Purchase this article with an account.
Y. Garcia Sanchez, C. T. Torti, B. Povazay, W. Drexler, J. A. Guggenheim, J. T. Erichsen; Wavefront Analysis of Peripheral Vision Quality in the Pigeon Eye. Invest. Ophthalmol. Vis. Sci. 2009;50(13):6165.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Lateral eyed animals, such as the pigeon (Columba livia), have a potentially panoramic view of the world, but the actual quality of the peripheral retinal image in such animals is unknown. Adaptive optics provides a precise, objective means to measure the ocular aberrations corresponding to locations in the peripheral visual field. In the human eye, and many artificial optical systems, off-axis vision is dominated by defocus and astigmatism, as well as higher order aberrations. We hypothesised that the eye of the highly visual pigeon was at least partly corrected for wide-angle vision.
Using a Hartmann-Shack wavefront sensor, ocular aberrations were evaluated in 16 eyes of 8 birds. The head of the fully anesthetized pigeon was immobilised in a stereotaxic frame, which allowed rotation around the nodal point of the eye with a precision of ± 1°. Image quality could be measured up to 70° away from the central fovea both nasally and temporally. For all eccentricities, the Zernike coefficients were calculated up to 5th order and evaluated for a 4mm diameter pupil.
In terms of lower order aberrations (Fig 1), astigmatism showed a slight increase from the centre towards the periphery but remarkably did not exceed 0.25D on average. Refractive error (defocus) was almost constant at around -1D. For central vision (c. 80° from the beak), the retinoscopic values for defocus and astigmatism were compared with the Hartman-Shack measurements and showed good agreement. Including all Zernike coefficients (Fig 1), the total aberration of the eye remained small and virtually constant over the entire 130° range measured.
This PDF is available to Subscribers Only