Glaucoma Flashcards
Does having a high IOP equate to a diagnosis of glaucoma?
No - can be made with normal IOP
But high IOP is a risk factor for development of glaucoma
What is the most common type of glaucoma?
Open angle glaucoma (chronic simple glaucoma)
What causes open angle glaucoma?
Trabecular meshwork deterioration (slow clogging)
What happens in open angle glaucoma?
Typically: rise in intra ocular pressure and damage to optic nerve (outer rim atrophy -> peripheral vision loss)
Can progress to central visual loss
Open angle glaucoma affects what percentage of people over 40?
0.5%
Does open angle glaucoma affect more men or women?
Equal
Other than age, what risk factors are there for open angle glaucoma?
FH African- Caribbean Myopia HTN DM Thyroid eye disease Corticosteroids Screening for these high risk groups
Why should there be screening for open angle glaucoma?
Patients are asymptomatic until visual field changes advanced, at which point little can be done
What fundoscopy signs are seen in open angle glaucoma?
Optic disc cupping
Optic disc pallor indicating atrophy
Disc haemorrhages
What is the normal cup to disc ratio and what is seen in open angle glaucoma?
Normal: 0.4-0.7
> 0.7 in open angle glaucoma
How is open angle glaucoma diagnosed?
Tonometry to measure IOP
Central corneal thickness measurement
Gonioscopy to assess peripheral anterior chamber configuration and depth
Visual field measurement
Slit lamp with pupil dilation to assess optic nerve and fundus
How is open angle glaucoma treated?
Drugs:
Prostaglandin analogues (latanoprost) - increase uveoscleral outflow
Beta blockers (timolol) - reduce aqueous production
Alpha agonists (brimonidine) reduce aqueous and increase uveoscleral outflow
Carbonic anhydrase inhibitors (acetazolamide) reduce production of aqueous
Miotics (pilocarpine) reduce resistance to aqueous outflow
Laser therapy (trabeculoplasty)
Surgery
What is acute closed angle glaucoma?
A form of glaucoma where the angle of the anterior chamber narrows acutely causing a sudden rise in intraocular pressure to more than 30mmHg
What features are associated with acute closed angle glaucoma?
Severe pain - ocular or headache
Decreased visual acuity
Hard eye
Red eye
Haloes around light and blurring of vision due to corneal oedema
Semi dilated non reacting pupil, often oval shaped
Systemic upset - nausea, vomiting, abdo pain
What can make acute closed angle glaucoma worse?
Mydriasis e.g watching TV in dark room, eye patches
Primary acute closed angle glaucoma occurs in patients with an …
Anatomical predisposition
Secondary acute closed angle glaucoma occurs from pathological processes such as..
Traumatic haemorrhage pushing posterior chamber forwards
What is the peak incidence for acute closed angle glaucoma?
40-60
Is the rise in IOP in ACAG rapid or gradual?
Rapid
Is acute closed angle glaucoma an emergency?
Yes requires rapid recognition and management as irreverent sight loss can occur in a few hours
How should acute closed angle glaucoma be managed?
Send for gonioscopy
Start triad of: beta blockers to suppress aqueous production, pilocarpine (miosis opens a closed drainage angle) and IV acetazolamide to reduce aqueous formation
Analgesia
Antiemetics
Admit to monitor IOP
Peripheral iridectomy (laser or surgery) once IOP controlled - piece of iris removed in both eyes to allow aqueous to flow
If increased IOP is detected, what type of follow up is required?
Life long
Describe tonometry
Eye numbed with eye drop anaesthesia
Tonometer pressed against eye
Force with which the eye pushes back use to estimate pressure in eye
Define glaucoma
Optic neuropathy with death of many retinal ganglion cells and their optic nerve axons. IOP may be raised, but this is not part of the definition
What side effects can prostaglandin analogues have?
Brown pigmentation on iris
Increase eyelash length
Periocular skin pigmentation
Red eye
Beta blockers should be avoided in those with..
Asthma
Heart block
