Common conditions of the eye Flashcards
List of conditions contained within
- Cavernous Sinus Infection
- Coloboma
- Retinal Detachment
- Ptosis
- Inability to close the eye
- Stye
- Corneal ulcer & Dystrophy
- Cataract
- Glaucoma
How could cavernous sinus thrombosis occur from an eye condition? [2]
What serious sequelae could arise [1]
Could start with orbital cellulitis [1]
Infection spreads through the valveless emissary veins [1] to the cavernous sinus [1] and lead to thrombosis
Blindness is a risk from optic nerve pressure or thrombosis of its vessels
Can cause Horner’s syndrome
How would a cavernous sinus thrombosis present? [6]
Appearance on ophthalmoscope [1]
The eye would be swollen [1], red [1] and painful [1] from build up of venous blood.
Fever, lid swelling, reduced eye mobility
You could see swollen veins on an ophthalmoscope
What muscle disorder could cause your eye to drift upward in the adducted position?
The obliques handle elevation/depression in the adducted position.
If the sup oblique is paralysed then the normal balance between it and the inf would be out. Causing the inf to elevate the eye when its adducted.
What is a coloboma? [3]
A hole in a part of the eye e.g. Iris/retina/optic disc [1] in the shape of a keyhole. [1]
Caused by failure of the choroidal fissure [1] to close during embryological development
Retinal detachment Presentation [4] Describe the type of loss of vision Risk factors [4] At what layer does a retinal detachment occur? [1]
4F’s
- Floaters
- Flashes
- Field loss
- Fall in acuity
Painless loss of vision, curtain falling over vision; the curtain falls down as the lower half of the retina detaches upwards
RF:
- Myopia (long eyeball)
- Ocular surgery
- Trauma
- FMH or other eye RD
Detachment usually occurs between the potential space between the 9th and 10th layers of the retina
How do blunt trauma retinal detachments occur? [3]
Ophthalmoscope appearance [2]
The force of the trauma is transmitted to the eye and it causes peripheral tears [1] in the retina and liquidation of the vitreous gel [1] It then pushes through the retinal tear and causes it to detach [1]
Grey opalescent retina ballooning forward
Define Ptosis [1] and its cause [2]?
Drooping of the Eyelid
Usually due to paralysis of the Levator Palpebrae Superioris [1] or damage to the oculomotor nerve [1]
What could cause an inability to close the eyelid? [2]
Paralysis of the facial nerve, often comes with an ear infection
What happens to the eye if you cant close your eyelid? [2]
The cornea dries out and ulcerates.
This is especially bad when your asleep
Define a Stye/Hordeolum? [2]
A small painful lump on the inside or outside of the eyelid [1] usually pus filled abscess from a bacterial infection [1]
What are the types of stye? [4]
External Stye (Or Hordeolum Externum) - Due to blockage of sebaceous glands at the base of the eyelashes
Internal Stye (Or Hordeolum Internum) - Blockage of meibomian glands in the tarsal plate
What do meibomian glands do? [1] Where are they located? [1]
They’re in the tarsal plate of the eyelid
They make the oily layer of tear film
How do we treat a Stye? [4]
Warm compress
Eyelid Hygiene
May need surgical incision and curettage (scooping out)
(An external Stye may be solved by removing the affected lash)
What are the causes of corneal ulcers? [5]
Inflammatory:
Infection
Trauma
Non-inflammatory:
Degenerative or dystrophy
Corneal dystrophy - clinical features [4]
Progressive group of eye disorders
Abnormal material accumulates in cornea
Opacification causing decrease in vision
Bilateral, non-inflammatory
Why is it easier to do a corneal transplant than any other?
The cornea is avascular
Therefore its less likely the body will notice and react to the foreign antigens of the transplant.
Therefore you don’t need the same degree of antigen matching and rejection is less common leading to it being called an “immune privileged” site
Cataract
Presentation [4]
Presentation in children [3]
Classification? [3]
Blurred vision
Bilateral causes gradual loss of vision - frequent spectacle changes
Dazzle esp in sunlight
+/- monocular diplopia
Children - squint, white pupil, nystagmus (infants)
- Nuclear: new layers of fibre added by ageing compress nucleus of lense
- Cortical: new fibres added to outside of lens with age and produce cortical spokes; may not cause problems until mature and affects vision
- Posterior sub capsular: opacities in central posterior cortex, typically due to steroids and progress faster (also cause classic glare from bright lights)
What do we call an immature cataract? [2] What would be seen on ophthalmoscope
Imaging of nuclear cataracts [2]
Where would you likely see dot opacities? [2]
Variable amount of opacification, present in certain areas of the lens. No red reflex or visible fundus
Nuclear cataracts: cortical spoke-like wedge shaped opacities
Dot opacities - more in DM, dystrophia myotonica
What could cause a secondary cataract? [3]
- Steroid induced (sub capsular cataract)
- Nuclear Sclerosis (age-related compaction of old lens fibers in the nucleus)
- Sutural + Zonular Cataracts (congenital, opacification occurs in utero)
What would you do to take a look at a cataract?
Prevention of cataracts [2]
Use sympathetic eye drops to trigger pupil dilation.
The cataract is much easier to see this way
- Use sunglasses
- Reduce oxidative stress esp in smokers eg vit C, caffeine
How would you treat a cataract? [3] Recovery time [1] Pre-op care [2] Post-op care [3] What medication can you prescribe instead of surgery to treat milder cases?
Day case surgery using LA [1]
Small incision surgery, phacoemulsion (ultrasound) [1] and intraocular lens implant [1]
Recovery - patient can usually return home same day with dressing for few hours.
Pre-op - ocular biometry to fit suitable lens implant. Goal to make patient emmetropic or slightly topic.
Post-op use ab and anti-inflammatory drops 3-6w, balance problems should settle in 2-3w
Milder cases> give mydriatic drops
How does glaucoma cause vision loss [3]
Describe triad of signs [3]
Blockage of drainage system of aqueous humor [1] leading to optic nerve neuropathy and tunnel vision loss [1]
Diagnosed by a triad of signs:
- Raised IOP
- Visual field Defects
- Optic Disc changes on Ophthalmoscopy
What are optic disc changes that can be seen in glaucoma on ophthalmoscopy, specifically POAG [2]
Who to screen for POAG? [3]
Screening tests [2]
Pale disc (atrophy)
Cup to disc ratio >50%
Vessel bayonetting and nasal displacement of vessels
Disc hemorrhage
Screen those high risk:
- > 35yo with positive FMH, African-Carribean
- Myopia
- Diabetic, thyroid eye disease
Screening tests:
- Multiple stimulus static visual field screening
- Serial imaging documenting optic disc cupping
Rx for glaucoma [6] - State class of agent, eg, MOA
How does a trabeculectomy help with glaucoma? Complication [3]
Rx
- PG analogues Latanoprost OD (Increase Aqueous humor drainage)
- Beta blockers timolol BD (Decrease Aqueous humor production)
- Alpha adrenergic agonists brimonidine (works both mechanisms)
- Carbonic anhydrase inhibitors dorzolamide (Blocks water entering eye -> decreased aqueous humour production)
- Miotics pilocarpine (decrease resistance to aqueous outflow)
- Sympathomimetic dipivefrin
Filtration surgery where pressure valve established at the limbus so aqueous can flow into conjunctival bleb) or drainage device
o Cx: early failure, hypotony, bleb leakage, infection
What are the two main types of glaucoma? [2]
Describe the presentation of each
POAG (primary open angle glaucoma)
- Gradual progressive peripheral visual field defects
- The angle is open
Closed Angle glaucoma
- Angle between iris and cornea too narrow leading to rapid increase in IOP
- Painful red eye
Management of POAG [2]
Explain how this method fixes the problem [3]
POAG
- Laser Trabeculoplasty (more for elderly)
- Trabeculectomy - a filtration surgery [1] that establishes a pressure valve at limbus [1] so aqueous can flow into conjunctival bleb [1]
- Treat contralateral eye same time prophylactically
Presentation of Acute closed angle glaucoma [4]
State one predisposing risk factor [1]
Management (describe in order of flow) [6]
Acute uniocular attack
Generally unwell; Headache, nausea, painful red eye
Precipitated blurred vision, haloes around lights at night
Eye feels hard
Risk factor: shallow anterior chamber, hypermetropia
Mx:
Pilocarpine + acetazolamide, Timolol stat
Analgesia, antiemetics
Admit then monitor IOP
Mannitol 20% IV
Topical steroids, antihypertensive drops
Peripheral iridectomy or surgical trabeculectomy
Causes of retinal detachment [3]
Incidence of post-op detachment?
- trauma
- tumour
- inflammatory/ infective chorioretinitis
post-op re-detachment in 5-10%
Retinal Detachment: how to advise the patient to rest?
Superior detachment
Inferior detachment
o Superior detachment: lie flat
o Inferior detachment: lie 30o head up
Investigation of Glaucoma [3]
Tonometry
Central corneal thickness measurement
Gonioscopy: peripheral anterior chamber measurements and depth assessments
Causes of closed angle glaucoma
• Primary: anatomical predisposition
• Secondary:
- arises from pathological processes e.g. traumatic haemorrhage pushing posterior chamber forwards (usually 40-60y/o, more common)
- mydriatic drops
Tunnel vision causes [6]
Concentric diminution of visual fields papilloedema glaucoma retinitis pigmentosa choroidoretinitis optic atrophy secondary to tabes dorsalis hysteria
Difference between retinal detachment and posterior vitreous detachment
Posterior vitreous detachment
- Flashes of light (photopsia) - in the peripheral field of vision
- Floaters, often on the temporal side of the central vision
Retinal detachment
- Tunnel vision loss
- A veil or curtain over the field of vision
- Straight lines appear curved
