Abstract
Purpose :
Laser lesioning is a robust method for studying retinal photodamage and modeling human pathologies in small animals. Optical coherence tomography (OCT) and scanning laser ophthalmoscopy (SLO) uniquely enable non-invasive access to in vivo cellular and subcellular retinal anatomy without the need to excise tissues. Here, we demonstrate a combined OCT and SLO ophthalmic imaging system with an integrated scanning laser lesioning module optimized for the murine retina.
Methods :
OCT imaging was performed using a custom-designed spectrometer at 875±75 nm at 70 kHz line-rate. SLO images were acquired at 7.8 frames-per-second with optimized detection for tdTomato excited fluorescence. A 532 nm photocoagulation laser was folded into the combined imaging pathway. Custom LabView control software was developed to steer the photocoagulation laser to targets-of-interest using an en face OCT projection and initiate laser delivery. Targeted retinal laser lesioning using various laser pulse parameters was performed on 6 transgenic mice (12 eyes) expressing tdTomato in Müller cells. OCT and SLO images were acquired before injury and once a week until 21-days post-lesion.
Results :
Longitudinal changes from laser lesions induced with various pulse parameters including pulse duration, pulse power, number of pulses, and extended area delivery were visualized. We show structural changes within specific retinal layers in the OCT cross-sections as well as cellular damage and response in SLO images. We also demonstrated real-time OCT-visualization of laser lesion formation, which can be used to provide real-time feedback on lesion severity.
Conclusions :
We performed observational studies on the effects of pulse duration, pulse power, and number of pulses on lesion severity and extended area lesioning using a novel OCT-guided laser lesion targeting system. We believe the proposed system will benefit the repeatability and precision of existing laser lesion models of ocular pathologies and photodamage response.
This is a 2020 ARVO Annual Meeting abstract.