http://www.digitaljournal.com/article/305365

Duchess the 40-year old elephant treated for glaucoma at UK zoo

Posted Apr 4, 2011 by Kev Hedges
Duchess, the much-loved and popular African elephant at Devon's Paignton Zoo in south west England, is being treated for the eye disease glaucoma.
An African elephant eye
Nevit Dilmen
An African elephant eye
Glaucoma is a condition where the intraocular pressure (IOP) in the eye is inflated to a point where the optic nerve at the back of the eye is damaged. This can cause loss of peripheral vision eventually leading to blindness if left untreated. In humans, ophthalmologists prescribe eye drops to lower pressure, which in turn minimises further damage.
Veterinary officers at the zoo noticed Duchess' right eye had changed and are using eye drops in the same way as glaucoma specialists would on humans to lower IOP. The build up of fluid in the eye is caused by poor drainage in the trabecular mesh.
Duchess is the last surviving elephant in the zoo and has had cataracts in both eyes for years, reports BBC Devon. She should live to an age of around 65 years and has been successfully trained by keepers to lower her head when drops are being administered. As with human patients, drops into Duchess' eye will be applied daily for the rest of her life.
Last year the zoo lost the only other elephant, Gay, she was put down after developing gangrene on her foot.