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
