Visual Failure Flashcards
The commonest cause of visual dysfunction is a
________
simple refractive error.
The WHO defines blindness as ‘best visual acuity less than ______
3/60’,
in Australia eligibility for the blind pension is ‘bilateral corrected visual acuity less than _________ or significant visual field loss’ (e.g. a patient can have 6/6 vision but severely restricted fields caused by chronic open-angle glaucoma).
6/60
The commonest causes of sudden visual loss are
____ and ________
transient occlusion of the retinal artery (amaurosis
fugax) and migraine
‘Flashing lights’ are caused by traction on the
retina and may have a serious connotation: the
commonest cause is________
vitreoretinal traction, which is
a classic cause of retinal detachment.
The presence of floaters or ‘blobs’ in the visual
fields indicates pigment in the vitreous: causes
include _______ and _____
vitreous haemorrhage and vitreous detachment
______is the commonest
cause of the acute onset of floaters, especially with
advancing age
Posterior vitreous detachment
Retinal detachment has a tendency to occur in
________
short-sighted (myopic) people
Suspect a _________ where objects look
smaller or straight lines are bent or distorted.
macular abnormality
Central visual loss presents as
impairment of visual acuity and implies defective
_____ or __________
retinal image formation (through refractive error or
opacity in the ocular media) or macular or optic nerve
dysfunction
It is important to differentiate the central field
loss of macular degeneration from the _________
hemianopia of a CVA.
2 drugs which are oculotoxic
ethambutol and quinine/chloroquine
Questions specific Sx
Presence of floaters → normal ageing (especially
≥ 55 years) with posterior vitreous detachment
or may indicate _____ or ______
haemorrhages or choroiditis
Questions specific Sx
Flashing lights → normal ageing with posterior
vitreous detachment or indicates _______
traction on the
retinal
Questions specific Sx
Coloured haloes around lights → ____ and _____
glaucoma and cataract
Questions specific Sx
Zigzag lines → _________
migraine
Questions specific Sx
Vision worse at night or in dim light →
retinitis
pigmentosa, hysteria, syphilitic retinitis
Questions specific Sx
Headache → _____
temporal arteritis, migraine, benign intracranial hypertension
Questions specific Sx
_________ → macular disease, optic
neuritis
Central scotomata
Pain on moving eye → _________
retrobulbar neuritis
Distortion, micropsia (smaller), macropsia
(larger) → _________
macular degeneration
Visual field loss:
— central loss—_________
— total loss—______
— peripheral loss
macular disorder
arterial occlusion
It is worth noting that if a patient repeatedly
knocks into people and objects on a particular
side (including traffic accidents), a _________
bitemporal or homonymous hemianopia should be suspected
Almost half the causes of blindness are genetically determined, in contrast to the ____ and _______causes that predominate in third world countries.
nutritional and infective
About ________ of children will fail to develop proper vision in at least one eye.
3%
The eyes of all babies should be examined at birth
and at ________
6 weeks
______ is defined as a reduction in visual acuity due
to abnormal visual experience in early childhood.
Amblyopia
What is the cause of amblyopia
caused by interference with visual
development during the early months and years of life.
Common causes of amblyopia
- strabismus
- large refractive defect, especially hypermetropia
- congenital cataract
The two serious squints are the ______and
______ones, which require early referral.
Transient squint and latent squint (occurs under
stress e.g. fatigue) usually are not a problem
constant
alternating
Always refer children with strabismus (squint)
when first seen to exclude ocular pathology such as
retinoblastoma, congenital cataract and glaucoma,
which would require emergency surgery
The younger
the child, the easier it is to treat amblyopia; it may
be irreversible if first detected later than _____
school
age
Problems with cataracts in children
development of vision may be permanently impaired
amblyopia
Cataracts are diagnosed by looking at
the _______and this should be a routine part of the
examination of a young child
red reflex
Common conditions
causing cataracts are ____ and _____
but most causes are unknown.
genetic disorders and rubella
Refractive errors, with the error greater in one eye,
can cause _______
amblyopia
_______, although rare, is the commonest
intraocular tumour in childhood. It must be excluded
in any child presenting with a white pupil
Retinoblastoma
What reflex do RB patients have?
Such children also have the so-called ‘cat’s eye reflex’.
_______ in its various forms is
the commonest cause of visual deterioration in the
elderly
Macular degeneration
Most patients with a vision of ______
or worse in both eyes usually benefit from cataract
extraction, but some can cope with this level of vision
and rely on a good, well-placed (above and behind)
reading light
6/18
Sudden loss of vision in the elderly is suggestive
of__ and _______so this
problem should be checked
temporal arteritis or vascular embolism,
Pathophysio of devt of floaters
When the vitreous gel shrinks as part of the normal
ageing process, it tugs on the retina (rods and cones),
causing flashing lights. When the gel separates from
the retina, floaters (which may appear as dots, spots
or cobwebs) are seen
FLoates can also be soon in whom?
myopic or who have had eye surgery such
as removal of cataracts
In the normal eye (emmetropia) light rays from
infinity are brought to a focus on the retina by the
_______ (contributing about two-thirds of the eye’s
refractive power) and the ______(one-third).
cornea
lens
the cornea is very important in refraction and
abnormalities such as _____ may cause severe
refractive problems
keratoconus
The process of ________ is required for
focusing closer objects. This process, which relies on the
action of ciliary muscles and lens elasticity, is usually
affected by ageing,
accommodation
Highly myopic eyes may develop____ or _____
retinal detachment or macular degeneration.
Mx of Myopia
• Glasses with a concave lens
• Contact lenses
• Consider radial keratotomy or excimer laser
surgery
This condition is more susceptible to closed angle
glaucoma.
Hypermetropia (long-sightedness)
Hypermetropia (long-sightedness) is asstd with what condition in early childhood?
In early childhood it may be associated
with convergent strabismus (squint).
There is a need for near correction with loss of
accommodative power of the eye in the 40s. What condition?
Presbyopia
This creates the need for a corrective lens that is more
curved in one meridian than another because the
cornea does not have even curvature
Astigmatism
Cx of astigmatism
If uncorrected,
this may cause headaches of ocular origin
_______ is one cause of astigmatism.
Conical
cornea
If visual acuity is not
normalised by looking through a card with a 1 mm
pinhole, then the defective vision is not solely due to
a _______
refractive error.
The term ‘cataract’ describes any_________
lens opacity
Cataract causes gradual visual loss with
normal direct___________
pupillary light reflex
Causes of progressive B visual loss
From the globe: ________
Chronic glaucoma
Senile cataracts
Causes of progressive B visual loss
From the Retina: ________
Macular degeneration Retinal disease: • diabetic retinopathy • retinitis pigmentosa • choroidoretinitis
Causes of progressive B visual loss
From the Optic nerve
Optic neuropathies
Optic nerve compression (e.g.
aneurysm, glioma)
Toxic damage to optic nerves
Causes of progressive B visual loss
From the Optic chiasma
Chiasmal compression: pituitary
adenoma, craniopharyngioma, etc.
Causes of progressive B visual loss
From the Occipital cortex
Tumours
Degenerative conditions
The _______ is a reflection of the fundus when the
eye is viewed from a distance of about 60 cm (2 feet)
with the ophthalmoscope using a zero lens.
‘red reflex’
Contraindications for extraction of cataract include ____ and _____
intraocular inflammation and severe diabetic retinopathy
The removal of the cataractous lens requires
optical correction to restore vision and this is usually
performed with an __________
intraocular lens implant
For cataract, Complications are uncommon yet many patients may require _______ to clear any opacities that may develop behind the lens implant
YAG laser capsulotomy
What drugs can be given to post op cataract
— steroids (to reduce inflammation)
— antibiotics (to avoid infection)
— dilators (to prevent adhesions
Sunglasses, particularly those that wrap around and
filter UV light, may offer protection against ______
cataract
formation
_______ is the commonest cause of
irreversible blindness in middle age
Chronic simple glaucoma
Features of chronic glaucoma
- Familial tendency
- No early signs or symptoms
- Central vision usually normal
- Progressive restriction of visual field
Findings in glaucoma
Tonometry
• Upper limit of normal is_______ mmHg
Ophthalmoscopy
• Optic disc cupping ______ of total disc area
22
> 30%
Meds for glaucoma used for life
— timolol or betaxolol drops bd
What other drugs can be given for pts with glaucoma
— latanoprost drops, once daily
— pilocarpine drops qid
— dipivefrine drops bd
— acetazolamide (oral diuretics)
Primary degeneration of the retina is a hereditary
condition characterised by a degeneration of rods
and cones associated with displacement of melanincontaining cells from the pigment epithelium into the more superficial parts of the retina
Retinitis pigmentosa
Features of RP
- Begins as ______ in childhood
- Visual fields become_____
- Blind by _______
night blindness
concentrically narrowed (periphery to centre)
adolescence (sometimes up to middle age
What may delay progression of RP
Irreversible course—may be delayed by vitamin A
Ophtha findings of RP
• Irregular patches of dark pigment, especially at
periphery
• Optic atrophy
Pain and redness may be minimal with this chronic
inflammation. If untreated, visual loss often develops
from secondary glaucoma and cataract.
Chronic uveitis
ocular problem with chronic uveitis>
The pupil is bound to the lens by synechiae and is distorted
AIDS may have serious ocular complications, including 1 2 3
Kaposi sarcoma of the conjunctivae, retinal haemorrhage and vasculitis
Problem with HIVs
Another problem is ocular________, which presents as areas of opacification with haemorrhage
and exudates.
cytomegalovirus infection
_______ is transient loss of vision (partial or
complete) in one eye due to transient occlusion of a
retinal artery. It is painless and lasts less than 60 minutes
Amaurosis fugax
Amaurosis usually caused by an ______
embolus from an atheromatous carotid artery in the neck
In Aamurosis, The most common emboli are
______, which usually arise from an ulcerated
plaque
cholesterol emboli
Unilateral loss of vision provoked by activities such as
walking, bending or looking upwards is suggestive of
______
ocular ischaemia
What triggers ocular ischaemia?
It occurs in the presence of severe
extracranial vascular disease and may be triggered
by postural hypotension and stealing blood from the
retinal circulation.
What factors may cause RD
Retinal detachment may be caused by trauma, thin
retina (myopic people), previous surgery (e.g. cataract
operation), choroidal tumours, vitreous degeneration
or diabetic retinopathy
Classic eye sx of RD
‘A curtain came down over the eye’, grey cloud or
black spot
In RD, small holes are usually tx by?
Small holes treated with laser or freezing probe
What may cause vitreous hemorrhage
spontaneous rupture of vessels, avulsion of vessels during retinal traction or bleeding from abnormal new vessels
Associations of vitreous hemorrhage
Associations include ocular trauma, diabetic retinopathy, tumour and retinal detachment.
SSx of Vitreous hemorrhage
- Sudden onset of floaters or ‘blobs’ in vision
* May be sudden loss of vision
Ophthalmoscopy findings of Vitreous hemorrhage
Ophthalmoscopy may show reduced light reflex:
there may be clots of blood that move with the
vitreous (a black swirling cloud
Cause of CRAO
The cause is usually arterial obstruction by
atherosclerosis, thrombi or emboli
SSx of CRAO
• Sudden loss of vision like a ‘curtain descending’
in one eye
• Vision not improved with 1 mm pinhole
• Usually no light perception
Ophthalmoscopy findings of CRAO
- Initially normal
- May see retinal emboli
- Classic ‘red cherry spot’ at macula
Mx of CRAO within 30 mins:
massage globe digitally through closed eyelids
(use rhythmic direct digital pressure)—may
______
• rebreathe carbon dioxide (paper bag) or inhale
_______
dislodge embolus
special CO 2 mixture (carbogen)
Prognosis of CRAO
Prognosis is poor. Significant recovery is unlikely
unless treated immediately (within 30 minutes).
Factors which may lead to thrombosis
Thrombosis is associated with several possible
factors, such as hypertension, diabetes, anaemia,
glaucoma and hyperlipidaemia. It usually occurs in
elderly patients.
SSx of Central retinal vein thrombosis
• Sudden loss of central vision in one eye (if macula
involved): can be gradual over days
• Vision not improved with 1 mm pinhole
Opthalmoscopy findings of Central retinal vein thrombosis
Ophthalmoscopy shows swollen disc and multiple
retinal haemorrhages, ‘stormy sunset’ appearance
T or F,
In Central retinal vein thrombosis
No immediate treatment is effective
No immediate treatment is effective
In Central retinal vein thrombosis
_________may be necessary in later stages if
neovascularisation develops to prevent thrombotic
glaucoma.
Laser photocoagulation
2 types of macular degeneration:
1
2
There are two types: exudative or ‘wet’ (acute), and
pigmentary or ‘dry’ (slow onset).
________is caused by choroidal neovascular
membranes that develop under the retina of
the macular area and leak fluid or bleed. It is a
serious disorder
‘Wet’ MD
‘Dry’ MD (9 out of 10 cases of MD) develops
________ and usually ______
slowly and is always painless
Ssx of MD
- Sudden fading of central vision (see FIG 77.6 )
- Distortion of vision
- Straight lines may seem wavy and objects distorted
Visual fields of pts with MD
- Central vision eventually completely lost
* Peripheral fields normal
What can be seen in the Amsler grid in pts with MD
Use a grid pattern (Amsler chart): shows
distorted lines
Ophtalmoscopy findings of MD
- White exudates, haemorrhage in retina
* Macula may look normal or raised
What is the Tx for wet MD
For ‘wet’ MD refer urgently for treatment, which
is currently based on injection of antivascular
endothelial growth factor drugs (ranibizumab
or bevacizumab) into the vitreous humour
What is the Tx for dry MD
No treatment is available to stop or reverse MD
Age-Related Eye Disease Study provided confirmatory
evidence that the chronic pigmentation
type responds to free-radical treatment with the
antioxidants vitamins A, C, E, and zinc using betacarotene,
15 mg; vitamin C, 500 mg; vitamin E,
400 IU; and 80 mg zinc oxide
With _____________there is
a risk of sudden and often bilateral occlusion of the
short ciliary arteries supplying the optic nerves, with
or without central retinal artery involvement.
temporal arteritis (giant cell arteritis)
What vision is lost in pts with temporal arteritis
Sudden loss of central vision in one eye (central
scotoma)
Neuro PE of pts with temporal arteritis
Afferent pupil defect on affected side
Labs of pts with temporal arteritis
Usually elevated ESR >40 mm
Ophthalmoscopy findigs of temporal arteritis
Ophthalmoscopy shows optic disc swollen at first,
then atrophic. The disc may appear quite normal
Tx for temporal arteritis
• Immediate corticosteroids (60–100 mg
prednisolone daily for at least 1 week
In pts with temporal arteritis
What to do if there is a localised tender area)
Biopsy temporal artery
Migraine may present with symptoms of visual loss.
Associated headache and nausea may not be present
Retinal migraine
SSx of retinal migraine
- Zigzag lines or lights
* Multicoloured flashing lights
What condition
The vitreous body collapses and detaches from the
retina. It may lead to retinal detachment
Posterior vitreous detachment
Ssx of Posterior vitreous detachment
- Sudden onset of floaters
- Visual acuity usually normal
- Flashing lights indicate traction on the retina
Causes of Optic (retrobulbar) neuritis
Causes include multiple sclerosis, neurosyphilis and
toxins
What vision is lost in Optic (retrobulbar) neuritis
- Usually a central field loss (central scotoma)
* Afferent pupil defect on affected side
Ophtha findings of Optic (retrobulbar) neuritis
• Optic disc swollen if ‘inflammation’ anterior in
nerve
• Optic atrophy appears later
• Disc pallor is an invariable sequel
Patients with ________ typically suffer from
ocular pain or discomfort and reduced vision
corneal conditions
Inflammation of the cornea—keratitis—is caused by factors such as 1 2 3 4
ultraviolet light e.g. ‘arc eye’, herpes simplex, herpes zoster ophthalmicus and the dangerous ‘microbial keratitis
______ is an ophthalmological emergency that should be
considered in the contact lens wearer presenting
with pain and reduced vision.
Bacterial keratitis
Pittfalls
• Mistaking the coloured haloes of________for
migraine.
• Failing to appreciate the presence of retinal
detachment in the presence of______
glaucoma
minimal visual
impairment
Pittfalls
• Omitting to consider ______as a cause
of sudden visual failure in the elderly.
• Using eyedrops to dilate the pupil (for fundal
examination) in the presence of _______
temporal arteritis
glaucoma
Tonometry is advised routinely for all people over
______ years; those over 60 years should have tests
every 2 years
40
T or F
Any family history of glaucoma requires tonometry
at earliest age
T
Temporal arteritis is an important cause of _____
retinal artery occlusion
Suspect field defect due to ________ if
people are misjudging when driving.
chiasmal compression
Central retinal artery occlusion may be overcome
by ________
early rapid lowering of intraocular pressure
Keep in mind antioxidant therapy (vitamins and
minerals) for________
chronic macular degeneration
Consider _________ foremost if there is a
past history of transient visual failure, especially
with eye pain
multiple sclerosis
Considerations for the ff time scales
Sudden: less than 1 hour
Amaurosis fugax Central retinal artery occlusion Hemianopias from ischaemia (emboli) Migraine Vitreous haemorrhage Acute angle glaucoma Papilloedema
Considerations for the ff time scales
Within 24 hours
1
2
Central retinal vein occlusion
Hysteria
Considerations for the ff time scales
Less than 7 days
Retinal detachment
Optic neuritis
Acute macular problems
Considerations for the ff time scales
Up to several weeks (variable)
Choroiditis
Malignant hypertension
Considerations for the ff time scales
Gradual
Compression of visual pathways Chronic glaucoma Cataracts Diabetic maculopathy Retinitis pigmentosa Macular degeneration Refractive errors
