The unique organization of the corneal stromal collagen is responsible for mechanical strength and optical clarity of the eye. However, factors and reasons on formation of the corneal stroma is still not fully understood. Second-harmonic generation (SHG) is a nonlinear second order optical process occurring in noncentrosymmetric systems with a large hyperpolarizability. Through the combination of the second harmonic generation (SHG) microcopy and optimized Fourier-transform analysis, mature chicken corneas are investigated to probe the depth-dependent collagen organization of the corneal stroma. Our results show that the anterior stroma behaves like a fan-like distribution of successively and counterclockwisely rotated fibrous lamellae for paired corneas from the same chicken. However, the posterior stroma maintains a non-rotating pattern while increasing in depth. Surprisingly, the thickness of the anterior stroma remains almost constant throughout the temporal-nasal direction, but the posterior stroma does not behave the same. Through quantitative analysis, the natural transition of the anterior and posterior stroma is also determined. These findings enhance our understanding of the collagen-rich tissue in the chicken cornea model. Moreover, the Fourier-transformbased modality, in combination with SHG microscopy, serves as a promising tool to determine collagen alignment in embryonic development, tissue engineering and corneal diseases.

Date Published: 8 February 2017
PDF: 4 pages
Proc. SPIE 10045, Ophthalmic Technologies XXVII, 100451U (8 February 2017); doi: 10.1117/12.2254942

Published in SPIE Proceedings Vol. 10045:
Ophthalmic Technologies XXVII
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)