Comparative ocular anatomy of the western lowland gorilla.
ABSTRACT To examine the lowland gorilla (Gorilla gorilla gorilla) eye and determine similarities to and differences between the mountain gorilla (Gorilla gorilla beringei) and the human eye. In addition, we compare our findings of G. g. gorilla to previous reports on the eye of this subspecies.
A 13-year-old deceased male lowland gorilla and a 34-year-old deceased female lowland gorilla were included in the study. Gross and microscopic examinations of the formalin-fixed right eyeball of each gorilla were carried out.
Globe dimensions of G. g. gorilla were similar to G. g. beringei and to humans. The limbal conjunctival epithelium and the choroid were densely pigmented. However, the distribution of the conjunctival pigment ring was different to that of G. g. beringei and the melanocytes of the choroid were unusually round. There were deep crypts in the anterior border layer of the iris, and the epithelium of the pars plana was uniquely irregular. Vertical corneal diameter was observed to be equal or greater than horizontal diameter in G. g. gorilla, which is in contrast to humans and to previous findings for G. g. beringei. Corneal thickness was closer to that of humans than to G. g. beringei. Posterior lens capsule thickness was noticeably greater than that of humans.
Although some variation between the ocular anatomy of G. g. gorilla and G. g. beringei does exist, the gross and microscopic findings closely resemble each other in these two subspecies. In addition, the eye of Gorilla appears remarkably similar to the human eye. However, comparison of measurements with those in humans is somewhat limited because formalin-fixation can introduce tissue shrinkage and artifact.
- SourceAvailable from: Simona di pietroJournal of Applied Ichthyology 04/2015; 31(2). DOI:10.1111/jai.12678 · 0.90 Impact Factor
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ABSTRACT: Human eye morphology is considered unique among the primates in that humans possess larger width/height ratios (WHR), expose a greater amount of visible sclera (SSI; width of exposed eyeball/width of visible iris), and critically, have a white sclera due to a lack of pigmentation. White sclera in humans amplifies gaze direction, whereas the all-dark eyes of apes are hypothesized to conceal gaze from others. This study examines WHR and SSI in humans (N = 13) and gorillas (N = 85) engaged in direct and averted gazes and introduces a qualitative assessment of sclera color to evaluate variations in sclera pigmentation. The results confirm previous findings that humans possess a larger WHR than gorillas but indicate that humans and gorillas display similar amounts of visible sclera. Additionally, 72% (N = 124) of gorilla eyes in this sample deviated from the assumed all-dark eye condition. This questions whether gaze camouflage is the primary function of darkened sclera in non-human primates or whether other functional roles can be ascribed to the sclera, light or dark. We argue that white sclera evolved to amplify direct gazes in humans, which would have played a significant role in the development of ostensive communication, which is communication that both shows something and shows the intention to show something. We conclude that the horizontal elongation of the human eye, rather than sclera color, more reliably distinguishes human from great ape eyes, represented here by gorillas. Am. J. Primatol. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.American Journal of Primatology 04/2015; DOI:10.1002/ajp.22411 · 2.14 Impact Factor
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ABSTRACT: PurposeThe purpose of this study was to establish reference values for diagnostic ophthalmic tests in sambar deer (Rusa unicolor) as well as to describe the most relevant features of the bony orbital anatomy and ocular histology.Method Twenty healthy animals, free living in a forest reserve, that were captured for clinical evaluation as part of a health survey were evaluated. Schirmer tear test-1 (STT1), conjunctival microbiota, intraocular pressure (IOP), conjunctival cytology, anatomy of the bony orbit, and ocular histology were studied.ResultsMean ± SD STT1 and IOP values were 18.8 ± 4.7 mm and 11.4 ± 2.8 mmHg, respectively. IOP was significantly higher in adult (4–8 years) animals (P = 0.04). Bacterial growth was present in 100% of the samples, with a prevalence for Staphylococcus sp. and Bacillus sp. The conjunctival cytology revealed predominance of columnar epithelial cells with mild pigmentation. The sambar deer orbit is completely encompassed by bone. The ocular histology was very similar to most mammalians.Conclusions The findings in this study will be useful in the diagnosis of ocular diseases in Rusa unicolor.Veterinary Ophthalmology 10/2014; 18. DOI:10.1111/vop.12221 · 1.09 Impact Factor