Summary
Brown kiwis are an endangered species of nocturnal, flightless birds which are native to New Zealand. The resting focus of two specimens has previously been studied by retinoscopy in a zoo while the birds were restrained by their keeper (Sivak and Howland 1987). Those birds appeared to be hyperopic (farsighted) by 2–7 D. In this study, examination with infrared photorefraction of the focusing of two unrestrained, feeding birds showed that they could focus objects at infinity and objects in their immediate environment and that they had modest powers of accommodation. Measurements on two 6 month old kiwi chicks showed their corneal radius of curvature to be between 2.90 and 3.00 mm (117 D and 101 D in power).
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Diamond J (1990) Bob Dylan and Moas' ghosts. Natural History 10:26–31
Glickstein M, Millodot M (1970) Retinoscopy and eye size. Science 168:605–612
Howland HC (1985) Optics of photoretinoscopy: Results from ray tracing. Am J Optom Physiol Optics 62:621–625
Howland HC, Howland B (1974) Photorefraction: a technique for the study of refractive state at a distance. J Opt Soc Am 64:240–249
Howland HC, Sayles N (1984) Photorefractive measurements of astigmatism in infants and young children. Invest Ophthalmol Visual Sci 25:93–102
Nilsson S (1983) Autonomic nerve function in the vertebrates. Springer, Berlin Heidelberg New York, pp 30–34, 196–197
Peat N (1990) The incredible kiwi. Random Century, Albany, NZ
Schaeffel F, Howland HC (1987) Corneal accommodation in chick and pigeon. J Comp Physiol A 160:375–384
Schaeffel F, Howland HC (1988) Visual optics of normal and ametropic chickens. Clin Vision Sci 3:83–98
Schaeffel F, Howland HC, Farkas L (1986) Natural accommodation in the growing chicken. Vision Res 26:1977–1993
Schaeffel F, Farkas L, Howland HC (1987) Infrared photoretinoscope. Appl Optics 26:1505–1509
Sivak JG, Howland HC (1987) Refractive state of the eye of the brown kiwi (Apteryx australis). Can J Zool 65:2833–2835
Walls GL (1942) The vertebrate eye and its adaptive radiation. Cranbrook Institute of Science, Bloomfield Hills, MI, pp 281, 650
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Howland, H.C., Howland, M. & Schmid, K.L. Focusing and accommodation in the brown kiwi (Apteryx australis). J Comp Physiol A 170, 687–689 (1992). https://doi.org/10.1007/BF00198978
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00198978