Dimensional Growth of the Rabbit Eye

Abstract

The rabbit eye has been used experimentally in research in vision and ophthalmology. However, there is little information about postnatal growth. The purpose of this study was to determine growth patterns of the rabbit globe from birth to young adult status focusing in particular on the fibrous outer tunic of the globe, the sclera. Eyes of both sexes of New Zealand White rabbits were examined on postnatal days 1, 7, 14, 28, 42 and 56. Axial length, equatorial diameter and corneal diameter were measured using a digital caliper. Plastic-embedded tissue was used to quantify scleral thickness and cellular density at anterior, equatorial and posterior sites. Axial length increased 230% between postnatal days 1 and 56. The rate of growth was not linear and revealed two peaks. The first peak occurred between postnatal days 1–7, and the second between days 14–28. Eye opening occurred on days 9–11. Sex differences were seen, with the male eye being larger (p = 0.00001). Surface area measurements of sclera and cornea revealed that the sclera occupies approximately 5/6 of the outer surface of the globe and the cornea 1/6. Scleral thickness increased from day 1 to day 42 (70–155 µm at the equator) while fibroblast density was found to decrease (0.32 to 0.05 cells/µm²). The results suggested that eye opening precedes a unique increase in the rate of eye growth and visual processes may be playing a role in modulating the growth pattern between days 14 and 28.

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

“…Opening of the eyelids occurs at PND9 to 11 (Barathi et al, ). The eyes of a newborn rabbit are rotation ellipsoids with a horizontal to vertical axis of 1.3, whereas this is 1.1 in the adult (Reichenbach et al, ), which does not occur in humans.…”

Assessment of Subconjunctival and Intrascleral Drug Delivery to the Posterior Segment Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

“…Adapting a methodology for the calculation of the scleral surface area, 22 the surface area of the suprachoroid was approximated as 8 cm 2 . The suprachoroidal space is included within a volume of 8 cm 2 multiplied by the pixel width (0.184 mm).…”

Rabbit Models of Contact Lens–Associated Corneal Hypoxia: A Review of the Literature

“…Three studies indicated the exclusive use of male rabbits, [13][14][15] whereas the balance of studies used a combination of male and female rabbits. There is limited evidence of an anatomic basis for the exclusive use of male rabbits, 16 but perhaps more important is the confirmation of uniform corneal diameter in study animals. When a 14-mm contact lens is used, the potential for the lens to overlap significantly onto the limbus may be relevant.…”

“…Numerous structural and biochemical changes occurring in the rabbit cornea during postnatal development would complicate the use of adolescent animals. 3,16 …”