common and chronic conditions Flashcards
leading causes of vision loss
ARMD, refractive error, cataract, diabetic retinopathy
what is refractive error
light is focussed inaccurately onto the retina, due to the size and shape of the eye
myopia is when
eye ball is too long / high corneal curvature
focus is in front of the retina
short sightedness, more common
hypermetropia is when
long sightedness
eyeball is too short or the corneal curvative is less
focus is behind the retina
how do you correct myopia
correct with a concave lens to unbend the light and correct for high corneal curvature or long eye
presbyopia
> 40yo
gradual loss of accomodation reflex
often at work using screens
discomfort, headache, blurriness, eye strain at work
how do you correct hypermetropia
convex lens
refractive error Hx
blurred vision at a distance (driving, TV), near (reading, screens) or both.
presbyopia: ~40yo, discomfort, headache, blurriness at work (eye strain)
aetiology or refractive error
myopia and hypermetropia: axial length and/or corneal curvature
presbyopia: loss of accomodation
astigmatism
irregular corneal curvature
examination of refractive error
improvement in VA with pin-hole occlusion (difficult in some patients)
get them to keep distance glasses on
management of refractive error
glasses/contacts (optometry), refractive surgery (ophthalmology)
drivers advice
presbyopes: 20-20-20 rule. lubricating drops
children: 20-20-2 rule, low dose atropine (ophthalmology)
presbyopia 20-20-20 rule
every 20 minutes, look 20 metres in the distance for 20 seconds
plus lubricating drops
kids 20-20-2 rule
2 hours spent outdoor every day to prevent myopia
plus low dose atropine (for a paediatric opthalmologist to consider in kids developing myopia)
a cataract is
an opacity of the natural lens
the lens should be transparent
symptoms of cataract
blur
diminish in brightness
glare in some subtypes of cataract
cataracts can be brought on my
systemic steroid use
diabetes
aging
cataract surgery
removal of the natural lens under anaesthetised eye
under local anaesthetic
ultrasonic probe used
laser can be used but often isn’t - primarily an ultrasound based surgery
artificial lens tailored to the patients eye replaces the natural lens
Hx of cataract
> 60 year olds
gradual blurring of distance vision
‘glasses seem smudged’
‘second sight’ = myopic shift causes people to be able to read better than before
glare, monocular diplopia
second sight
happens in cataract
caused by myopic shift
patient can paradoxically read/see close up better than they could before
aetiology of cataracts
age- related opacification of the natural lens fibres (protein denaturation)
others: congenital, traumatic, iatrogenic (steroids), diabetes, UV radiation
examination of cataract
progression of clear lens to yellow, brown, or white
slit lamp: nuclear, cortical or posterior sub capsular
management of cataract
address refractive error and dry eye first, this can often defer surgery
cataract surgery: day surgery, LAS (local anaesthetic sedation), painless, sequential; >90% success, recovery in days, dry eye symptoms post-op, may still need glasses
will you need glasses after cateract surgery
maybe - advise patients they may still need it
glaucoma is
a group of conditions characterised by progressive optic neuropathy, often linked to increased intraoccqular pressure (but not all glaucoma has increased intraoccqular pressure)
ow does glaucoma present
peripheral field vision loss
eventually leading to tunnel vision
Hx of primary open angle glaucoma
usually asymptomatic, may present late with field constriction or blurred vision
risk factors: +/- family history, age >40yo, obstructive sleep apnea, myopia, diabetes
risk factors of primary open angle glaucoma
risk factors: +/- family history, age >40yo, obstructive sleep apnea, myopia, diabetes
aetiology of primary open angle glaucoma
reduced aqueous outflow and raised IOP -> altered optic nerve head perfusion and progressive loss of retinal ganglion cells
examination of primary open angle glaucoma
raised IOP (>21 mmHg)
visual field loss
optic disc cupping or asymmetry worsening over time over serial measurements
normal anterior chamber depth and appearance
management of glaucoma
screening: 1-2 yearly with ophthalmology or optometry (at risk patients)
medical: b-blockers (e.g. timoptol), prostaglandin analogues, (Xalatan), alpha-agonsits (e.g. alphagan), carbonic anyhydrase inhibitors (e.g. Azopt)
surgical: SLT laser, trabeculectomy, glaucoma drainage devices
drusen looks like
kinda looks like hard exudate but its not
this is age related macula degeneration
drusen - deposits of protein and fat at the back of the eye that are waste products not being adequately pumped out of the retina because the ability to pump waste product out of the retina reduces with age
what is age related macula degeneration
progressive degeneration (wear and tear) of the macula, affecting central vision
pathophysiology of ARMD
degeneration of outer retina leading to drusen formation and photoreceptor loss
Hx of age related macula degernation
gradual central blurring, distortion (over months/years), prolonged dark adaptation
+/- smoking
family history, metabolic/cardiovascular disease
60-70+ yo
what is prolonged dark adaptation
eyes take too long to acclimate to the dark
examination of age related macula degeneration
macular drusen (yellow), pigment (black)
if you see red this is blood and this may be indicative of neo vascular age related macula degeneration which has a more subacute onset than ARMD
management of ARMD
routine ophthalmology referral
conservative management to slow progression
diet rich in green leafy vegetables, antioxidants, Mediterranean diet
supplimentation
stop smoking
self monitoring with amsler grid
how to monitor ARMD
use amsler grid chart at home
monitor for new distortion of new scotoma which is dry ARMD changing to wet
sooner wet is caught the better
