Common Conditions of the Eye Flashcards
What is the bony orbit closely related to?
Air sinuses
Which parts of the bony orbit have very thin walls?
Everywhere except the orbital rims, lateral wall and superior walls
What can thin walls of the orbit lead to?
Herniation of contents into surrounding tissues
What is the conjunctiva?
Thin vascular membrane that covers the inner surface of the eyelids and loops back over the sclera
What is a blow out fracture?
The walls of the orbit can fracture (floor of medial wall usually) and contents can herniate out into e.g. maxillary sinus
The outer orbit remains fine
What is found when there is a blow out fracture, the orbital floor is fractured and there is herniation into the maxillary sinus?
Tear drop sign
What is the limbus?
The junction between the cornea and the sclera
What is found at the corneoscleral junction?
Lower eyelid
What appearance does a coloboma give?
Keyhole appearance
What causes coloboma?
An embryological anomaly due to choroid fissure not fusing
How can a retinal tear occur from blunt trauma?
Peripheral retina tears
Vitreous gel gets liquified
Liquid vitreous pushes through retinal tear and detaches it
What is the main function of vitreous gel?
Keep the retina in position
How does retinal attachment commonly occur?
Fluid getting into the “potential” space between the 9 inner layers of the retina and the outer 10 layers
What is conjunctivitis?
Self limiting bacterial or viral infection of the conjunctiva
Symptoms of conjunctivitis
Red eye Watery eyes Discharge Enlargement of blood vessels in the conjunctiva NO loss of vision
Treatment of conjunctivitis
Antibiotic eye drops if likely to be bacterial
If conjunctivitis causes loss of vision, what does this mean?
The infection has spread onto the cornea
What is damaged if there is an inability to lose the eyelid?
Left facial nerve paralysis
What is a phenomenon that also occurs when there is inability to close the eyelid?
Eyeball turned upwards
What can inability to close the eyelid lead to?
Drying of cornea which can lead to lesions
Two types of stye
External stye
Internal stye
Another name for external stye
Hordeolum externum
What causes an external stye?
Infection of a hair follicle (blockage of sebaceous glands)
Another name for an internal stye
Hordeolum Internum
What causes an internal stye?
Blockage and infection of the Meibonium gland (stuck inside the tarsal plate)
Treatment of a stye
Warm compress
Eyelid hygiene
May need surgical incision and curettage
Two types of corneal pathologies
Inflammatory e.g. corneal ulcers
Non-inflammatory e.g. dystrophies
What do corneal pathologies frequently lead to?
Opacification of the cornea
What is another name for a corneal transplant?
Keratoplasty
Causes of corneal ulcers
Inflammatory Infection - viral - bacterial - fungal Trauma Corneal degeneration Corneal dystrophy
Features of corneal dystrophies and degenerations
Bilateral Opacifying Non inflammatory Most genetically determined Sometimes due to accumulation of substances such as lipids in the cornea
When do corneal dystrophies and degenerations present?
First to fourth decade
Most common symptom of corneal degenerations and dystrophies
Decreased vision
Pathology of cataracts
Older (embryological, foetal) fibres never shed - and are compacted in the middle
No blood supply to the lens
Absorb harmful UV rays preventing them from damaging the retina but in the process, get damaged themselves
Damaged lens fibres become opaque leading to cataracts
Types of cataracts
Immature cortical cataracts
Mature cataracts
Nuclear sclerosis
Sutural and zonular cataract
Pathology of immature cortical cataracts
Seen as spoke like opacities
Outer cortical fibres that get opaque
Presentation of immature cortical cataracts
Usually fine during the day due to bright light but for example have stopped driving at night as too hazy
Treatment of cataracts
Surgery
How does the surgery work to treat cataracts?
Small incision Lens capsule opened Cataractous lens removed by emulsification (phacoemulsification) Plastic lens placed in capsular bag Lens implant after surgery
What is the lens called that is inserted after cataracts surgery?
Posterior chamber intra ocular lens (PCIOL)
What is glaucoma?
Raised intraocular pressure (IOP)
Two types of glaucoma
Open angle glaucoma
Angle closure glaucoma
Most common type of glaucoma
Primary Open Angle Glaucoma (POAG)
What are the consequences of raised IOP?
Pressure on nerve fibres on surface of the retina -> die out -> visual field defects
Pressure on the optic nerve head as the nerve fibres die out - optic disc on ophthalmoscopy appears unhealthy, pale and cupped
Results in an altered field of vision
Ultimately all nerve fibres are lost, which results in blindness
The triad of signs for the diagnosis of glaucoma
- Raised IOP
- Visual field defects
- Optic disc changes on ophthalmoscopy
Treatment of PAOG
Eye drops to decrease IOP - prostaglandin analogues - betablockers - carbonic anhydrase inhibitors Laser trabeculoplasty Trabeculectomy surgery
Presentation of open angle glaucoma
Bilateral
Can be asymptomatic for a long period of time
Picked up on routine eye exams
Presentation of angle closure glaucoma
Sudden onset Painful - ocular or headache Vision lost/blurred Headaches (often confused with migraine) Red eye Hard eye Cornea often opaque as raised IOP drives fluid into the cornea Pupil mid dilated and non reacting Haloes around lights IOP severely raised Systemic upset - N + V - abdominal pain
Features of the AC in angle closure glaucoma
AC shallow
Angle is closed
Pathology of angle closure glaucoma
- Functional block in a small eye - large lens
- Mid dilated pupil - periphery of iris crowds around angle and outflow is obstructed
- Iris sticks to pupillary border (synechia) which prevents reaching AC. Leads to iris ballooning anteriorly and obstructing angle
Treatment of an acute episode of angle closure glaucoma
Decrease IOP - IV infusion +/- oral therapu (carbonic anhydrase inhibitors) - Analgesics - antiemetics - constrictor eye drops (pilocarpine) - beta blocker e.g. timolol - steroid eye drops e.g. dexamethasone Iridotomy (laser)
Pathology of primary open angle glaucoma (POAG)
The drainage through the trabecular meshwork is blocked (in most cases)
Leads to a gradual, painless build up on IOP
Pathology of angle closure glaucoma
Some event on a predisposed eye leads to the peripheral iris blocking the angle, therefore the aqueous cant drain
So SUDDEN increase in IOP
In angle closure glaucoma, what does the patient usually present as?
An emergency
What is the vascular layer of the eye called?
Uvea
Function of the choroid
Supplies blood to the outer layers of the retina
Function of the ciliary body
Suspends the lens
Produces aqueous humour
Function of the iris
Controls diameter of the pupil and therefore controls the amount of light rays entering the eyeball
What is uveitis?
Inflammation of the uvea
Types of uveitis
Anterior uveitis
Intermediate uveitis
Posterior uveitis
What does anterior uveitis involve?
Iris with or without ciliary body inflamed
What does intermediate uveitis involve?
Ciliary body inflamed
What does posterior uveitis involve?
Choroid inflamed
Causes of uveitis
Isolated illness
Autoimmune causes e.g. presence of HLA-B27 predisposes to anterior uveitis
Infection e.g. chronic diseases such as TB
Assosiated with systemic diseases e.g. ankylosing spondylitis
Pathology of anterior uveitis
An inflamed uvea (iris) leaks plasma and white blood cells into the aqueous humor
When is anterior uveitis seen? What is seen?
During slit lamp examination
- a hazy anterior chamber and cells deposited at the back of the cornea
Cells in the AC may settle inferiorly - hypopyn
Presentation of anterior uveitis
Red eye
Painful
Visual loss
Pathology of intermediate uveitis
Ciliary body is inflamed and leaks cells and proteins leading to hazy vitreous
Presentation of intermediate uveitis
Patient complains of “floaters” or hazy vision
Pathology of posterior uveitis
Choroid inflamed
Since the choroid sits under the retina the inflammation frequently spreads to the retina and can cause blurred vision
Is there lymphatics in the eyeballs?
No
Is there lymphatics in the eyelids?
Yes
What is the treatment for proliferative vessels?
Laser treatment
Features of the eye in diabetic retinopathy
Usually no symptoms Usually fine vision in both eyes Hard exudates - yellow and waxy looking Blot haemorrhages Microaneurysms Cotton wool spots
Types of diabetic retinopathy
Proliferative
Non-proliferative
Main feature of proliferative diabetic retinopathy
New vessels can grow
Main feature of non proliferative diabetic retinopathy
No new vessels grow
Which type of diabetic retinopathy is more aggressive?
Proliferative
What are cotton wool spots a sign of?
Ischaemia
What do new vessels typically look like?
Small
Grow in places they shouldn’t
Where do new vessels often grow?
Optic disc
Where can new vessels grow?
Optic disc
Vitreous
What is the result of new vessels growing into the vitreous?
They can bleed and scar - this can pull the retina
Types of maculopathy
Exudative
Ischaemic
Treatment of exudative maculopathy
anti VegF
Steriods
Features of ischaemic maculopathy
Look normal
Vision down
Treatment for ischaemic maculopathy
No treatment
Predisposing factors for acute closed angle glaucoma
Hypermetropia
Pupillary dilatation
Lens growing with increased age
