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Updated: Jul 25, 2026
Optimized Ex-ovo Culturing of Chick Embryos to Advanced Stages of Development
Published on: January 24, 2015
Development of the refractive state in eyes of ostrich chicks (Struthio camelus)
R Ofri1, S Millodot, R Shimoni
1Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel.
Insights
Ostrich chicks hatch with myopia but rapidly develop normal vision within a week. Refractive error stabilizes after seven days, indicating unique ocular development in these birds.
Area of Science:
- Ophthalmology
- Comparative Biology
- Animal Science
Background:
- Refractive error development in avian species is not well-documented.
- Understanding refractive error progression is crucial for avian eye health research.
Purpose of the Study:
- To track the changes in refractive error in ostrich chicks from hatching up to 37 days.
- To characterize the typical refractive development in young ostriches.
Main Methods:
- Spot retinoscopy was used to measure refractive error in 70 eyes of 35 ostrich chicks.
- Serial measurements were taken from day 1 to day 37 post-hatching in 18 chicks.
- 17 additional chicks were examined at specific time points (days 0, 3, 12, and 19).
Main Results:
- Ostrich chicks exhibited myopia at hatching (mean -4.47 D).
- A rapid shift towards hyperopia occurred within the first week, reaching 0.42 D by day 7.
- Refractive error remained stable with minimal variation after day 7.
Conclusions:
- Ostrich eye optics show a unique developmental pattern compared to other animals.
- Key characteristics include initial myopia, rapid emmetropization, and low refractive variability.
- This suggests a distinct biological mechanism for refractive development in ostriches.
Objective:
To follow the development of the refractive error in the eyes of ostrich chicks from age 0 to day 37 after hatching.
Animals:
35 ostrich chicks.
Procedures:
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.
