Pathology Flashcards
What is a cataract?
Opacification of the lens
What are potential causes of cataracts?
Age
Hypertension
Smoking
Trauma
Metabolic (e.g. diabetes)
Genetic
What produces pressure in the posterior eye?
The amount of vitreous fluid present.
What produces pressure in the anterior eye?
The amount of aqueous humor.
What are the 2 main forms of glaucoma?
Primary open-angled glaucoma
Acute close-angled glaucoma
What is the most common form of glaucoma?
Primary open-angle
It is the result of poor drainage through the trabecular meshwork.
What is affected in acute angle closure glaucoma?
Gap between the iris and lens has been narrowed, meaning fluid cannot reach the trabecular meshwork for drainage.
Which form of glaucoma has acute onset?
Close-angle glaucoma
May present with visual loss and severe headache.
How is acute closed-angle glaucoma treated?
Laser iridotomy
Is scleritis or episcleritis typically associated with painful eye movements?
Scleritis
What are the 3 forms of macular degeneration?
Age-related
Dry
Wet
What is used to differentiate between dry and wet macular degeneration?
The degree of vascular proliferation
What mediates the neovascularisation seen in wet macular degeneration?
VEGF
As vessels blocked, thus blood cannot get through.
Why does eye appear dark in CRVO?
Lots of backed-up blood due to venous occlusion.
Which distance vision is associated with large eyeballs?
Short-sightedness
Described as myopia.
Which distance vision is associated with small eyeballs?
Long-sightedness
Described as hypermetropia.
What can cause optic neuritis?
Demyelination
Most are unilateral
What can OCT be used to identify?
The presence of drusen.
What causes cotton wool spots to form?
Ischaemia of the retinal ganglion cells.
In which pathology are cherry red spots seen?
CRAO
Unilateral visual loss with macular sparing indicates which pathology?
Posterior cerebral stroke
What is the most common cause of diabetes in developed countries?
Diabetic retinopathy
What are the 3 eye conditions relate to diabetes?
Non-proliferative
Proliferative
Macular oedema
Microaneurysms, hard exudates, and intra-retinal haemorrhages, with no symptoms is descriptive of which level of diabetic retinopathy?
Mild-moderate non-proliferative
What are the 2 mechanisms involved in diabetic retinopathy?
Microvascular occlusion
Microvascular disease
What do cotton wool spots represent?
Ischaemia
A sign associated with more severe disease.
What occurs in proliferative retinopathy?
Neovascularisation
Vitreous haemorrhage
Traction
How may vitreous haemorrhage present?
If small, may describe floaters.
If large, may describe severe/complete visual loss.
How is severe NPDR treated?
Pan-retinal photocoagulation
Acts by decreasing total blood supply needed by the retina.
How is diabetic macular oedema treated?
Anti-VEGF therapy
How is vitreous haemorrhage/retinal detachment treated?
Vitrectomy
Which form of eye shape is associated with increased risk of retinal detachment?
Myopia
Associated with a thin retina, which is more likely to tear.
What is the difference between retinal detachment and rhegmatogenous detachment?
Retinal detachment involves separation of the sensory retina from the RPE (basement layer).
Rhegmatogenous detachment involves separation of RPE too. Following this, vitreous will get in behind RPE - resulting in retinal cell death.
Is a macular hole an ophthalmic emergency?
No - treat within 6 months.
Which cranial nerve is affected if eye appears internally rotated, pointed towards the nose?
CNVI palsy
Lateral rectus muscle is not supplied innervation as a result.
How does bilateral CNIV palsy present?
Torsion and a depressed chin.
What nerve supplies 6 ocular muscles?
CN III
What muscle are innervated by CNIII?
Medial rectus
Inferior rectus
Superior rectus
Inferior oblique
Levator palpebrae superioris
Sphincter pupillae
How does CNIII palsy present?
Closed eyelid, with eye deviated outwards and down.
Pupil will also be dilated.
What is internuclear ophthalmoplegia?
Dysfunction of the medial longitudinal fasciculus, resulting in impaired abduction of the affected eye, and nystagmus on abduction of the contralateral eye.
What is the only cause of monocular blindness?
CNII palsy
What may cause optic nerve palsy?
Ischaemic optic neuropathy
Optic neuritis
Tumor
What is optic neuritis?
Unilateral, progressive visual loss, with colour desaturation, and a central scotoma.
Recovery is gradual.
Is macula sparing seen in pathologies affecting the optic tracts/radiation?
No, only seen in disease of the occipital cortex.
It is not spared in optic tract/radiation pathology.
What can cause myopia?
Too large eye
Too much refractive power
Cornea too curved
Which eye shape/vision-type is suited to a converging lens?
Long-sightedness/hypermetropia
The focusses light earlier - making it meet on the retina.
What type of eye-sight is suited to a diverging lens?
Short-sightedness/myopia
Delays the convergence of light.
What is affected in an astigmatism?
The shape of the cornea
What eye complications are associated with myopia?
Retinal detachment
Open-angle glaucoma
What eye complications are associated with hypermetropia?
Closed angle glaucoma
What is presbyopia?
The reduction in lens contractility due to ageing.
Results in decreased ability to focus.
What are common causes of sudden visual loss?
Age-related macular degeneration
Bleed/Blocked vessel (e.g. vein/artery)
Closed-angle glaucoma
Detached retina
Think ‘ABCD’ of sudden visual loss.
What is the major blood supplying artery to the eye?
Ophthalmic artery
This is a branch of the internal carotid artery.
Is CRAO painful?
No - only symptom is sudden visual loss.
How will fundoscopy appear in CRAO?
Oedematous
Pale
‘Chery red’ spot
What is transient CRAO called?
Amaurosis fugax
What supplies blood to the optic disc?
Posterior ciliary arteries
How does temporal arteritis present?
Visual symptoms
Headache
Tender scalp
Enlarged temporal artery
What is the most common cause of blindness?
Age-related macular degeneration
What angle is affected in glaucoma?
That between the cornea and the iris.
What form of glaucoma is a medical emergency?
Closed angle glaucoma
Occurs when iris moves forward due to pressure within the eye, blocking off the pathway for fluid to the trabecular meshwork.
How does closed-angle glaucoma present?
Severe pain
Red eye
Sudden visual loss
Headache
Nausea
Vomiting
Dilated pupil
Why does the pupil dilate in closed angle glaucoma?
Ischaemia of the iris sphincter
How is wet ARMD treated?
Anti-VEGF therapy
What are common causes of gradual visual loss?
ARMD
Blur/Refractive error
Cataracts
Diabetes
Glaucoma
Think ‘ABCDG’ of gradual visual loss.
What may cause cataracts?
Age
Congenital
Diabetes
Trauma
Drug-induced (e.g. steroids)
What is the procedure for resolving a cataracts known as?
Phacoemulsification
What forms in dry ARMD?
Drusen
These are lipid deposits on the retina.
How is dry ARMD managed?
Supportive only, no pharmacological options are available.
What form of visual defect results in focus infront of the retina?
Myopia
What form of visual defect results in focus behind the retina?
Hypermetropia
Is open-angled glaucoma an issue to do with angle patency?
No, it is an issue with drainage at the trabecular meshwork.
What is the difference between drusen and exudates?
Drusen is a build-up of waste products.
Exudates are the leakage from vessels within the eye.
What should be suspected in those with bilateral optic disc swelling?
Raised ICP due to SOL.
What 3 components are crucial in determining ICP?
Brain
Blood
CSF
What may cause bilateral optic disc swelling in young obese women?
Idiopathic intracranial hypertension
A stellate cataract is pathognomonic of which condition?
Myotonic dystrophy
How does neurofibromatosis type 1 present in the eye?
Optic glioma
Lisch nodules
Remember this is an autosomal dominant condition, linked with cafe-au-lait spots.
What is an optic glioma?
A lesion of that grows around the optic nerve, resulting in proptosis.
What are lisch nodules?
Bilateral yellow/brown dome-shaped nodules of the iris which are pathognomonic of NF1.
What is the most common cause of both unilateral and bilateral proptosis?
Thyroid eye disease
What should always be considered as a potential cause of unilateral proptosis?
Neoplastic growth
How should thyroid eye disease be treated?
Treat dysfunction of thyroid gland
Smoking cessation
Selenium supplementation
Lubrication
What eye manifestations are linked with dermatomyositis?
Dry eyes
Scleritis
Be cautious of dermatomyositis as it can be a paraneoplastic syndrome.
What are common features of dermatomyositis?
Heliotrope rash (on eyelids)
Gottron’s papules
Proximal muscle weakness
Which malignancies must be excluded in those with dermatomyositis?
Ovarian
Breast
Lung
What eye manifestation is associated with Marfan’s syndrome?
A dislocated lens
How can dry eyes be diagnosed using fluoroscein?
Increased uptake of fluorescein indicates lots of small erosions on the cornea.
Treat with lubricants.
Which drugs cause ‘bullseye’ maculopathy?
Hydroxychloroquine
Chloroquine
Do steroids affect IOP?
Yes, cause a gradual rise in IOP bilaterally over a few months of therapy.
