Retinal safety evaluation of photoacoustic microscopy. (January 2021)

• Record Type: Journal Article
• Authors: Li, Yanxiu; Zhang, Wei; Nguyen, Van Phuc; Khan, Naheed Wali; Xia, Xiaobo; Wang, Xueding; Paulus, Yannis M.
• Is Part Of: Experimental eye research. Volume 202(2021)
• Publication Date: 2021-01
• Subjects: Photoacoustic microscopy -- Retinal imaging -- Safety evaluation -- ERG; Ophthalmology -- Periodicals; Eye -- Periodicals; Œil -- Périodiques; Ophthalmology; Periodicals; Electronic journals; 612.8405
• DOI: 10.1016/j.exer.2020.108368
• Languages: English
• ISSNs: 0014-4835

Abstract

Abstract : Photoacoustic microscopy (PAM) has significant potential as a promising diagnostic method for eye diseases and can provide anatomic and functional information of the retinal and choroidal vasculature. However, there are no FDA-approved PAM systems for ophthalmic imaging. In this study, a comprehensive safety evaluation was performed to evaluate the safety of PAM retinal imaging and whether PAM causes damage to retinal structure or function in rabbit eyes. 12 Dutch-Belted pigmented rabbits received photoacoustic imaging to 57% of the retinal surface area with a laser energy of 5% of the ANSI safety limit for five consecutive days and followed before imaging and 3 days, 1, 2, 3, and 4 weeks post imaging. Retinal morphologic analyses using slit lamp examination, fundus photography, red free, FA, FAF, ICGA, and OCT showed no retinal hemorrhage, edema, detachment, vascular abnormalities, or pigmentary abnormalities in the retina or choroid after PAM imaging. Full-field ERG analysis showed no significant difference in scotopic or photopic a- and b-wave amplitudes or implicit times between the control and experimental eyes over time (n = 6, P values > 0.05). Retinal ultrastructural evaluation using TEM showed normal structure of organelles and nuclei, and no significant loss of cells after PAM. TUNEL assay showed no evidence of cells apoptosis in retina. Retinal histopathology indicated that the architecture and thickness of the retinal layers was well preserved in all experimental eyes. A positive control at 500% of the ANSI limit demonstrated significant damage. The comprehensive retinal safety evaluation demonstrated no damage to retinal structure or function for 4 weeks after PAM imaging in rabbits. Highlights: ● Photoacoustic microscopy (PAM) is a novel biomedical imaging technology which can image the retinal and choroidal vasculature with high resolution, yet there are no FDA-approved PAM systems to perform ophthalmic imaging. ● PAM can achieve good quality imaging in human-sized rabbit eyes with a laser fluence at only 1% of the ANSI safety limit. ● Comprehensive safety evaluation including slit lamp examination, full-field ERG, fundus photography, red free, FA, FAF, ICGA, OCT, TEM, TUNEL, histology, and immunohistochemistry demonstrated high quality PAM imaging of the rabbit eye with no evidence of any damage to retinal structure or function for 4 weeks after PAM imaging in rabbit eyes.