Bilateral lens luxation and intracapsular lens extractions in a Matshchie's tree kangaroo

OCULAR ANATOMY AND PATHOLOGY IN LUMHOLTZ'S TREE-KANGAROO (DENDROLAGUS LUMHOLTZI)

Lumholtz's tree-kangaroo (Dendrolagus lumholtzi) is one of two species of tree-kangaroos found in Queensland, Australia. There is little information about ocular anatomy and pathology in any species of tree-kangaroo, and there are claims of blindness from unknown causes in free-ranging Lumholtz's tree-kangaroos. This study investigated ocular anatomy and pathology in 80 individuals, using examination of 31 live animals and histopathologic examination of eyes from 49 carcasses. Tree-kangaroos were found to have a typical vertebrate eye with immuno-histochemical evidence for dichromatic color vision. Only 5.4% of animals had evidence of pathology from traumatic injury, infection, or a variety of nonspecific lesions. Toxoplasmosis was implicated in ocular lesions in three animals. This study did not find evidence of widespread blindness in free-ranging animals nor evidence of toxic optic neuropathy. Examinations of live animals highlighted the need to establish normal ocular examination parameters and vision testing protocols suitable for use in tree-kangaroos and the need for more comprehensive examination and testing of animals thought to have vision loss of unknown origin.