Cheetah (Acinonyx jubatus)- Data, Pictures & Videos

[Acinonyx sp.]

OCULAR ABNORMALITIES OF CHEETAHS EXAMINED AT AFRICAT 

Introduction 

Over the past years a number of cheetahs in Namibia have been examined ophthalmologically. Equipment used during this examination included a slit lamp biomicroscope, indirect and direct ophthalmoscope, Schiotz tonometer, fluorescein stain and gonioscopy lens. The animals were anaesthetised for the annual health checks at Africat in Namibia, or were examined at the time of presentation for blindness. A high incidence of ocular trauma ranging from mild scarring of the lids and/or cornea, through to mature cataracts, severe endophthalmitis and phthisis bulbi was found. It is theorised that this is as a result of the cheetah being forced to hunt in bushencroached areas – a habitat not ideally suited to the hunting methods of the cheetah. Blindness or severe visual impairment spells death for a wild cheetah, and could thus impact greatly on the sustainability of the wild cheetah population of Namibia. In 1997, four cheetahs were presented for ocular examination and assessment of visual status as these animals were presumed to be blind. Two were adult animals found in the wild in poor physical health and on the brink of death (one old male of unknown age, and 1one adult female, also of unknown age, with three six-week old cubs at foot), while the other two were young animals approximately one year old that had been born in captivity and hand raised. The two young animals were found to have bilateral mature cataracts with no signs of any other ocular defects. These cataracts were assumed to be either of congenital or nutritional origin. The adult animals were found to have severe signs of ocular trauma, including lid and nictitans scars, penetrating scar tracts of the cornea, severe synechiation and mature cataracts. In the female, foreign bodies were found in the cornea of one eye (two thorn tips), with the presence of severe uveitis in this eye. These animals, following appropriate care and treatment, all underwent successful cataract extraction surgery by phacoemulsification lentectomy technique. These findings prompted an investigation into the cause of the cataracts in adult wild-caught animals to try to ascertain whether the ocular trauma was secondary to the visual deficits present as a result of the cataracts. 


Conclusion 
It was shown beyond doubt in this study that there is a high incidence of ocular trauma in wild free-living cheetahs in Namibia. This trauma was as a result of thorn or foliage damage to the lids, nictitans and cornea - the latter being the most significant, as there was a high incidence of evidence of penetrating corneal injury leading to either uveitis with secondary cataract formation, or direct damage of the anterior capsule of the lens with posterior synechiae formation and cataracts. It is of concern that the incidence, severity and consequences of ocular trauma is of such a nature that it could impact severely on the longevity of a cheetah in a bush-encroached environment. As similar incidences of ocular trauma are not found in lion and leopard populations in the preliminary studies done, and because these cats generally live in thicker bush habitat than the cheetah, it is surmised that factors are present which are adversely affecting the health of the cheetah’s eyes in the wild. It is proposed from this study that the anatomy of the cheetah’s skull, its large forward-facing exposed eyes, its body designed for speed rather than stealth hunting and its habit of hunting predominantly during the day, make it the ideal hunter for open grassland or plains. As the cheetah in Namibia is being restricted to overgrazed, bush-encroached areas, it is forced to hunt in this type of vegetation, leading to the high incidence of ocular trauma encountered. Reply