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Retinal ganglion cell distribution and visual acuity in alpacas ( V icugna pacos )
Author(s) -
Wang HsiaoHui,
Gallagher Shan K.,
Byers Stacey R.,
Madl James E.,
Gionfriddo Juliet R.
Publication year - 2015
Publication title -
veterinary ophthalmology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.594
H-Index - 50
eISSN - 1463-5224
pISSN - 1463-5216
DOI - 10.1111/vop.12131
Subject(s) - retina , retinal , retinal ganglion cell , visual acuity , optic nerve , anatomy , ophthalmology , meridian (astronomy) , streak , biology , ganglion , giant retinal ganglion cells , medicine , optics , neuroscience , physics , astronomy
Objective To investigate the distribution of retinal ganglion cells ( RGC s) and visual acuity in alpacas ( Vicugna pacos ) through B rn‐3a immunofluorescent labeling. Procedures Five eyes from four healthy alpacas with normal ophthalmic examination findings were included in the study. The axial length of the globes was measured before fixation. All five retinas were treated with B rn‐3a antibodies to label RGC s. Images taken with a fluorescent microscope were used for RGC counting. RGC density maps were reconstructed by computer software. Visual acuity was estimated based on the results of peak RGC density and ocular anatomical parameters. Results The reconstructed retinal maps from B rn‐3a labeling showed a horizontal streak across the retinal meridian superior to the optic nerve head with a temporal, upward extension. The highest RGC densities were in the temporal retinas. The maximal visual acuity was located in the temporal retina and was estimated to range between 12.5 and 13.4 cycles per degree. Conclusions Alpacas have a horizontal streak across the retinal meridian superior to the optic disk with a temporal, upward extension based on the Brn‐3a labeling of RGC s. The maximal visual acuity was located in the temporal retina. The reconstructed retinal maps indicate the RGC topography of alpacas is similar to that of other herbivores, but is different from that of dromedary camels.