Pre‐ and Postnatal Development of the Eye: A Species Comparison

Abstract

In this review paper, literature data on pre- and postnatal eye development are compared between humans and nonclinical species that are commonly used for human safety assessment, namely, mouse, rat, rabbit, dog, minipig, and nonhuman primates. Some new data on rat and minipig ocular development are also included. This compiled information can be helpful for species selection in juvenile toxicity studies or assist in the interpretation of (non)clinical data during pediatric drug development. Despite some differences in developmental windows and anatomical peculiarities, such as the lack of a fovea centralis in nonprimate species or the presence of a nictitating membrane in some nonclinical species, the functioning and development of the eye is strikingly similar between humans and other mammals. As such, all commonly used nonclinical species appear to be relatively good models for human eye development, although some practical constraints such as size may be a limiting factor. Birth Defects Research 109:1540-1567, 2017. © 2017 Wiley Periodicals, Inc.

Morphologic and electrophysiologic findings of retinal degeneration after intravitreal sodium iodate injection following vitrectomy in canines

“…In the present study, we analyzed retinal degeneration in canine eyes induced by the intravitreal injection of 1.0 or 1.2 mg of SI after vitrectomy. In our previous study, the mean axial length of the rabbit eyes was actually measured as 15.96 mm, while, in our present study, the mean axial length of the canine eyes was measured as 21.50 ± 0.42 mm, as similarly reported in prior literature 21,38 . Thus, the difference in axial lengths between rabbits and canines was about 1.4-fold; if converting to volume, the difference in volumes between the two was measured as about 2.74 times.…”

“…There has been no canine model with retinal degeneration induced by intravitreal drug injection to date. The advantage of canine models is the similarity in size of the canine eye to the human eye (an axial length of approximately 22 mm), in addition to the fact that canine models have a higher photoreceptor density compared with rodent models 21,22 .…”

A Transient Developmental Background Finding in the Retina Observed in Neonatal Dogs in Juvenile Toxicology Studies

“…Findings observed in animal species at a window of time when a given tissue is immature and still undergoing development may not be predictive of efficacy and toxicity in the same tissue which has reached maturation in humans. In nonprimate species used in toxicology studies, the eye is relatively immature at birth in comparison to that of the human (Van Cruchten et al 2017). At birth, the canine retina is more immature than the human retina and corresponds to a human retina at 3 to 4 months of gestation (Cook 2013).…”

Concise Review: Human Induced Pluripotent Stem Cell Models of Retinitis Pigmentosa

“…The accumulated knowledge of RP has largely relied on animal models (mainly rodents) in cases where gene variations observed in patients are faithfully mimicked in animals . In addition to differences in genetic background, rodents are nocturnal animals with a higher proportion of rods and lack fovea and cone‐rich regions . Moreover, the scientific community is trying to reduce the use of animals in research.…”