Ophthalmology Flashcards
What is cataracts?
The opacification of the crystalline lens.
What are the risk factors for cataracts?
Age > 65 years Smoking Long term UV exposure Diabetes Mellitus Eye trauma Long term ocular corticosteroid use FHx of congenital cataract or congenital toxins Uveitis
What is the aetiology for cataracts?
The normal ageing process Trauma Metabolic disorders (hereditary or acquired) Medications Congenital problems
What is the epidemiology for cataracts?
Cataracts accounts for 51% of reversible blindness worldwide
What are the presenting symptoms of cataracts?
Gradual decrease in vision over many years
-DM: relatively sudden reduction in vision
Blurred or cloudy vision
Washed out colour vision
Glare- particularly driving at night
Inadequate glasses prescription
What are the signs of cataracts on physical examination?
Reduced visual acuity
Defects in the red reflex (seen on ophthalmoscopy)
What are the appropriate investigations for cataracts?
Dilated fundus examination: fundus and optic nerve normal
Intra-ocular pressure: normal (or may be elevated if associated with glaucoma)
Glare vision test: significant cataract- reduced visual acuity under the conditions of glare stress*
Slit lamp examination of the anterior chamber: cataract visible
What is conjunctivitis?
Inflammation of the lining of the eyelids and eyeball
What is the aetiology of conjunctivitis?
Caused by: Bacteria Viruses Allergic or immunological reactions Mechanical irritation Medicines
Bacterial and viral conjunctivitis is highly contagious
What are the risk factors for conjunctivitis?
Exposure to infected person Infection in one eye Environmental irritants Allergen exposure Mechanical irritation Chronic contact lens useful Camps/ swimming pools
What are the presenting symptoms of conjunctivitis?
Watery discharge (viral) Ropy/ mucoid discharge, itching (allergic) Purulent discharge (bacterial) Eyelids stuck together in the morning (bacterial and viral)
What are the signs of conjunctivitis on physical examination?
Tender pre-auricular lymphadenopathy (more common in viral than bacterial infection)
Conjunctival follicles- round collections of lymphocytes
What are the appropriate investigations for conjunctivitis?
1st line:
Rapid adenovirus immunoassay- 2 visible lines equal positive
Others:
Cell culture/ Gram stain/ PCR- isolate viral or bacterial strains, amplify DNA
What is glaucoma?
Optic neuropathy with visual field loss and blindness usually associated with sustained raised intra-ocular pressure (ocular hypertension = IOP > 21 mmHg)
What is the aetiology for glaucoma?
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 (enlargement of the eyeball), other inherited ocular disorders
What is the uvea?
Vascular coat of the eyeball and lies between the sclera and retina. Composed of 3 parts: -Iris -Ciliary body -Choroid
Describe the anterior chamber
Between the cornea and lens and filled with clear aqueous fluid which is nutrient-rich
What is the role of the ciliary body?
Secrete aqueous fluid into the anterior chamber
What structure drains the aqueous fluid out of the eye?
Trabecular meshwork through the canal of Schlemm
What is normal intraocular pressure?
12-21 mmHg
What is Primary Open Angle Glaucoma?
The most common form of glaucoma- “trabecular meshwork dysfunction”
What is closed angle glaucoma?
Where increased ocular pressure pushes the iris/lens complex forwards, blocking the trabecular meshwork which drains the aqueous fluid- exacerbates the problem increasing pressure further
Can be acute or chronic
What is the epidemiology for glaucoma?
Prevalence 1 % in over 40 years, 10 % in over 80 years (POAG).
Third most common cause of blindness worldwide.
What are the presenting symptoms in acute closed angle glaucoma?
Painful red eye
Vomiting
Impaired vision
Haloes around lights.
What are the presenting symptoms in primary open angle glaucoma?
Usually asymptomatic- peripheral visual field loss may be noticed
What are the signs of acute closed angle glaucoma on physical examination (slit lamp)?
Red eye Hazy cornea Loss of red reflex Fixed and dilated pupil Eye tender and hard on palpation Cupped optic disc Visual field defect - arcuate scotoma = arc shaped visual defect near blind spot Moderately raised IOP.
What are the risk factors for acute closed angle glaucoma?
Small eye (hypermetropia) Narrow angle at trabecular meshwork
What are the signs of primary open angle glaucoma on physical examination (slit lamp)?
Usually no signs.
Optic disc may be cupped.
What are the appropriate investigations for glaucoma?
-Goldmann tonometry: measure ocular pressure
(normal 15 mmHg, POAG 22–40 mmHg, ACAG > 60 mmHg)
-ophthalmoscopy: measure cup to disc ratio
-*Gonioscopy: definitive test for angle closure glaucoma (trabecular meshwork is not visible in angle closure, because the peripheral iris is in contact with it)
What is uveitis?
Inflammation of one or all parts of the uvea
What is the anterior uvea composed of?
The iris and ciliary body
What can irritation of the anterior uvea cause?
Acute painful symptoms and photophobia
What risk can inflammation of the posterior uvea cause?
Painless visual loss
What is the aetiology of uveitis?
Divided into idiopathic, infectious, and non-infectious causes.
What are some of the infectious causes of uveitis?
Herpes simplex virus HIV Lyme disease Syphilis TB
What are some of the non-infectious causes of uveitis?
Inflammatory bowel disease Autoimmune disorders Sarcoidosis Multiple sclerosis Eye trauma
What are the risk factors for uveitis?
Inflammatory diseases of the joints, bowels or skin
History of ocular trauma and high risk occupation
What is the epidemiology of uveitis?
Can affect individuals of any age, sex, or geographical location without preference
What are the presenting symptoms of uveitis?
Pain (anterior uveitis) Decreased vision (blurred, visual field loss) Tearing Photophobia Eye redness without discharge (anterior)
What are the signs of uveitis seen on physical examination?
Flare: the hallmark of anterior uveitis, light scattering within the anterior chamber of the eye
Constricted/ non-reactive pupil (anterior)
Synchiae: seen during acute inflammation
(iris adherence to the cornea in anterior or lens in posterior)
Keratin precipitates: lymphocyte aggregation on the conceal endothelium
Optic disc swelling and retinal haemorrhages (posterior uveitis)
What are the appropriate investigations for uveitis?
1st line investigation: clinical diagnosis (history, symptoms and examination)
Others:
-FBC (elevated WCC in infection)
-ESR/ CRP (inflammation)
-HLA-B27 positive for patients with uveitis
-antibodies for infectious causes
