Opthalmoscopy Flashcards
What causes an absent red reflex?
Retinal blastoma
Retinal detachment
Cataract
How can a relative afferent pupil defect be picked up?
Swinging light test
- When light is shone on abnormal eye, the pupil appears to dilate, as there is reduced input to the brain from the abnormal eye, so both pupils dilate in the face of light being moved away from the normal eye
AKA Marcus Gunn
How can an efferent pupil defect be picked up?
Shine a light in one eye and it only causes contralateral constriction
What is anosocria?
Unequal pupil sizes - can be harmless
What is a cataract?
Painless opacification of the ocular lens due to buildup of protein and pigment, leading to gradual visual loss
A patient has decreased visual acuity, which improves after using a pinhole. What is the diagnosis?
Cataract (pinhole removes aberrations of light)
What is a Holmes-Adie pupil?
Large pupil that is slow to constrict to light - this can be normal
What causes cataract?
Congenital - intrauterine infection Diabetes Steroids Age Radiation therapy
What is a nuclear cataract?
Yellow/browning on centre of lens - associated with glare and myopia
What is a cortical cataract?
Wedge-like opacity that starts at the peripheries and works towards the centre
What is a sub capsular cataract?
Occurs at the back of the lens - associated with diabetes and steroids
How are cataracts managed?
- PHACOEMULSIFICATION - Ultrasonic device is used to break up and remove the cataract
- SURGERY - put artificial lens in, which doesn’t have the ability to accommodate
What is glaucoma?
Optic nerve change associated with raised intraocular pressure and associated visual field loss.
Characterised by optic disc changes
What is the pathology behind glaucoma?
- Problem with ocular drainage system
2. Excessive production of aqueous humour
What produces aqueous humour?
The ciliary body (also involved in accommodation)
What is open angle glaucoma and what are the RFs?
Reduced drainage of aqueous humour due to dysfunctional meshwork
RF: family history, trauma, age, steroids, race (african)
What is closed angle glaucoma?
Acute onset increased ocular pressure causing red eye, visual loss, vomiting, pain and seeing halos around lights. In this case the angle is completely closed, and no aqueous humour can leave
RF: asians, small eyes, big cataracts
What is golden application tonometry?
A machine used to measure intraocular pressure (in glaucoma for example)
What is the normal intraocular pressure?
10-20mmHg
What does a normal optic disc look like?
- Creamy pink colour
- Cup with small round central depression
- Symmetry between both eyes
- Well-defined edges
What is optical coherence tomography?
Imaging used to look at the retina and quantify optic nerve fibre loss
What is perimetry?
A visual field test which can pick up arcuate scotoma, caused by glaucoma
How is glaucoma managed medically?
Reduce aqueous humour production
- Topical b-blockers (timolol)
- ACE inhibitors (dorzolamide)
Increase fluid outflow
- Prostaglandin analogues (-prost these cause eyelash growth)
- Miotic agents (pilocarpin)
Dual mechanism
- Alpha agonists (-onidine)
How is glaucoma managed surgically?
Create a new drainage pathway:
- laser surgery
- trabeculectomy
- canaloplasty
- glaucoma implant devices
What are the stages of diabetic retinopathy?
Non-proliferative - dots, blots and exudate
Pre-proliferative - cotton wool spots, venous bleeding, looping
Proliferative - neovascularisation
End-stage - retinal detachment
Why do you get neovascularisation in proliferative retinopathy?
Microvascular changes cause occlusion and ischaemia. This stimulates the body to produce growth factors which lead to neovascularisation
Why do you get cotton wool spots in pre-proliferative retinopathy?
Loss of pericytes causes leakage and exudate.
What is maculopathy?
Retinopathy at the macula, causing exudate haemorrhages and micro-aneurysms
How is diabetic retinopathy managed?
- Pan-retinal photocoagulation
- Anti VEGF injections
- Focal laser (scars retina to reduce neovascularisation)
- Surgery
What is a side effect of focal laser treatment?
It causes visual field loss as you are scarring the retina
What are the features of hypertensive retinopathy?
AV nipping Copper/silver wiring (hardened arteries) Cotton wool spots Flame haemorrhage Papilloedema
How is hypertensive retinopathy treated?
Get BP down below 140/90
What is strabismus?
Squint
What is:
a) esotropia?
b) exotropia?
c) hypertropia?
d) hypotropia?
a) squint inwards
b) squint outwards
c) squint upwards
d) squint downwards
What would cause esotropia/hypertropia?
Esotropia - 6th nerve palsy
Hypertropia - 4th nerve palsy
