Objective measures of retinal thickness changes over time during macular surgery using microscope-integrated optical coherence tomography

Abstract

Purpose : Macular surgery lacks objective measures to summarize the retinal impact of surgical tools for case comparisons and clinical trials. Our goal is to develop a method to quantify and analyze retinal thickness throughout macular surgery maneuvers using intraoperative microscope-integrated optical coherence tomography (MIOCT).

Methods : For this development, we used MIOCT images at 7 volumes/second, captured with an investigational device under IRB protocol during the macular portion of vitreoretinal surgery in patients with epiretinal membrane or macular hole without interrupting the procedure. We extracted site-specific retinal thickness measurements via our custom automated retinal segmentation software, to delineate the surgical tool and inner/outer retinal margins. Volumes were registered using vascular structures and processed for site-specific thicknesses across the period of instrument engagement with retina.

Results : We succeeded in semi-automated processing of MIOCT volumes that include retinal tool tips, as demonstrated in Fig 1A. We extracted and documented site-specific retinal thicknesses and how they changed over time and in relation to the surgical tool (loop or forceps). This analysis resulted in a summary for site-specific retinal thickness of change between time points (e.g. T₀ [baseline] vs T_x, Fig 1B), and cumulative changes over a defined time period (e.g. a full maneuver).

Conclusions : Retinal thickness changes over time can be extracted from MIOCT data of macular surgery. Thickness information and cumulative change can be summarized and visualized in different graphic formats. This data will be useful for rigorous analysis of intraoperative retinal impact as well as structural and functional outcomes between techniques, tools and/or surgeons.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Fig 1. A: The retina view (SVP, first row) and retinal thickness maps (second row; scale: 150 to 600 μ) at baseline (T₀) and at different time points (T_x, T_y, T_z) extracted from MIOCT during surgery. B: The retinal thickness change at each location was shown in red (elevation) or blue (depression) (scale: -100 to 100 μ).