الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The dromedary camel is one of the most important domestic animals in the arid
and semi arid regions. Compared to other livestock, the dromedary camel is unique
for having an exceptional ability to survive and thrive under adverse climatic
conditions such as high ambient temperatures, low rainfall and scarcity of feed,
unbearable solar radiation and water scarcity, therefore, it offers an ideal animal for
animal production in arid and semi arid regions of the world. The eye of the camel
plays an important role in its survival in these arid zones. This study was initiated
to detail the major landmarks and the time course of the prenatal development of
the eye tunics in the dromedary camel; to analyze the dromedary camel’s visual
world through assessment the total number and topographic distribution of retinal
ganglion cells; and to survey the normal findings of ocular structures as displayed
in Ultrasonography (US), Computed Tomography (CT), and Magnetic Resonance
Imaging (MRI). Firstly, Serial histological sections of dromedary camel embryos
and fetuses were used for prenatal development of the eye tunics; age estimation
was made on the basis of gestational size, crown vertebral-rump length (CVRL),
which ranged from 1.2 cm to 110 cm. The eye of the dromedary camel developed
in a similar manner to that of the human and domestic animals eyes; the principal
differences were in the time of occurrence of certain developmental events,
pigmented peripheral cornea near the limbus, a remarkably thickened Descemet’s
membrane and pigmentation in the corneo-scleral junction, which represent an
adaptive modification in relation to a severe environment. Secondly, Left eyes
from 24 adult camels, 3-4 years old, were used for whole-mounts and retinal
collodion parasagital sections (confirmatory method). Furthermore, the visual
acuity histologically was estimated. The dromedary camel has about 407,000
RGCs. The topographic distribution of RGCs showed a well defined horizontal
visual streak with a dorsotemporal extension of higher cell density. The peak visual
acuity in the dromedary camel was 13.52 cycles/degree. Artiodactyls take always
precautions against predators. Therefore, the retina in artiodactyls has a visual
streak for a horizontal wide visual field. Thus, the visual streak found in the
dromedary camel is formed by common needs among artiodactyls. Thirdly, six
fetuses of five CVRL stages; 33.5, 54.5, 71, 74 and 84 cm and six adult fixed
eyeballs were used for comparative imaging. Complementary cross-sectional
imaging modalities of the eye: Ultrasonography (US), Computed Tomography
(CT), and Magnetic Resonance Imaging (MRI) were applied.