Ophthalmology & Skin - Level 1/2 Flashcards
Definition of glaucoma?
- Glaucoma is group of eye diseases that cause progressive optic neuropathy, associated with raised IOP and characterised by visual field defects and changes to optic nerve (pathological cupping, pallor of disc)
- Raised IOP = >21mmHg
Anatomy of eye - anterior chamber?
o Anterior chamber – fluid-filled space between iris and cornea
Angle is between iris and cornea where they join sclera towards outside of the eye
Trabecular network situated in apex of anterior chamber angle and is main aqueous outflow route
Anatomy of eye - aqueous humour?
o Aqueous Humour – fluid produced from plasma by ciliary epithelium of ciliary body
Secreted into posterior chamber which is space between iris and lens, flows through pupil into anterior chamber and out of trabecular meshwork
Secretion increased by stimulation of beta-2 receptors and decreased by stimulation of alpha-2 receptors on ciliary body
Normal IOP of eye?
Pressure between 11-21mmHg is normal
Classifications of glaucoma?
o Age of onset – congenital, infantile, juvenile, adult
o Cause – primary, secondary
o Rate of onset – acute, subacute, chronic
o Anterior chamber open or closed
Definition and types of open angle glaucoma?
o Primary open angle glaucoma
Most common, >40 years, insidious onset, both eyes usually, raised IOP
o Normal tension glaucoma
POAG in normal IOP
o Secondary OA glaucoma
Definition and types of angle closure glaucoma?
o Primary angle closure glaucoma
Onset may be acute, subacute or chronic
Acute is medical emergency
o Secondary angle closure glaucoma
How common is ocular hypertension, POAG, PACG?
- Ocular hypertension – 3-5% of over 40 year olds
- POAG – 2% of over 40s – increases with age
- PACG – women 3x more, increases with age
Risk factors of open angle glaucoma?
Raised IOP Older age FHx Black people Corticosteroid treatment Myopia T2DM Hypertension
Risk factors of angle-closure glaucoma?
Older age
Women 2-3x
Asian people
Short, hyperopic eyes
Aetiology of primary open angle glaucoma?
Visual loss due to damage to retinal ganglion cells due to raised IOP causing mechanical pressure damage to axons of cells
Aetiology of secondary open angle glaucoma?
Pseudoexfoliative – organelles deposited on trabecular meshwork
Pigmentary – pigment from iris deposited in trabecular meshwork
Neovascular – diabetic retinopathy, central retinal vein occlusion
Uveitic – uveitis
Steroid-induced
Angle-recession – trauma
Aetiology of primary angle-closure glaucoma?
Peripheral iris comes into contact with trabecular meshwork that restricts drainage of aqueous humour from eye
Symptoms of acute angle closure glaucoma?
o Eye pain – severe
Spreads around orbit with generalied headache
o Headache, nausea and vomiting
o Red eye
o Impaired visual acuity, blurred vision and lights seen surrounded by halos (hazy oedematous cornea)
o Semi-dilated and fixed pupil (fixed in vertically oval shape)
o Tender, hard eye
Symptoms of ocular hypertension and POAG?
o Usually by optometrists in routine eye exams
o Increased IOP, visual field defects and cupped optic disc
When should people get examined for glaucoma?
- Advise people with the follow risk factors to get eyes examined:
o Older age
o FHx of glaucoma
o Black African
Management of acute angle closure glaucoma - primary care?
Admit immediately for specialist ophthalmology assessment and treatment
If immediate admission not possible – start emergency treatment
• Person lie flat with face up and head not supported by pillows
• Drugs – pilocarpine eye drops (1 drop of 2% in blue eyes, 4% in brown eyes), acetazolamide 500mg oral, analgesia and anti-emetic PRN
Management of acute angle closure glaucoma - secondary care initial treatment?
• Topical and IV drugs to reduce IOP
o Pilocarpine
o Acetazolamide
• Analgesia
Management of acute angle closure glaucoma - secondary care definitive treatment?
- Laser iridotomy (creates holes in iris to allow aqueous humour to flow into anterior chamber)
- Iridoplasty or cataract removal
Management of POAG or ocular hypertension - drug treatment?
o Under direction of ophthalmologist
o Drug treatment
Topical prostaglandin analogue or prostamide
• Latanoprost, travoprost
Topical beta-blocker
o Lifetime monitoring
Management of POAG or ocular hypertension - other treatments?
Add other drug or carbonic anhydrase inhibitor
Laser procedures
• Selective laser trabeculoplasty
• Argon laser trabeculoplasty
• Micro-pulse laser trabeculoplasty
Surgical procedures
• Trabeculectomy
• Insertion of drainage shunt
Prognosis of POAG?
o Progresses slowly without treatment over years, most people asymptomatic until severe disease
o Visual loss is peripheral at first
Prognosis of PACG?
o Half of glaucoma related blindness
o Needs prompt treatment
Definition of cataracts?
- Opacity forming within lens of the eye which reduces transparency