BILATERAL PHACOFRAGMENTATION IN A KOMODO DRAGON (Varanus komodoensis)

摘要

Although not an uncommon clinical entity in reptiles, there is a paucity of published information on the etiology, pathogenesis, clinical manifestations and treatment of cataracts in reptiles. Lenticular degeneration with opacification, or cataract formation, probably occurs in reptiles for similar reasons as in mammals and birds. Cataracts are usually classified by age of onset (congenital, juvenile, senile), anatomic location, cause, degree of opacification (incipient, immature, mature, hypermature), and shape. Cataracts may be inherited (particularly in dogs) but other etiologies include diabetes mellitus, malnutrition, radiation, inflammation, and trauma. Cataracts may be unilateral or bilateral depending on the etiology, and the rate of cataract formation may be different in each eye. Most cataracts result in impaired vision to a greater or lesser degree. Vision may be regained in young animals when cataracts undergo sufficient spontaneous resorption, and congenital nuclear cataracts in younganimals may reduce in size with the growth of the lens, restoring vision as the animal grows. Lenticular sclerosis characterized by variable degrees of central fiber compaction in the substance of the crystalline lens has been reported in reptiles. Thiscauses the lens to appear slightly silver-grey but does not seem to impair vision. The etiology of cataracts in reptiles is often obscure. In those few cases where an etiology could be surmised, it was usually secondary to uveitis or trauma. Nutritionaland environmental factors have also been implicated in some cases. They have been reported and observed in a wide range of reptile species. Lens opacity may vary from small focal nuclear or cortical opacities, to dense cataracts. Cataracts have been reported in reptiles at various ages with some being evident at birth. Juvenile cataracts have been reported in young varanid lizards.2 The etiology is unclear, although a genetic predisposition has been suggested. Senile cataracts in aged captive reptiles have been reported. Post hibernation blindness in European tortoises due to cataract development, vitreal opacification, and central nervous system, deficits is a well recognized syndrome. At present the only definitive therapy for cataracts is surgical removal of the lens. Early cataract removal using current surgical techniques (phacofragmentation) has high success rates in other species. There are no reports in the readily available literature of cataract extraction in a reptile. This paper reports successful bilateral phacofragmentation with restoration of vision in an adult male Komodo dragon (Vor anus komodoensis).