper-reflective bands on OCT frames.
• The TLS was observed in 39/40 patients with NE-MNV and 8/90 controls.
• The first band corresponded to the retinal pigment epithelium (RPE), the second band with the neovascular tissue (flash), and a less reflective band was observed near the second band. The third hyper-reflective band represented Bruch's membrane (BM).
• The sensitivity and specificity of the TLS for diagnosing NE-MNV were 97% and 91%, respectively.

Thus, the authors concluded that the triple-layer sign representing the retinal epithelium neovascular tissue and Bruch’s membrane displayed high sensitivity and specificity. This underscores the importance of using the triple-layer sign for early detection and treatment planning, as it is a noninvasive diagnostic approach that also helps improve diagnostic accuracy.

Further reading: Capuano, V., Sacconi, R., Miere, A. et al. The “triple-layer sign”: an optical coherence tomography signature for the detection of non-exudative macular neovascularization. Graefes Arch Clin Exp Ophthalmol 262, 3847–3855 (2024). https://doi.org/10.1007/s00417-024-06585-9.

Take-home points:

• In this study, the authors investigated the utility of the "triple-layer sign" (TLS) in diagnosing non-exudative macular neovascularization (NE-MNV) in patients with age-related macular degeneration.
• Optical coherence tomography was performed to identify three layers (retinal pigment epithelium, neovascular tissue, and Bruch's membrane). Overall, 40 of 130 eyes demonstrated evidence of NE-MNV.
• The TLS was observed in 39 of 40 patients with NE-MNV, compared with 8 of 90 patients in the control group. The overall sensitivity of the TLS for diagnosing NE-MNV was 91%, with a specificity of 97%. Inter-rater agreement for the identification of the TLS was also high.
• The TLS may represent a valuable diagnostic tool for identifying NE-MNV in patients with age-related macular degeneration.