June 2020
Volume 61, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2020
Optical modelling and image dewarping procedures for quantitative measurements of subretinal microinjection volumes using intraoperative OCT
Author Affiliations & Notes
  • Jianwei David Li
    Biomedical Engineering, Duke University, North Carolina, United States
  • William Raynor
    Ophthalmology, Duke University Medical Center, North Carolina, United States
  • Ananth Sastry
    Ophthalmology, Duke University Medical Center, North Carolina, United States
  • Al-Hafeez Dhalla
    Biomedical Engineering, Duke University, North Carolina, United States
  • Christian Viehland
    Biomedical Engineering, Duke University, North Carolina, United States
  • Cynthia Toth
    Ophthalmology, Duke University Medical Center, North Carolina, United States
    Biomedical Engineering, Duke University, North Carolina, United States
  • Lejla Vajzovic
    Ophthalmology, Duke University Medical Center, North Carolina, United States
  • Joseph A Izatt
    Biomedical Engineering, Duke University, North Carolina, United States
    Ophthalmology, Duke University Medical Center, North Carolina, United States
  • Footnotes
    Commercial Relationships   Jianwei Li, None; William Raynor, None; Ananth Sastry, None; Al-Hafeez Dhalla, Beyeonics (C), Leica Microsystems (F), Leica Microsystems (P); Christian Viehland, None; Cynthia Toth, Alcon (F), EMMES (C), EMMES (R), Hemosonics (F); Lejla Vajzovic, Alcon (C), Orbit Biomedical (F), Orbit Biomedical (C); Joseph Izatt, Carl Zeiss Meditec (P), Carl Zeiss Meditec (R), Leica Microsystems (P), Leica Microsystems (R), St. Jude Medical (P), St. Jude Medical (R)
  • Footnotes
    Support  NIH U01EY028079, NIH P30 EY005722, Orbit Biomedical Research Grant
Investigative Ophthalmology & Visual Science June 2020, Vol.61, 3499. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Jianwei David Li, William Raynor, Ananth Sastry, Al-Hafeez Dhalla, Christian Viehland, Cynthia Toth, Lejla Vajzovic, Joseph A Izatt; Optical modelling and image dewarping procedures for quantitative measurements of subretinal microinjection volumes using intraoperative OCT. Invest. Ophthalmol. Vis. Sci. 2020;61(7):3499.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose : New genetic therapies are an increasingly relevant and effective form of treatment for a variety of retinal diseases, but these procedures are limited by the complexity of delivering the correct volume of therapeutics to the target location. Intraoperative OCT (iOCT) can show delivery location, but quantitative measurements are challenging because of distortions due to intraocular structures. We present a novel method to make quantitative measurements of subretinal features and dewarp retinal OCT scans.

Methods : An optical model (Fig 1) of the OCT system and novel experimental procedure allows us to characterize the behavior of an OCT scan in the eye and correct distorted retinal OCT images. This was tested using a custom swept-source iOCT system. The technique was calibrated by computing the volume of 1 mm diameter alumina ceramic spheres inserted into ex vivo porcine eyes.

To test microinjection quantification, a small entry bleb was injected into the subretinal space of 37 ex vivo porcine eyes using a suprachoroidal delivery system from Orbit Biomedical, an OCT volume was captured, the full therapeutic dose was delivered, and a final OCT volume was captured. An expert grader manually segmented the bleb regions. The volume of the entry and final blebs was computed, and the difference was the therapeutic volume. The delivery procedure was repeated outside the eye to establish a control volume.

Results : The measured sphere volumes were 0.847±0.041 mm3 (n=15) compared to the actual 0.524 mm3, resulting in a calibration factor of 0.619. The calculated therapeutic volume of subretinal injections was 54.8±12.3 μL (n=10) (Fig 2). The control volume was 66.4±2.46 μL (n=20).

Conclusions : OCT imaging is suitable for visualizing subsurface features and extracting quantitative measurements.

This is a 2020 ARVO Annual Meeting abstract.

 

Fig 1: OCT optical model. Distance microscope moves to image the retina (irrd), distance from IR card to OCT pivot point (irpd), reference arm length change (refd), and pivot-to-retina distance (prd) allow us to find scan lengths in the eye.

Fig 1: OCT optical model. Distance microscope moves to image the retina (irrd), distance from IR card to OCT pivot point (irpd), reference arm length change (refd), and pivot-to-retina distance (prd) allow us to find scan lengths in the eye.

 

Fig 2: Uncorrected (a,f) and corrected B-scan (c,h), uncorrected (b,g) and corrected volume render (d,i) and maximum intensity projection (MIP) (e,j) showing the initial entry (left column) and final bleb (right column). Microinjection needle (blue arrow), manual segmentation (red outlines) and B-scan position (green lines).

Fig 2: Uncorrected (a,f) and corrected B-scan (c,h), uncorrected (b,g) and corrected volume render (d,i) and maximum intensity projection (MIP) (e,j) showing the initial entry (left column) and final bleb (right column). Microinjection needle (blue arrow), manual segmentation (red outlines) and B-scan position (green lines).

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×