The novel model: Experimental optical coherence tomography–guided anterior segment imaging chick embryo model

ABSTRACT

Purpose: The aim of this study was to present an experimental optical coherence tomography (OCT)–guided anterior segment (AS) imaging chick embryo model. Through this model, we aimed to reveal similarities and differences between human cornea, AS tissues, and chick embryo tissues by quantitative image analysis. Methods: Ex vivo, the chick embryos' globes were determined by detailed AS camera of spectral-domain (SD)-OCT in 10 fertilized specific pathogen-free eggs on the 20th day. Quantitative image analysis of anterior chamber tissues was performed with SD-OCT in detail. After imaging, cross sections of the chick embryo globes containing cornea with anterior chamber were histologically examined and compared with human tissues. The similarities of our model with data in the human cornea and AS studies in the literature were compared. Results: SD-OCT imaging was able to successfully delineate the AS tissues of chick embryos such as the cornea, iris, lens, pupil, conjunctiva, ciliary body, anterior chamber, and lens. Quantitative semi-automated measurements showed the following mean central corneal thickness 213.4 ± 7.05 ?m (197–223 ?m), mean anterior chamber depth 878.9 ± 41.74 (804–919 ?m), mean anterior chamber area 2.43 ± 0.16 mm2 (2.17–2.73 mm2), mean corneoscleral junction (limbal) thickness 322.8 ± 20.05 ?m (289–360 ?m), and mean iris thickness 230.4 ± 13.27 ?m (203–245 ?m). In addition, detailed histological comparisons of the AS tissues with human tissues were evaluated to be very similar. Conclusion: In conclusion, this chick embryo model mimics human tissues and it can be considered as a platform for the study of teratogen-induced malformations and AS dysgenesis during gestation of AS tissues. In addition, this study demonstrates the feasibility of SD-OCT in the quantitative assessment of AS structures in chick embryo model.