Development of the refractive state in eyes of ostrich chicks (Struthio camelus).
OBJECTIVE
To follow the development of the refractive error in the eyes of ostrich chicks from age 0 to day 37 after hatching.


METHODS
35 ostrich chicks.


METHODS
Spot retinoscopy was conducted to assess refractive error in ostrich chicks. Seventy eyes of 35 ostrich chicks were examined. Of these, 18 chicks were followed over time. At least 4 serial measurements (at 2- to 7- day intervals) were conducted in each of these chicks from day 1 to 37 after hatching. Seventeen additional chicks were examined on days 0, 3, 12, and 19 after hatching.


RESULTS
Ostrich chicks were myopic at hatching, with a mean +/- SD refractive error of -4.47 +/- 0.15 diopters (D). The refractive error rapidly decreased during the first week of life, and by day 7 after hatching, chicks were slightly hyperopic, with a mean refractive error of 0.42 +/- 0.12 D. After day 7, there were no significant differences in the mean refractive error.


CONCLUSIONS
The development of optics in the ostrich eye appears to be unique among animals and is characterized by myopia at hatching, rapid onset of emmetropia, and minimal variation in refractive error among chicks.
Ofri
R
R
Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel.
Millodot
S
S
Shimoni
R
R
Horowitz
I H
IH
Ashash
E
E
Millodot
M
M
D000818:Animals; D005123:Eye; D012029:Refraction, Ocular / Q000502:physiology*; D020310:Struthioniformes / Q000502:physiology*