Table 2.
The early optical coherence tomography (OCT) findings in idiopathic macular telangiectasia type 2 (MacTel type 2).
| OCT Features | Description |
|---|---|
| Enlarged foveal pit | A thin temporal juxtafoveal retina leads to enlargement of the foveal pit in the temporal region (thinning takes place in the outer nuclear/Henle’s fiber layer) [63]. |
| Hypo-reflective cavities |
Located in both inner and outer neurosensory retina [68]. |
| Disruptions of retinal layers | Disruption of the external limiting membrane (ELM), photoreceptor inner segment–outer segment border, and interdigitation zone—one of the most frequently observed OCT features in patients with idiopathic macular telangiectasia type 2 [68]. |
| Thicker temporal retina |
Early subretinal neovascularization may be indicated by a thicker temporal retina compared to nasal fovea without retinal fluid [69]. |
| Hyper-reflective lesions | Thick, hyper-reflective lesions in the outer retina, with highly reflective dots in the inner and the outer nuclear layers [69]. |
| Decrease in vascular density | In type 2 MacTel, the earliest vascular changes are observed in the deep vascular plexus, which are characterized by a decrease in vascular density and the presence of telangiectatic vessels (changes can be visualized using OCT angiography) [70]. |
| Hyperreflective middle retinal layer (MRL) |
Loss of Müller cells in the perifoveal region may contribute to increased hyperreflectivity of MRL [70,71,72]. In type 2 MacTel, hyperreflective MRL in the perfoveal region was recognized as the most frequent early OCT finding [71]. |
| Superficial intraretinal crystals | Lesions present in all stages of disease provide evidence of Müller cell involvement. Useful for early disease diagnosis [71]. |
| Retinal pigment clumps (RPC) | The presence of retinal pigment clumps can potentially serve as an early indicator or biomarker for predicting the onset of the proliferative stage of the disease [71]. |
| Clustered hyperreflective foci (HF) | Clustered hyperreflective foci are the early biomarker of the neurodegenerative process; additional research is needed [73]. |