High resolution optical coherence tomography reveals details of regeneration after selective retina therapy

Purpose : To investigate the course of retinal regeneration after selective retina therapy (SRT) using high-resolution spectral-domain optical coherence tomography (High-Res-OCT).
Methods : Imaging data origin from the CENTAURUS study. SRT was performed in patients with diabetic retinopathy using the SPECTRALIS CENTAURUS device (HuCE-optoLab, BFH-TI, Switzerland). SRT laser lesions were observed over a follow-up period of 6 months using High-Res-OCT (Heidelberg Engineering, Germany). High-Res-OCT enables imaging with increased axial resolution of up to 3 µm due to increased bandwidth of 130 nm (central wavelength: 840 nm) compared to conventional spectral-domain OCT devices (bandwidth: 40 nm, axial resolution 7 µm).
Results : Up to 90 laser lesions with different laser pulse energy in the retina of two subjects were analyzed over a follow-up period of six months. Laser lesions, especially those with higher laser pulse energy lead to an initial hyperreflectivity in the outer retinal layers, which disappeared within the first week. After one week, a local proliferation and hyperreflectivity on the level of the retinal pigment epithelium (RPE) was observed, which normalized over the course of six months. At the final visit, no remaining retinal changes after SRT laser were detectable using High-Res-OCT.
Conclusions : The increased axial resolution makes High-Res-OCT a great imaging tool for detection of subtle retinal changes after SRT, and for follow-up over time. SRT lesions especially lead to focal proliferation in the level of the RPE with regeneration over time without observation of permanent scar formation or induction of neovascularization.