Opthalmology Flashcards
Define cataracts.
The opacification of the crystalline lens that results from the normal ageing process, trauma, metabolic disorders (hereditary or acquired), medications or congenital problems.
Explain the aetiology / risk factors of cataracts.
Most cataracts develop when aging or injury changes the tissue that makes up your eye’s lens. Some inherited genetic disorders that cause other health problems can increase your risk of cataracts. Cataracts can also be caused by other eye conditions, past eye surgery or medical conditions such as diabetes.
Risk Factors:
- Age >65 years
- Smoking
- Long-term UV exposure
- DM
- Eye trauma
- Long-term corticosteroid use
- Family history of congenital cataract or congenital influences - e.g. toxins
- Uveitis
Summarise the epidemiology of cataracts.
The most common cause of curable blindness in the world.
Recognise the presenting symptoms of cataracts.
- Subjective decrease in vision
- Blurred or cloudy vision
- Glare
- Washed-out colour vision
- Reduced visual acuity
- Defects in the red reflex
- Inadequate glasses prescription
- Disruption in activities of daily living
Recognise the signs of cataracts on physical examination.
- Subjective decrease in vision
- Blurred or cloudy vision
- Glare
- Washed-out colour vision
- Reduced visual acuity
- Defects in the red reflex
- Inadequate glasses prescription
- Disruption in activities of daily living
Identify appropriate investigations for cataracts and interpret the results.
- Dilated fundus examination
- Measurement of intra-ocular pressure
- Glare vision test
- Slit lamp examination of the anterior chamber
- Assessment of best visual potential
Define conjunctivitis.
The inflammation of the lining of the eyelids and eyeball caused by bacteria, viruses, allergic or immunological reactins, mechanical irritation, or medicines.
Explain the aetiology / risk factors of conjunctivitis.
Risk Factors:
- Exposure to infected person
- Infection in one eye
- Environmental irritants
- Allergen exposure
- Camps, swimming pools, military bases
- Asian or Mediterranean young male
- Atopy
- Contact lens use
- Ocular prosthesis
- Mechanical irritation
Summarise the epidemiology of conjunctivitis.
The incidence of bacterial conjunctivitis was estimated to be 135 in 10 000 in one study.
Recognise the signs of conjunctivitis on physical examination.
- Watery discharge
- Ropy, mucoid discharge
- Purulent discharge
- Itching predominant symptom
- Eyelids stuck together in morning
- Tender, pre-auricular lymphadenopathy
- Conjunctival follicles
- Superficial punctate keratopathy
- Unilateral disease
- Corneal subepithelial infiltrates
- Corneal pannus
- Vesicular skin rash
Identify appropriate investigations for conjunctivitis and interpret the results.
- Rapid adenovirus immunoassay
- Cell culture
- Gram stain
Identify appropriate investigations for conjunctivitis and interpret the results.
- Rapid adenovirus immunoassay
- Cell culture
- Gram stain
- Polymerase chain reaction
- Ocular pH
Define glaucoma.
Optic neuropathy with typical field defect usually associated with ocular hypertension (intra-ocular pressure, IOP > 21mmHg).
Explain the aetiology / risk factors of glaucoma.
Ocular hypertension compresses and stretches the retinal nerve fibres leaving the optic disc causing scotomas and visual field loss.
Ocular hypertension is caused by reduced outflow of aqueous humour caused by:
- Obstruction to outflow by approximation of iris to cornea closing iridocorneal angle and trabecular meshwork / canal of Schlemm causing a rapid and severe rise in IOP (ACAG)
- Resistance to outflow through trabecular meshwork (POAG)
- Blockage of trabecular meshwork by blood or inflammatory cells
Primary Causes:
- Acute closed-angle glaucoma (ACAG)
- Primary opened-angle glaucoma (POAG)
- Chronic closed-angle glaucoma
Secondary Causes:
- Trauma
- Uveitis
- Steroids
- Rubeosis iridis - diabetes, central retinal vein occlusion
Congenital:
- Buphthalmos
- Other inherited ocular disorders
Summarise the epidemiology of glaucoma.
Prevalence 1% in over 40 years, 10% in over 80 years (POAG).
3rd most common cause of blindness worldwide.
