Purpose: To determine the best imaging procedure for the definition of tangential tractions generated by epiretinal membranes in lamellar macular holes.
Methods: Inclusion criteria were a diagnosis of lamellar macular hole with tractional epiretinal membranes based upon fundus autofluorescence (FAF), and spectral-domain optical coherence tomography (SD-OCT) imaging (HRA + OCT Spectralis, Heidelberg Engineering, Heidelberg, Germany). Tangential tractions were evaluated with infrared reflectance (IR; 820 nm) and OCT en face (193 B-scans, 30 × 20°pattern size, 31 μm between two consecutive B-scans). Three different categories of tangential traction were previously defined: 1) unidirectional, 2) pluridirectional, and 3) concentric. Two independent masked physicians evaluated the images in order to categorize the type of tangential traction either with IR and OCT (en face) for every single patient. Cohen's kappa statistic was used to evaluate inter-observer and inter-instrument agreement.
Results: Twenty eyes of 19 patients were included in the study. Inter-observer OCT test showed almost perfect agreement between examiners (κ = 0.86). Inter-observer IR test showed substantial agreement (κ = 0.7). Inter-instrument agreement was fair for both observers, respectively κ = 0.35 for observer 1 and κ = 0.22 for observer 2. Intra-observer agreement was almost perfect for OCT (κ = 0.93) and substantial for IR (κ = 0.78).
Conclusion: Tangential traction associated with epiretinal membranes in lamellar macular holes can be successfully evaluated by OCT en face and IR reflectance. Inter-observer concordance is high for both instruments. However, high inter-instrument discordance is present. Therefore, the gold standard imaging technique for differentiating the different types of contraction in epiretinal membranes has still to be determined.
Keywords: Epiretinal membrane; Infrared reflectance; Lamellar macular hole; Spectral-domain optical coherence tomography; Tangential traction.