Ophthalmology Flashcards
describe the location of damage to create
1. total right eye vision loss
2. bitemporal hemianopia
3. lest nasal hemianopia
4. right homonymous hemianopia
5. left homonymous hemianopia with macular sparing
pathophysiology of acute angle-closure glaucoma
- iris bulges forward and seals off the trabecular meshwork from the anterior chamber, preventing aqueous humour from draining
- continual buildup of pressure causing acute symptoms – emergency
risk factors for acute glaucoma
- Increasing age
- Family history
- Female (four times more likely than males)
- Chinese and East Asian ethnic origin
- Shallow anterior chamber
- Certain drugs – TCA, anticholinergics, adrenergics
presentation of acute glaucoma
- Generally unwell with a short history of severely painful red eye, blurred vision, halos around light, headache, n+v
- On examination:
o Red eye
o Hazy cornea
o Decreased visual acuity
o Mid-dilated pupil
o Fixed-size pupil
o Hard eyeball on gentle palpation
management of acute glaucoma
- Laser iridotomy usually required for definitive treatment (makes holes in iris for humour to flow from posterior chamber directly to anterior
- Pilocarpine eye drops – causes pupil constriction
- Acetazolamide (oral or intravenous) – carbonic anhydrase inhibitor
- Hyperosmotic agents (e.g., intravenous mannitol) increase the osmotic gradient between the blood and the eye
chronic/acute angle glaucoma
- Glaucoma = optic nerve damage caused by a rise in intraocular pressure
- Raised intraocular pressure is caused by blockage in aqueous humour trying to escape the eye
physiology of anterior/posterior chambers of eye
Anterior chamber of the eye is between the cornea and iris, posterior is between the lens and the iris – both are filled with aqueous humour (supplies nutrients, made by the ciliary body, drains through the trabecular meshwork to the canal of Schlemm then into general circulation)
pathophysiology of chronic/acute angle glaucoma
gradual increase in resistance through the trabecular network causing an increase in pressure
* Raised intraocular pressure causes cupping of the optic disc – optic cup is normally <50% of the size of the optic disk
risk factors of a chronic/acute-angle glaucoma
- Increasing age
- Family history
- Black ethnic origin
- Myopia (nearsightedness)
presentation of chronic/acute angle glaucoma
- gradual onset peripheral vision loss
- pain, headaches, blurred vision, halos around light
management of chronic/acute angle glaucoma
- 360° selective laser trabeculoplasty
- Prostaglandin analogue eye drops
- Trabeculectomy surgery if other treatments ineffective
cataracts
- Progressively opaque eye lens which reduces the light entry and visual acuity.
- Can be congenital and tested for with the red light reflex during NIPE
presentation of cataracts
- Slow reduction in visual acuity
- Progressive blurring of the vision
- Colours becoming more faded, brown or yellow
- Starbursts can appear around lights, particularly at night
- Loss of red light reflex
management of cataracts
surgery for new lens
blepharitis
- Inflammation of the eyelid margins
- Gritty, itchy, dry eyes
- Can be caused by dysfunction of the meibomian glands
- Can lead to styes and chalazions
- Warm compress and gentle cleaning
stye
- Hordeolum externum = infection of the glans of Zeis (sebaceous glands) or glands of Moll (sweat glands)
- Hordeolum internum = infection of the Meibomian glands – more painfull and deeper
- Hot compress and analgesia – topical abx if associated with conjunctivitis
chalazion
- Forms when a blocked Meibomian gland swells – often called a Meibomian cyst
- Swelling in eye lid – usually non-tender
- Warm compress, gentle massage towards eyelashes
entropion
- When the eyelid turns inwards – can cause pain, corneal damage and ulceration
- Tape eye lid down to prevent recurrence – need eye drops if eye stays open
- Definitive management is surgical
ectropion
- Eyelid turns outwards - can result in exposure keratopathy when eyeball exposed and not adequately lubricated