Self-examination low-cost full-field OCT (SELFF-OCT) for patients with various macular diseases.

PURPOSE: The treatment guidelines for many macular diseases rely on frequent monitoring with optical coherence tomography (OCT). However, the burden of frequent disease control leads to low therapy adherence in real life. OCT home monitoring would address this issue but requires an inexpensive and self-operable device. With self-examination low-cost full-field OCT (SELFF-OCT), our group has introduced a novel technology that may fulfill both requirements. In this pilot study, we report the initial experiences with a clinical prototype. METHODS: Fifty-one patients with different macular diseases were recruited in a cross-sectional study. The most common diseases were age-related macular degeneration (AMD; 39/51), diabetic macular edema (DME; 6/51), and retinal vein occlusion (RVO; 3/51). Patients received a short training in device usage and then performed multiple self-scans with the SELFF-OCT device. For comparison, scans with a standard clinical spectral domain (SD-)OCT were taken. RESULTS: After a brief training, 77% of the patients were able to successfully acquire images that were clinically gradable. No significant influence on success could be found for age (p = 0.08) or BCVA (p = 0.97). Relevant disease biomarkers in the most common retinal diseases could be detected. CONCLUSIONS: SELFF-OCT was used successfully for retinal self-examination and in the future could be used for retinal home monitoring. Future improvements in technology are expected to improve success rates and image quality. TRIAL REGISTRATION: The Trial was registered in the German Trial Register under the number DRKS00013755 on 14.03.2018.

[Effect of Selective Retina Therapy (SRT) on the Inflammatory Microenvironment of the Subretinal Space]. / Einfluss der Selektiven Retinatherapie (SRT) auf inflammatorische Zellmediatoren des subretinalen Raums.

PURPOSE: To investigate the effect of Selective Retina Therapy (SRT) on inflammatory key factors such as complement factor-C3 (CC3), tumor growth factor-beta2 (TGF-ß2), tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ). MATERIALS AND METHODS: Porcine RPE-Bruch's membrane-choroid explants were irradiated with two SRT laser systems, SRTYLF and SRTYAG (Nd : YLF laser, wave length 527 nm, pulse duration 1.7 µs and Nd : YAG laser, wave length 532 nm, pulse duration 2.4 - 3 µs). Laser irradiation was performed on a spot size of 200 × 200 µm, 30 pulses, with a repetition rate of 100 Hz, and a radiant exposure of 140 (threshold RPE death) and 180 mJ/cm2 per pulse (above threshold RPE death). Explants were cultivated in modified Ussing chambers and culture viability was assessed by calcein-AM cell staining. Secretion of inflammatory factors was analyzed by ELISA. Protein expression of tissue explants was assessed by Western blot. RESULTS: Regeneration of RPE was observed after 4 days. One day after SRT with 140 mJ/cm2 per pulse the secretion of basal CC3 decreased in ELISA. Following 180 mJ/cm2 radiant exposure, the level of IFN-γ decreased at day 4. CONCLUSION: SRT does not induce the release of the pro-inflammatory factors analyzed in this in-vitro study.

Retinal volume change is a reliable OCT biomarker for disease activity in neovascular AMD.

PURPOSE: Current algorithms for automated computer interpretation of optical coherence tomography (OCT) imaging of patients suffering from neovascular age-related macular degeneration (AMD) mostly rely on fluid detection. However, fluid detection itself and correct interpretation of the fluid currently limits diagnostic accuracy. We therefore performed a detailed analysis of the requirements that would have to be met for fluid detection approaches. We further investigated if monitoring retinal volume would be a viable alternative to detect disease activity. METHODS: Retrospective analysis and manual grading of 764 OCT volume scans of 44 patients with exudative AMD treated with intravitreal anti-VEGF injections at a pro-re-nata (PRN) treatment regimen for at least 24 months. RESULTS: Detection of subretinal fluid (SRF) or intraretinal fluid (IRF) alone is not sufficient for disease detection. A combination of SRF and IRF can detect disease activity with a sensitivity of 98.6% and a specificity of 82%. With further characterization of IRF into exudative and degenerative cysts, specificity can be increased to 100%. However, correct characterization is currently not achieved by published fluid detection approaches. Change of macular retinal volume (MRV) can depict disease activity with sensitivity of 88.4% and specificity of 89.6%. Combination with the detection of SRF can further improve diagnostic accuracy to a specificity of 93.3% and sensitivity of 93.9% without relying on IRF or IRF characterization. CONCLUSION: Fluid detection without further characterization is not sufficient for AMD monitoring. Either further distinction between exudative and degenerative cysts is necessary, or other activity markers have to be taken into account. MRV offers good potential to fill this diagnostic gap and might become an important monitoring marker.

Power-controlled temperature guided retinal laser therapy.

Laser photocoagulation has been a treatment method for retinal diseases for decades. Recently, studies have demonstrated therapeutic benefits for subvisible effects. A treatment mode based on an automatic feedback algorithm to reliably generate subvisible and visible irradiations within a constant irradiation time is introduced. The method uses a site-individual adaptation of the laser power by monitoring the retinal temperature rise during the treatment using optoacoustics. This provides feedback to adjust the therapy laser power during the irradiation. The technique was demonstrated on rabbits in vivo using a 532-nm continuous wave Nd:YAG laser. The temperature measurement was performed with 523-nm Q-switched Nd:YLF laser pulses with 75-ns pulse duration at 1-kHz repetition rate. The beam diameter on the fundus was 200 µm for both lasers, respectively. The aim temperatures ranged from 50°C to 75°C in 11 eyes of 7 rabbits. The results showed ophthalmoscopically invisible effects below 55°C with therapy laser powers over a wide range. The standard deviation for the measured temperatures ranged from 2.1°C for an aim temperature of 50°C to 4.7°C for 75°C. The ED50 temperature value for ophthalmoscopically visible lesions in rabbits was determined as 65.3°C. The introduced method can be used for retinal irradiations with adjustable temperature elevations.