Abstract
Purpose :
To obtain OCT recordings of human retinas during robotic vitreo-retinal surgery using an instrument integrated OCT-based distance sensor. To evaluate OCT signal quality and characteristics of the scans. To compare image quality and thickness measurements with standard pre-operative OCT scans
Methods :
A first in-human clinical evaluation of a robotic instrument with real-time OCT-based distance sensor, was performed at the Rotterdam Eye Hospital. Following standard vitrectomy, the sensor was inserted into the vitreous while connected to the PRECEYES surgical system. Signal to noise ratio (SNR) was used to define the quality of the signal at various angles to the retina and different distances of the probe from the retina.
Movies recorded from surgeries were synchronized with the OCT signal from the robot. The pre-operative OCT scans (Canon OCT – HS100) were superimposed to the movies. Spots of the retina scanned by both instruments were used to compare image quality and retinal thickness. Quality was defined by recognizable retinal layers; thickness by the measure from the ILM to the RPE
Results :
5 patients were included. OCT images were obtained from all patients. Retinal movement was recorded as 8-24 μm in patient 1,2,4,5, and 200 μm in patient 3. SNR was always adequate at all distances from the retina and at all angles.
In four patients we found at least two spots of the retina scanned with both the pre-operative OCT and the surgical instrument. In these patients, a series of inner hyperreflective bands (from RNFL to OPL), a large hypo reflective outer band (ONL) and a thin hyperreflective outermost band (IS/OS junction to RPE) were identifiable. The mean retinal thickness difference obtained by the two instruments in the same spot was 16.11 μm (SD ± 14.53 μm)
Conclusions :
OCT recordings of the human retina with a robot- integrated sensor is feasible. OCT scans can record movements from the patients, as heartbeat (amplitude of 8 μm) and breathing (10-24 μm, patient 3 was snoring). It allowed us to obtain constant and reliable OCT acquisitions of a good quality with discernible retinal layers. The retinal thickness of a certain spot can be appropriately measured with a standard pre-operative OCT assessment. In terms of future clinical application these features will allow for example, to perfectly plan a sub-retinal delivery of gene therapy using a robot-controlled needle with OCT distance sensors.
This is a 2020 ARVO Annual Meeting abstract.