Lecture 11 Flashcards
What causes primary glaucoma?
Unknown cause
What causes Secondary glaucoma?
Cause is unknown could be due to a tumour, contacts or diabetes
What is ocular hypertension?
Raised intraocular pressure in the eye
How is glaucoma diagnosed?
Dye in eye to observe the optic nerve
Visual field examination
Measure eye pressure
Determine if open or closed glaucoma (gonioscopy)
Measure the thickness of cornea (pachymetry)
Define primary open angle glaucoma
Caused by blockage in the trabecular mesh work which drains the anterior chamber of the eye to the episcleral veins through the canal of schlemm
Leads to pressure build up due to inadequate drainage of aqueous and vitreous humour
What is humour?
Fluid in the eye and it drains via the trabecular mesh work
Symptoms of primary angle glaucoma
Medical emergency
Severe pain
Headache
Change in vision
How is primary angle closure glaucoma managed?
Diuretics
Pilocarpine
Prostaglandins, beta blockers, sympathomimetics
Surgery
What are the issues with preservatives?
Cause side effects and can interact with contact lenses
What are miotics?
Involves construction of the pupil of the eye
Pulls iris away from trabecular mesh work - improves outflow opening up the angle further
What are miotics used for?
Acute glaucoma
What are the side effects of miotics?
Increased gastric acid secretion, affect HR and blood pressure as well as worsen asthma and seizures
Examples of a miotics
Pilocarpine - used to reduce pressure inside the eye
What do prostaglandin analogues do?
Increase uvoscleral outflow - outflow through the eye and out
Give examples of prostaglandin analogues
Bimatoprost, travoprost, latanoprost
What are carbonic anyhdrase inhibitors?
Decrease production of intraocular fluid
Increase perfusion of eye
Reduction in intraocular pressures
Example of a carbonic anhydrase inhibitor
Dorzolamide
What do symothomimetics do?
Very effective at reducing humour production and increase outflow
What are the side effects of sympathimimetics?
Blurred vision, discomfort, headache, nausea, hyperaemia
Example of sympathomimetics
Brimodine
What are beta blockers used for in the eye?
Reduces aqueous humour production
What are the issues with beta blockers?
Increased heart rate and asthmatic patients feeling more breathlessness
Define trabeculoplasty
Form of laser surgery that is used to lower intraocular pressure in glaucoma
Define tracbeculectomy
Type of glaucoma surgery performed on the eye that creates a pathway for fluid inside the eye to be drained
Role of anti metabolites
Prevent scarring by inhibiting the manipulation of cells which produce scar tissue
Example of antimetabolites
Mitomycin C or 5 flurouracil
Define visocanaloostomy
Remove part of the eye
Define deep sclerectomy
Widen the drainage tubes in the eye
Define cyclodiode laser
Destroys tissue in eye responsible for aqueous formation
How is closed angle glaucoma managed?
Medical treatment, laser treatment no surgical treatment
Aim to reduce intraocular pressure and slow progression of nerve damage
Reduce amount of AH produced or increase drainage through the trabecular mesh work
Define glaucoma
Optic nerve which connects the eye to the brain becomes damaged
Define acute angle closure glaucoma
Caused by the drainage in the eye becoming slightly blocked which raises the pressure in the eye
