Ophthalmology Flashcards
Simply conjunctivitis does not usually require a specialist referral unless one or more of what three features occur?
- Symptoms do not abate for more than two weeks
- The eye becomes painful
- Vision decreases
How is bacterial conjunctivitis usually treated?
Topical broad-spectrum antibiotics e.g. chloramphenicol
What are some features of gonnococcal conjunctivitis?
Rapid onset
Copious amounts of discharge
Chemosis (conjunctival oedema)
Lid oedema
Describe the clinical course of viral conjunctivitis?
Self-limiting
What precautions should be taken to prevent the spread of conjunctivitis? Why is so much care required?
Conjunctivitis is very contagious
Strict hygiene and separate towel use from other family members while the eye is still red.
What is the function of the sclera?
Thick, protective membrane forming the outer coat of the eyeball (white of the eye)
What is the function of the cornea?
Transparent dome-shaped anterior portion of the outer covering of the eye. Provides the eye with its refractive power
What is the function of the conjunctiva?
Richly vascular mucous membrane covering the anterior surface of the sclera and reflected onto the undersurface of the eyelids
What is the function of the anterior chamber of the eye?
Contains aqueous humour (produced by the ciliary body and drained via the canal of Schlemm) providing nutrients and oxygen to the cornea
What is the function of the iris?
Coloured part of the eye, muscles regulate the size of the pupil and thus the amount of light entering the eye.
What is the function of the lens?
Transparent biconvex disc which changes shape in order to alter the refractive power of the eye
What is the function of the retina?
Contains two types of photoreceptors:
- Cones (provide colour vision and are confined mainly to the central macula)
- Rods (providing night/low-light vision)
What is the area in the centre of the macula called? What is its function?
Fovea
Highest density of cone photoreceptors - meaning the central vision is the most acute
What types of visual field anomaly is present during a migraine?
Temporary blurring or “zig-zag” lines
What is amaurosis fugax?
Severe temporary visual loss due to a transient lack of blood supply to the retina or visual cortex - commonly occuring due to TIA
What is the occurence of amaurosis fugax considered a “warning sign” of?
Impending blindness of stroke
What feautes of a history would indicate conjunctival infection?
Often bilateral diffuse redness Itchy Gritty Purulent discharge No pain Normal acuity
What feautes of a history would indicate subconjunctival haemorrhage?
May occur after rubbing eye, severe coughing or hypertension
Unilateral bright red area
Normal acuity
What is subconjunctival haemorrhage?
Bleeding between the sclera and conjunctiva
What is episcleritis?
Inflammation of the episclera causing mild irritation and redness of the eye
No change in acuity
What feautes of a history would indicate keratitis?
History - paini, foreign body sensation, blurred vision, photophobia
Reduced acuity
Maximal redness around the cornea
What complication of keratitis could occur that may be difficult to identify? How would you go about observing it?
Corneal ulceration
More easily visible with fluouriscien drops and blue light
What is acute glaucoma?
Sudden and severe rise in intraocular pressure due to reduced aqueous fluid drainage
What features of a history would indicate acute (closed-angle) glaucoma?
- Sudden onset of severe pain with diffuse redness
- Blurred vision
- “Halos around lights”
- Nausea and vomiting
- Fixed and dilated pupils
What is endopthalmitis?
Infection of the eyeball following eye surgery, injury of spread via the blood
List some conditions characterised by a gradual loss of vision
(6)
Optic Atrophy Chronic glaucoma Cataracts Diabetic retinopathy Macular degeneration Chronic retinal detachment
What two infections seen in developing countries can cause visual loss?
Chlamydia trachomatis
Onchocerciasis (river blindness)
List some conditions can cause sudden/rapid visual loss
6
Acute retinal detachment Retinal vein occlusion Retinal artery occlusion Acute optic neuropathy Vitreous haemorrhage "Wet" Age-related macular degeneration
What examination findings would support a diagnosis of acute retinal detachment?
Pupil in affected eye dilates in response to light (relative afferent pupillary defect, RAPD)
Abnormal red-reflex: Retina looks grey and wrinkled
What examination findings would support a diagnosis of retinal vein occlusion?
Retinal haemorrhages
Tortuous dilated veins
Macular oedema
Cotton wool spots (infarct)
What examination findings would support a diagnosis of retinal artery detachment?
Pale retina with central macular “cherry red spot”
What progressive neurological condition is most strongly associated with acute optic neuropathy?
Multiple sclerosis
What features of the history/examination indicate age-related macular degeneration?
History - sudden distortion or blurring of vision with central scotoma (central loss of vision)
Examination - macular oedema and/or subretinal haemorrhages
What patients groups are most at risk of developing chronic (open-angle) glaucoma?
Those with a positive family history Elderly Diabetes mellitus Myopic patients Black race
What medical treatment options are available to patients with glaucoma?
Beta-blocker eye drops (decrease aqueous humour production)
Alpha-adrenergic agonists (decrease aqueous humour production)
Prostaglandin analogues (improve humour drainage)
What surgical options are available to treat glaucoma?
Laser surgery - induces changes in trabecular networks allowing better drainage of aqueous humour
Trabeculectomy - creates an opening in the anterior chamber
What is accommodation?
Changing of the lens shape to focus near objects using the ciliary muscles
What is acuity?
A measure of how well the eye can see a small object
What is amblyopia?
Decreased acuity uncorrectable by lenses with no anatomical defect
What is an Amsler grid?
Test chart of intersecting lines useful in the diagnosis of Age-Related Macular Degeneration (ARMD) - line distortion in the middle (central scotoma) is the key feature
What is anisocoria?
Unequal pupil size
What is anisometropia?
The state of having different refractive defects in each eye
What is aphakia?
The state of having no lens (i.e. after removal in cataract surgery)
What is blepharitis?
Inflammed eyelids
What are the canthi?
Singular canthus. The medial or lateral angles made by open eyelids
What is chemosis?
Oedema of the conjunctiva
What is the choroid?
The vascular coat between the retina and the sclera
What is the ciliary body?
Portion fo the uvea between the iris and the choroid. Containing the ciliary processes and muscle
What is the conjunctiva?
mucous membrane on the anterior sclera and posterior lid aspect
What is cycloplegia?
Ciliary muscle paralysis preventing accomodation
What is dacryocystitis?
Inflammation of the lacrimal sac
What is a dioptre?
Unit for measuring refractive power of lenses
What is ectropion?
The lids evert (especailly the lower lid)
What is entropion?
The lids invert (so that lashes irritate the eye)
What is epiphora?
Passive overflow of tears onto the cheek
What is the fornix?
Where the bulbar (scleral) and palpebral (lid) conjunctivae meet
What is the fovea?
Cone-rich part of the central macula
What is the fundus of the eye?
That part of the retina normally visible through the fundoscope
What is keratoconus?
Cone shaped cornea
What is keratomalacia?
Corena is softened
What is the limbus?
The annular border between the sclera and the cornea
What is the macula?
Retinal area approx. 5mm across lateral to the optic disc
What is a miotic agent?
An agent that serves to pupil constriction (e.g. pilocarpine)
What is a mydriatic agent?
An agent causing pupillary dilation (e.g. tropicamide)
What is the near point?
Where the eye is looking when maximally accomodated
What is the optic disc?
The part of the optic nerve seen in the fundus
What is the optic cup?
The cup-like depression in the centre of the optic disc
What is papillitis?
Inflammation fo the head of the optic nerves
What is presbyopia?
Age-related reduced near acuity from failing accomodation
What is ptosis?
Drooping lids
What is refraction?
Light ray deviation on passing through media of different density
What is retinal detachment?
The sensory retina separates from the pigmented epithelial layer of the retina
What is the sclera?
The whites of the eyes starting from the corneal perimeter
What is scotoma?
A defect causing a part of the visual field to be lost
What is strabismus?
Commonly called a squint. Eyes deviate and dont look in the same direction
What is a tonometer?
A device for measuring intraocular pressure
What is the uvea?
Collective term for iris, ciliary body and choroid
What is a vitrectomy?
Surgical prcedure to remove the vitreous of the globe
What is the vitreous?
Jelly-like substance filling the globe behind the lens
What is a stye?
A colloquial terms for inflammatory lid swellings
What are the different types of styes?
Hordeolum externum (most common) - infection of a lash follicle
Hordeolum internum (less common) - abscess of Meibomiam glands - as they heal they form calazions (granuloma) before resolving
What is the common presentation fo retinoblastoma?
Absence of red reflex
Strabismus
Leukoria (white pupil)
Retinoblastoma shows a hereditary component. What inheritance pattern is shown? What gene is implicated?
Autosomal dominant
RB gene at 13q14
What treatment options are available for retinoblastoma?
Chemotherapy Enucleation (removal of the eye) External beam radiotherapy Ophthalmic plaque bradytherapy Cryotherapy and transpupillary thermotherapy
What is orbital cellulitis?
A severe and life/sight threatening emergency caused by infection of the soft tissues posterior to the orbital septum
What is the typical presentation of orbital cellulitis?
Inflammation of the orbit, fever, lide swelling and decreased eye motility
Potential double vision, visual impairment and proptosis
What are the most common complications of orbital cellulitis?
Subperiosteal and orbital abscess
How is orbtial cellulitis distinguished from pre-septal/periorbital cellulitis?
The absence of painful eye movements, diplopia and visual impairment distinguish preorbital cellulitis
What are the features of a third cranial nerve palsy?
Ptosis, proptosis with the pupil looking down and out
What are the features of a fourth cranial nerve palsy?
The eye looks upwards and in adduction and is unable to look down and in due to superior oblique paralysis
What are the features of a sixth cranial nerve palsy?
Diplopia in the horizontal plane
What nerve is responsible for the afferent pathway in the pupillary response?
Optic nerve
What nerve is responsible for the efferent (constriction) pathway in the pupillary response?
Oculomotor nerve
What is scleritis?
Generalised inflammation fo the sclera with oedema of the conjunctiva
Types include anterior (90%), posteiror and necrotising (most severe)
How does scelritis present?
Deep, boring ocular pain and pain on eye movements (due to recti inserting on the sclera)
Bright red injection of the white of the eye.
What is episcleritis? How does this differ from scleritis?
Inflammation below the conjunctiva (episcleritis)
Hyperaemic vessles are mobile when prodded with a cotton bud and blanching on application of phenylephrine
What is the treatment for scleritis/episcleritis?
Topical/systmeic NSAIDs
More commonly prednisolone in scleritis
What are the most common causes of anterior uveitis?
Underlying autoimmune conditons
How does anterior uveitis calssically present?
Pain, blurred vision and photophobia
What signs may be seen in the case of anterior uveitis?
Corneal precipitates (seen on slit lamp)
Posterior synechiea (iris adhesion to the lens causing irregular pupillary border)
What is the most common vascular occlusion in the eye?
Central retinal artery occlusion
What are the symptoms of retinal artery occlusion?
Dramatic visual loss within seconds of occlusion
What is the characteristic examination finding of retinal artery occlusion?
Retinal pallor with ‘cherry red’ spot macula
What are the characteristic examination findings of retinal vein occlusion?
Optic nerve sweling, tortousous veins and cotton wool spots around vessles (areas of infarct)
How is retinal vein occlusion related sight loss managed?
Intravitreal anti-VEGF followed by dexamethasome implants
Photocoagulation (if there is retinal neovascularisation)
Bleeding into the vitreous is called what?
Vitreous haemorrhage
What are the causes of vitreous haemorrhage?
Retinal neovasculariisation
Retinal tears/detachement
Trauma
Outline the symptoms of small and large vitreal haemorrhages
Small extravasations - vitreous floaters
Large extravasations - potential blindness
What is the chief cause of registerable blindness in the UK?
Age-related macular degeneration
What is the pathogenesis of age-related macular degeneration?
There is pigment, drusen and sometimes bleeding into the macula
What are the typical symptoms of age-related macular degeneration?
Decreased acuity (difficulty reading, recognising faces, poor night vision, visual fluctuation)
Metamorphopsia - distortion of central vision
What are the different types of age-related macular degeneration?
Wet (exudative) - pathological choroidal neovascularisation under the retina
Dry (non-exudative) - progressive visual loss
What are cataracts?
Lens opacification causing gradual and painless visual loss
What is the management plan of cataracts in a neonate?
Intervention needs to be done within the latent period of visual development (first six weeks of life) to avoid significant deprivation amblyopia
What is retinal detachment?
Separation of the sensory retina from the retinal pigment epithelial layer (RPE)
What are the four F’s of retinal detachament symptoms?
Floaters
Field loss
Fall in acuity
Flashes
How are retinal detachments treated?
Urgent referral for surgery either by vitriectomy and gas tamponade followed laser coagulation to secure the retina
