Our white paper on adaptive optics for ophthalmoscopy is out. It makes the case for the Deformable Phase Plate in retinal imaging: a corrector with the reach of a deformable mirror and the in-line simplicity of a transmissive modulator, in an instrument compact enough to leave the research bench.
Why the retina needs adaptive optics
Diseases of the visual system often show first as subtle changes in the layers of the retina — which makes the eye a window not only to the world but to our health. Ophthalmoscopy images those layers at high magnification, and it is the eye’s own imperfections that limit it: the aberrations of cornea and lens keep a conventional ophthalmoscope from resolving retinal features at the cellular level, and with them the early signs of major eye diseases. Adaptive optics, borrowed from astronomy, was introduced to ophthalmoscopy nearly three decades ago and let researchers observe cellular and subcellular structures of the living retina for the first time.
What the white paper shows
Conventional AO systems are complex, large and expensive, which has confined them to optical tables in research institutes. The refractive approach simplifies the implementation: the DPP sits in line, close to the eye, and needs neither a folded beam path nor relay optics. In a study with the Institut Langevin in Paris, an existing research-grade ophthalmoscope was retrofitted with a DPP-based AO system; the retrofitted instrument resolved single photoreceptors and gained significantly in signal-to-noise ratio (the retinal images above; scale bar 15 µm).
Retrofitting existing ophthalmoscopes rather than replacing them is the point: it is the route to compact, affordable and widely accessible retinal imaging.
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