The Canine Glaucomas Flashcards
in glaucoma, what is the primary target of tissue generation?
retinal ganglion cells
what type of glaucoma is most common in veterinary species?
primary angle closure glaucoma (PACG)
what is the reported prevalence of glaucoma in domestic dog populations?
1-2%
what are the 3 main features of primary glaucoma
elevation in IOP without concurrent disease
hereditary in many breeds
likelihood of bilateral development
what abnormalities can result in primary glaucoma?
abnormal biomechanical metabolism of the trabecular meshwork cells (POAG)
physical effects of pupillary blockage and changes in ICA and ciliary cleft (PACG)
what parts of the ICA can be visualised by gonioscopy?
pectinate ligaments, part of uveal trabeculae, anterior opening of the ciliary cleft
at what pressure does corneal endothelial dysfunction develop?
40mmHg
what area of the retina is more sensitive to high IOP?
peripheral
what are the 3 types of tonometry?
indentation, applanation and rebound
how do applanation tonometers work?
They have a force plate in their tips that measures the amount of force necessary to indent or flatten a defined surface area of cornea. That force is then correlated to the IOP, an internal force that generates turgidity
How do rebound tonometers work?
a magnetic field is induced that propels a small magnetized probe against the cornea.
The probe “rebounds” from the cornea at different velocities (dependent upon the level of IOP), causing voltage changes within the tonometer’s collar, which are converted into electrical signals calibrated to different levels of IOP
what time of day does the IOP tend to be highest in the dog?
early morning
what time of day does IOP tend to be lowest in the dog?
early evening
what breeds of dog does the ECVO advise have gonioscopy prior to breeding?
ACS, all types of Bassets, Bouvier des Flandres, Chow Chow, Border Collie,
Dandy Dinmont Terrier, Rough‐Haired Dutch Shepherd, English Springer Spaniel, Entlebucher Mountain Dog, Flat‐Coated Retriever, Siberian Husky, Leonberger, Magyar
Vizsla, Samoyed, and Tatra
what are the 4 classifications of PLD given by the ECVO?
free
fibrae latae (abnormally broad and thickened pectinate ligament fibers)
laminae (solid plates or sheets of pectinate ligament tissue)
occlusio (persistence of an embryonic sheet of ICA tissue and the absence of intraligamentary spaces, except for flow holes).
