Laser & Optoelectronics Progress, Volume. 61, Issue 10, 1000003(2024)

Research Progress and Application of Confocal Scanning Laser Ophthalmoscope (Invited)

Xiadi Ye1...2, Jiangjie Huang1,2, Wen Kong1,2, Lina Xing1, Yi He1,2,*, and Guohua Shi12 |Show fewer author(s)
Author Affiliations
  • 1Jiangsu Key Laboratory of Medical Optics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, Jiangsu China
  • 2Division of Life Sciences and Medicine, School of Biomedical Engineering (Suzhou), University of Science and Technology of China, Suzhou 215163, Jiangsu China
  • show less
    Figures & Tables(15)
    Schematic diagram of field of view range for fundus imaging. (a) Lateral image of human eye from e-anatomy; (b) indocyanine green angiography image collected with Optos, in which four vortex veins can be seen
    Integrated corneal contact lens for ultra-wide field fundus imaging[16]
    Principle of Optos ultra-wide field CSLO
    Line scanning light path (scanning device is not shown)
    Wavefront shapes of ideal eye and normal eye[38]
    General fundus imaging AO system
    AOSLO optical path structure diagram[41]
    AOSLO imaging result[41]
    Human eye photoreceptor image obtained from AOSLO. (a) At 1° eccentricity of temporal side of fovea, bright spot in image is cone cells[51]; (b) at 10° eccentricity of fovea shows intact cones (large cells) with rod cells embedded in space[56]; (c) at inner segment of cone cells is shown at 10° eccentricity of temporal side of fovea, image shows inner segment of cone cells, inner segment of rod cells in gap cannot be distinguished due to its small size[51]
    Retinal vascular imaging. (a) AOSLO FA map of central foveal avascular area[96]; (b) contrast vascular perfusion map of central foveal avascular area movement[98]; (c) capillary diagram around retinal nerve papillary fossa obtained by offset pinhole AOSLO[74]; (d) capillary map at 5° eccentricity on nasal side of fovea obtained by dark field AOSLO[98]; (e) capillary map of same region in (d) obtained by split-detector AOSLO[98]
    AOSLO imaging results of various retinal tissue structures. (a) RPE image of healthy human eyes[52]; (b) tilted bundle structure is temporal NFL[106]; (c) vertical fine bundle structure is Henry fibers, while larger transverse inclined bundle structure with larger background is NFL[108]; (d) G-CaMP3 labeled fluorescence images of mouse GCs[111]; (e) G-CaMP5 labeled fluorescence images of GCs in macaques[112]; (f) HRA SLO video disc image developed by Heidelberg is overlaid with LC image obtained by AOSLO, and clear LC structure can be seen at arrow[113]
    • Table 1. Definition of field of view of fundus imaging[10]

      View table

      Table 1. Definition of field of view of fundus imaging[10]

      RegionField of viewAnatomic location
      Normal field of view0°‒50°Within retinal vascular arcades
      Wide angular field60°‒100°Edge of retinal vascular arcades to posterior edge of vortex vein ampulla
      Ultra wide angular field110°‒220°Anterior edge of vortex vein ampulla and beyond to pars plana
      Full field of view360°Entire retina
    • Table 2. Commercial non-contact ultra-wide field CSLO

      View table

      Table 2. Commercial non-contact ultra-wide field CSLO

      ProductMaximum field of view /(°)Imaging modeDevice photoDisplay of imaging effect
      NoteRF:red free;IR:infrared ray. Order of imaging effect images arranged from left to right corresponds one-to-one with order of imaging modes. All images are referenced from respective product online pages.
      Clarus133Color,red,green,blue,FAF,IR
      Mirante163Color,FA,FAF,ICGA,retro
      Spectralis102FA,ICGA,IR,FAF
      Optos200Pseudo color,RF,FAF,FA,ICGA,choroid
      CRO-PLUS160Color,RF,FAF,FA,ICGA,IR
    • Table 3. Technical improvement and achievement of AOSLO by major institute

      View table

      Table 3. Technical improvement and achievement of AOSLO by major institute

      InstituteImprovementAchievement
      University of Rochester(USA)

      1)Replaced confocal pinhole with annular pupils50.

      2)Developed split-detection mode51 and dark field mode52.

      3)Developed close-loop optical stabilization53 and fast registration54.

      4)Designed reflective afocal broadband AOSLO55

      1)Improved resolution.

      2)Imaged human cone photoreceptor inner segment and retinal pigment epithelium without label.

      3)Solved problem of high-resolution retinal image blurring caused by nystagmus.

      4)Reduced astigmatism of pupil and retinal conjugate surfaces simultaneously.

      5)First obtained human rod cell image56and single neuron image in ganglion cell layer57

      University of California,Berkeley(USA)

      1)Designed compact AOSLO based on microelectromechanical DM58.

      2)Developed synchronous laser modulation technology and retinal stability tracking technology59-63.

      3)Developed motion contrast imaging technology64.

      4)Designed scheme of versatile multi-detector65 and multi-wavelength imaging66,and further design wide convergence,multi-spectral AOSLO67

      1)Reduced device volume.

      2)Delivered a highly stable and aberration corrected stimulation to a single retinal cone cell,and simultaneously reduce influence of nystagmus so that expanded high-resolution imaging field.

      3)Achieved non-invasive capillary imaging and flow velocity measurements without any contrast media68.

      4)Expanded imaging channel,and achieve multi-channels aberration corrected simultaneously.

      5)Studied effects of fixational tremor on retinal image69-70

      University of Indiana(USA)

      1)Combined wide field SLO with AOSLO and further integrate71-73.

      2)Developed off-set aperture mode74-75.

      3)Developed spatiotemporal scanning mode with vertical scanning stopped76-77.

      4)Developed high speed polarimeter based on AOSLO78-79.

      5)Developed dual-channel scanning mode80.

      6)Replaced dot scanning mode with line scanning mode81

      1)Reduced influence of nystagmus,and location of high-resolution imaging can be obtained,so it is possible to achieve repeated imaging of the same area.

      2)Achieved fine structural imaging of vascular wall.

      3)Achieved fast measurement of retinal blood flow.

      4)Reduced calculation error of polarization caused by nystagmus,and use polarization characteristics to improve the contrast of retinal structure.

      5)Improved frame rate without increasing system complexity.

      6)Extremely reduced influence of nystagmus and improve frame rate.

      7)Template free eye motion correction82

      Chinese Academy of Sciences Institute of Optics and Electronics(China)

      1)Replaced confocal pinhole with specially designed pupil filter47.

      2)Introduced KLT-SIFT algorithm in image tracking83-84 and develop image auto-montage technology based on algorithm85.

      3)Designed bimorph DM based compact AOSLO86-87

      1)Improved resolution.

      2)Reduced image distortion caused by nystagmus and seam artifacts.

      3)Improved correction stroke and accuracy.

      4)First achieved measurement of blood oxygen saturation for small blood vessels below 50 μm45

    • Table 4. Method for increasing field of view of high-resolution fundus imaging

      View table

      Table 4. Method for increasing field of view of high-resolution fundus imaging

      MethodDisadvantageField of viewAuthor/Product
      Dual-conjugate adaptive opticsAs field of view increase,complexity of system will definitely increase4°×4°Laslandes88
      Reduce pupil diameterReducing pupil size will decrease lateral resolution4°×4°Imagine Eyes-rtx1(AOFIO)
      Correct aberrations in multiple fields separatelyAs field of view increase,imaging time also increase3°×5°Physic Science Inc-CAORI81
    Tools

    Get Citation

    Copy Citation Text

    Xiadi Ye, Jiangjie Huang, Wen Kong, Lina Xing, Yi He, Guohua Shi. Research Progress and Application of Confocal Scanning Laser Ophthalmoscope (Invited)[J]. Laser & Optoelectronics Progress, 2024, 61(10): 1000003

    Download Citation

    EndNote(RIS)BibTexPlain Text
    Save article for my favorites
    Paper Information

    Category: Reviews

    Received: Jan. 3, 2024

    Accepted: Jan. 24, 2024

    Published Online: May. 9, 2024

    The Author Email: He Yi (heyi@sibet.ac.cn)

    DOI:10.3788/LOP240437

    CSTR:32186.14.LOP240437

    Topics