Photoacoustic ophthalmoscopy for in vivo retinal imaging

Abstract

We have developed a non-invasive photoacoustic ophthalmoscopy (PAOM) for in vivo retinal imaging. PAOM detects the photoacoustic signal induced by pulsed laser light shined onto the retina. By using a stationary ultrasonic transducer in contact with the eyelids and scanning only the laser light across the retina, PAOM provides volumetric imaging of the retinal micro-vasculature and retinal pigment epithelium at a high speed. For B-scan frames containing 256 A-lines, the current PAOM has a frame rate of 93 Hz, which is comparable with state-of-the-art commercial spectral-domain optical coherence tomography (SD-OCT). By integrating PAOM with SD-OCT, we further achieved OCT-guided PAOM, which can provide multi-modal retinal imaging simultaneously. The capabilities of this novel technology were demonstrated by imaging both the microanatomy and microvasculature of the rat retina in vivo.

Novel Retinal Imaging Technologies

“…This article demonstrated high-resolution PAI of ex vivo eyes. Zhang et al, [22] showed a system simultaneously acquired photoacoustic ophthalmoscopy (PAOM) and OCT B-scan images of eyes. They demonstrate contrast mechanism of PAOM is that the stronger the optical absorption, the stronger the generated ultrasonic signals.…”

Array-Based Real-Time Ultrasound and Photoacoustic Ocular Imaging

“…Moreover, a photoacoustic imaging system, such as a transducer and a data acquisition unit, is similar to a conventional ophthalmic ultrasound imaging system and effectively combined with it so that it is feasible to offer mechanical and morphological information in addition to functional and cellular data [10,11]. However, recent studies related to photoacoustic ophthalmic imaging have been mostly based on a single element detector and focused on assessment of microscopic structure, which is confined to limited field of view and far from fully utilizing potentials and advantages of photoacoustic imaging techniques [12][13][14].…”

Automated segmentation and quantitative study of retinal pigment epithelium cells for photoacoustic microscopy imaging

“…Thus, it plays an important role in the maintenance of retinal homeostasis and is implicated in a majority of retinal diseases due to the failure of RPE functions [3][4][5] . An imaging method to examine RPE cells for retinal pathological analysis is needed.Photoacoustic microscopy (PAM) is a noninvasive and label-free three-dimensional imaging modality based on the optical absorption property of biological tissues [6][7][8][9] , which has proved its capacity for in vivo imaging of blood vessels and RPE in fundus [10][11][12][13] . To achieve the cellular or subcellular imaging level, PAM systems have been developed to achieve micrometer or submicrometer resolution and used for imaging red blood cells and pigment cells [7,14,15] .…”