Purchase this article with an account.
Kristen Hagan, Theodore DuBose, Ruobing Qian, Jongwan Park, Ryan P McNabb, Joseph A Izatt, Sina Farsiu; Design and fabrication of the first handheld multimodal adaptive optics scanning laser ophthalmoscope. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4604.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Visualization of individual photoreceptors with current generation large footprint tabletop adaptive optics (AO) scanning laser ophthalmoscope (SLO) systems is largely limited to upright, cooperative patients. We previously described the first confocal handheld AOSLO (HAOSLO) system for imaging supine subjects and young children. Yet, reliable quantification of photoreceptor structures requires access to backscattered and mutiply scattered light imaging channels. Here, we describe the first multimodal HAOSLO system which includes both confocal and non-confocal split detector channels.
A compact deformable mirror (DM) was used as the adaptive element to correct for wavefront distortions. The confocal collection fiber of previous handheld AOSLO system was replaced with a custom fiber bundle containing one confocal and two non-confocal channels, enabling collection of left and right scattered light essential for split-detection. Wavefront-sensorless aberration correction was achieved using a custom third order Zernike basis stochastic parallel gradient descent algorithm that maximized the mean intensity of the acquired confocal image. The split-detection image was determined by dividing the intensity difference of the left and right channels by their sum.
Optical design of the system is shown in Figure 1. In a pilot experiment, the handheld probe was aligned and used in the simultaneous acquisition of confocal and split detection images of a model eye with paper retina at a speed of 6.8 frames per second, results of which are shown in Figure 2.
We have demonstrated the design of the first multimodal HAOSLO system and have tested it in a laboratory setup. Human imaging experiments are ongoing. This technology is expected to be impactful for imaging photoreceptors in adults, infants, and animal models of ophthalmic and neurodegenerative diseases.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Fig.1 Probe optical design. Red/blue rays depict illumination and collection paths, respectively. APD, avalanche photodiode; DM, deformable mirror; FM, fold mirror; L1–L10, lenses; LP, linear polarizer; MMF, multimode fiber; PBS, polarizing beam splitter; PM, polarization-maintaining; PMT, photomultiplier tube; QWP, quarter wave plate; SLD, superluminescent diode; SMF, single-mode fiber; VOA, variable optical attenuator.
Fig. 2 Images acquired from model eye in (a) confocal and (b) non-confocal channels. Scale bar is 250 µm.
This PDF is available to Subscribers Only