Abstract
Purpose :
To analyze intraoperative OCT (iOCT) findings during subretinal gene therapy.
Methods :
A retrospective, observational, review of subretinal gene therapy surgeries was conducted at Casey Eye Institute-Oregon Health & Science University from July 2017 to July 2018. All surgeries were performed by the same surgeon. One-step subretinal bleb or pre-bleb, and manual or pneumatic-pedal assisted delivery techniques were used, depending on the surgical protocol and/or surgeon preference. All iOCT images were acquired by an assistant retina surgeon with previous experience in using the iOCT system. High definition images in grey or color scale were recorded. Images were later reviewed by the surgeon and two independent retinal specialists. Sharp needle tip (SNT) or blunted needle tip (BNT) and their interaction with neurosensory retina were evaluated. Presence of subretinal air bubbles, visible opened retinotomy, and medication reflux were also correlated and analyzed.
Results :
Nineteen of twenty-one eyes were included. Of the two excluded eyes, subretinal bleb creation was unsuccessful in one and technical issues prevented OCT image acquisition in the other. Mean age was 41.34 years (range 16 - 68) with eleven men (58%) and eight women (42%). Immediately before injection, needle indention/penetration of the neurosensory retina with temporary indentation of the RPE and choroid was evident in 16 (84%) of the 19 eyes with iOCT images. Complete RPE indentation was needed with BNT use compared to SNT (p=0.0114). An open retinotomy was identified in 14 (74%) of 19 eyes at the conclusion of bleb injection and was more commonly associated with SNT (p=0.0108). Subretinal air bubbles, characterized by a double hypereflective sign, were present in 10 cases (53%) and seven were found to occlude the inner aspect of the retinotomy. Medication reflux from the bleb into the vitreous cavity was visualized in two cases (11%). There was no statistically significant correlation between presence of reflux, open retinotomy, and the presence of air bubbles.
Conclusions :
iOCT provides valuable real-time feedback of cross-sectional retinal anatomy during subretinal gene therapy surgeries. Further retrospective analyses of iOCT findings during subretinal procedures are likely to help refine our surgical technique.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.