Degeneration of photoreceptors, retinal cells including retinal pigment epithelium, and retinal ganglion cells characterizes visual disorders involving retinal dysfunction. The efficient and targeted gene delivery into retinal cells is critical for treatment of a variety of visual disorders. Here, we report use of an OCT guided, spatially targeted, near-infrared laser microirradiation platform to successfully deliver genes encoding ambient-light activatable multi-characteristic opsin (MCO) to retinal cells in non-human primates. The efficacy of gene delivery was evaluated by fundus imaging of the reporter (mCherry) fluorescence, and immunohistochemistry. Functional improvement was measured by red-ERG which was attributed to MCO’s broadband activation spectrum.
Stargardt Disease is an inherited macular degeneration caused by mutation of genes, primarily ABCA4 in the photoreceptor cells leading to their dysfunction and degeneration in the macula. Here, we report results of ambient-light vision restoration in Stargardt mice (Abca4tm1Ght/J) upon intravitreal delivery of AAV-carried MCO (vMCO) as evaluated by electrophysiology, Optical Coherence Tomography (OCT) and visually guided behavior. Further, safety of MCO-enabled vision restoration therapy was evaluated by measurement of Intraocular Pressure, OCT and Immunohistochemistry. The vMCO based ambient light activatable optogenetic therapy has potential to be a disease-agnostic therapy to address the unmet need of inherited retinal degenerative diseases.
We combine the real-time structural imaging capability of OCT with laser microirradiation for causing layer-specific dystrophies to mimic Retinitis Pigmentosa and dry-AMD model. In addition, we integrated an ERG-module for functional characterization after laser-injury to monitor the disease progression as well as to evaluate therapeutic efficacy. Here, we show creation of local atrophies with our combined OCT-Laser-ERG system in animal models and measurement of different cone and rod responses to focal stimulation light of different wavelengths. By varying the different mode of laser microirradiation and focal adjustment to the targeted depth, we demonstrate layer specific primary RPE injury.
We hypothesized that PEDF gene transduction in retina can provide single-dose treatment to prevent ganglion cell damage. Here, we present OCT guided ultrafast laser based non-viral targeted delivery PEDF-encoding genes to retina for neuroprotection. The ultrafast laser gene delivery showed layer-specific reliable expression of PEDF gene in retina without any detectable damage. Monitoring of IOP and electroretinogram after ultrafast laser transfection showed no adverse changes. The ultrafast laser transfection of large PEDF genes in retina exhibited significant therapeutic benefit in an injury model. Absence of any immune response in retina subsequent to ultrafast-laser transfection provides unique opportunity for repeated dosing.
Herein, we report use of near-infrared low-coherent light for non-contact, label-free in-vivo detection of retinal activity in response to visual illumination. Our multifractal phase-OCT employ phase/multifractal analysis to decipher layer specific cellular activity during visual stimulation to assess the functional state of retina. Our OCT-based interferometric technique coupled with in-depth multifractal analysis differentiated retinal activities between wild-type and mice with retinal dystrophy. Our findings open up possibility of clinical translation of multifractal phase-OCT for non-contact label free evaluation of retina health, progression of retinal dystrophies, and as well as for monitoring functional recovery after therapy.
Optical coherence tomography (OCT) is currently recognized as the gold standard for identifying retinal structural abnormalities in ophthalmology. However, its availability is often limited to large eye centers and research labs due to its high cost and lack of portability. We present a low-cost, portable spectral-domain OCT system with a total cost of materials under $6,000. Compared to current commercial systems, our design offers 50% size reduction and over 80% cost reduction. Image acquisition interface is incorporated and displayed onto a mounted 7-inch touchscreen. Human retinal imaging is demonstrated, and performance is compared with a commercial OCT system. Based on contrast-to-noise ratio analysis, the low-cost OCT demonstrates comparable imaging capabilities.
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