Eye Size at Birth in Prosimian Primates: Life History Correlates and Growth Patterns

BACKGROUND: Primates have large eyes relative to head size, which profoundly influence the ontogenetic emergence of facial form. However, growth of the primate eye is only understood in a narrow taxonomic perspective, with information biased toward anthropoids.\ud \ud METHODOLOGY/PRINCIPAL FINDINGS: We measured eye and bony orbit size in perinatal prosimian primates (17 strepsirrhine taxa and Tarsius syrichta) to infer the extent of prenatal as compared to postnatal eye growth. In addition, multiple linear regression was used to detect relationships of relative eye and orbit diameter to life history variables. ANOVA was used to determine if eye size differed according to activity pattern. In most of the species, eye diameter at birth measures more than half of that for adults. Two exceptions include Nycticebus and Tarsius, in which more than half of eye diameter growth occurs postnatally. Ratios of neonate/adult eye and orbit diameters indicate prenatal growth of the eye is actually more rapid than that of the orbit. For example, mean neonatal transverse eye diameter is 57.5% of the adult value (excluding Nycticebus and Tarsius), compared to 50.8% for orbital diameter. If Nycticebus is excluded, relative gestation age has a significant positive correlation with relative eye diameter in strepsirrhines, explaining 59% of the variance in relative transverse eye diameter. No significant differences were found among species with different activity patterns.\ud \ud CONCLUSIONS/SIGNIFICANCE: The primate developmental strategy of relatively long gestations is probably tied to an extended period of neural development, and this principle appears to apply to eye growth as well. Our findings indicate that growth rates of the eye and bony orbit are disassociated, with eyes growing faster prenatally, and the growth rate of the bony orbit exceeding that of the eyes after birth. Some well-documented patterns of orbital morphology in adult primates, such as the enlarged orbits of nocturnal species, mainly emerge during postnatal development.\ud \u

A- and B-modes echobiometry in cataractous and noncataractous eyes of English Cocker Spaniel dogs Ecobiometria nos modos A e B, de olhos de cães da raça Cocker Spaniel Inglês com e sem catarata

A- and B-modes ultrasonographic changes in the thickness of various structures of the eyeball in male and female English Cocker Spaniel dogs with and without nondiabetic cataracts were evaluated. Sixteen dogs with cataracts (32 eyes) and seven normal dogs (14 eyes) older than eight years were selected. A- and B-modes ultrasonography was performed with a 10MHz transducer. Data was statistically evaluated by one way ANOVA. Mean and standard deviations of various ocular structures for dogs with and without cataracts were, respectively, anterior chamber: 3.041±0.828mm, 3.373±1.040mm; lens: 6.817±1.117mm, 7.062±0.477mm; vitreous: 10.056±0.754mm, 9.523±0.705mm; and axial length: 19.909±1.103mm, 19.958±1.050mm. Ocular measurements between right and left eyes, males and females, as well as in eyes with and without cataract were not different (P>0.05).<br>Avaliaram-se as alterações na dimensão de estruturas do bulbo do olho de cães da raça Cocker Spaniel Inglês, machos e fêmeas, com ou sem catarata não diabética. Dezesseis animais com catarata (n = 32 olhos) com idade acima de oito anos e um grupo-controle, composto por sete cães, com idades também acima de oito anos, sem catarata (n = 14 olhos) compuseram a pesquisa. Realizou-se ultrassonografia transcorneana nos modos A e B com transdutor de 10MHz. Os dados foram submetidos à análise de variância e ao teste Tukey para comparação de médias. O comprimento axial do bulbo do olho dos animais com catarata e dos animais do grupo-controle foram, respectivamente, 19,909±1,103mm e 19,958±1,050mm. Para a câmara anterior, encontraram-se 3,041±0,828mm; 3,373±1,040mm, respectivamente. Para o diâmetro lenticular, os valores foram 6,817±1,117mm e 7,062±0,477mm, respectivamente, e para o segmento posterior, 10,056±0,754mm e 9,523±0,705mm, respectivamente. Não se encontraram diferenças significativas entre olhos com catarata e do grupo-controle, tampouco entre machos e fêmeas com e sem catarata, nem entre olhos direitos e esquerdos (P>0,05)