hello there and welcome to the clinic so today i would like to show you this very
special poster this is disorders of the eye one of my personal
favorite posters that i've come across in the years of testing you may have seen it yourself
in your optometric consulting room and the reason why i like this poster so much is because
not only does it show you the normal features of the eye very well
which are nicely labeled but it also shows you some of the things that can go wrong around
or within the eye and today i'm just going to go through
the poster in a little bit more detail to help you relax and understand a little bit more about
the eye so i'm going to start with the normal eye anatomy we've taken almost a quarter slice
from the eye here to give you a good view of the retina almost cross sectional view here
of the eye so starting at the front the white part is the sclera
the coloured part of your eye which is the iris
and the hole in the center is your pupil for allowing light
to pass through and for the retina to capture the light and convert it into chemical energy
now here you have your focusing apparatus this is the crystalline lens here
attached to the ciliary body with the lens zonules here
now just back to the front of the anterior portion you have the cornea there
which should be the clear transparent window to the eye
externally we have the eye muscles here we just have two
on this diagram we have the superior rectus and the inferior rectus extraocular muscles
and then we have the retina we have the cross-sectional three layers here the sclera
the vascular choroidal layer and the retina itself
here you can see what looks like a little planet that is your optic nerve head
where the nerve fibers collect and travel all the way to the visual cortex
for perception a little slightly darker area here which is slightly more pigmented
than other areas of the retina this is the macula which is associated with
your central vision and then you have the veins and the retinal arteries nourishing
the ocular tissue and the veins draining the blood in this direction okay so that
is the cross sectional quarter slice of the eye we have another cross section here
a little close up of the retina and a zoomed in appearance of a normal optic
disc you can see there is your optic disc or your optic nerve head you have your veins
and you have your optic cup within the optic disc there and just as little fine
pale dashes that you see coming away they are the retinal nerve fibers there okay so looking at
this diagram here this is showing an exotropia and outward deviation of the left eye
you can see that little white spot in each eye
that is the corneal reflex so this eye is looking straight you can see that the corneal reflex
is in the center of the pupil the corneal reflex remains central
but because the eye is turning out the reflection on the cornea is here
and as you can see we would call this a left exotropia or a left divergent squint okay
we have the opposite here we have an esotropia you can see the left eye is turning in
the corneal reflex is not in the center of the pupil like this eye
so that's one of the things we look for your corneal reflexes
to see whether you have a deviation of the eye so we have an inward turn here a left esotropia
or a left convergent squint okay so we're going to look at my favorite part here i can have a look at
some more things that can go wrong with the eyes beautifully illustrated here so one of the things
we'll look at is whether you have some blepharitis the bacteria that lives on the lids is it causing
inflammation i'll be looking at the lid redness lit hyperemia by looking for any scales
flakes deposits on the lid margins upper and lower we'll also pay close attention
to the conjunctival surface looking for any involvement there and on the cornea of the eye
so that is one condition we could look for another common condition is conjunctivitis
inflammation of the conjunctival layer that covers the sclera there the transparent membrane
has this become inflamed so we'll be looking at the conjunctival redness
we'll be looking at the cornea for any involvement
we'll be looking for any discharge in the eye whether that's sticky like here
or any watering and we will also flip the upper lid have a look underneath
for any palpebral conjunctivitis as well as bulbar so that is conjunctivitis
now if our patient is diabetic we'll obviously be dilating the pupils
and we'll be having a look for anything related to the diabetes which if there
is we refer to as diabetic retinopathy so we're going to be looking for any exudates
any areas of ischemia shown by this cotton wool spot here
we'll be looking for any dot and blot hemorrhages on the retina in the more advanced cases
we'll be looking for any new vessel growth any neovascularization
any pre-retinal hemorrhages
venous beading
and anything else that comes along with diabetic retinopathy there
we'll also be looking at something that affects your macular region looking for any
macular degeneration here so we'll be looking for any waste products
such as these here which are drusen we're looking for any leakages here like this macular oedema
and for any hemorrhages in the macular area so that will certainly affect vision
if someone has wet macular degeneration and even dry macular can affect the vision so that's a
very important one there something very serious is ocular cancer so this is known as a melanoma
likely a choroidal melanoma growing within the originating within the choroidal
vascular layer here as you can see it's almost mottled
dark gray in appearance
so if you see one of these will be dilating your pupils getting a closer look looking
at the elevation using the volk lens and making a prompt
referral another condition you've heard of is glaucoma
raised intraocular pressure is the pressure of the eye causing damage
to the optic nerve head is there extra cupping compared to what we see in the normal here
do we see any vascular involvement such as bayoneting here
we will use the volk lens to check the depth of cupping we're looking at how pale the
optic nerve head and the neural retinal room appears i'll be looking at the lamina cribrosa
within the cup and for any splinter hemorrhages any peripapillary atrophy
to determine if your eye or eyes are suffering from glaucoma
so we'll also be checking the eye pressure
and the peripheral vision in the eyes to come to some kind of conclusion and if available
optometrists can also perform an oct scan to check cross-sectional appearance of the optic nerve
and check the thickness of the neural retinal rims
okay moving on something that is very common
in the population vitreous floaters so a little transparent or yellow opacities
within the jelly of the eye
moving around so what we must determine is if somebody has vitreous floaters
how long have they had them has there been a sudden increase in the amount of floaters
because if there's been a sudden increase or they've become larger quite quickly
this leads to something related here retinal detachment or retinal tear has the retina
detached or is there a rip in the retina that is accounting for an increase in quantity
and size of your vitreous floaters if we see no retinal pathology following dilation
and the patient's floaters are about the same if they haven't changed over the years
we'll note this on the record and just assume that they are normal vitreous floaters there
okay so they're very common i have them myself but as far as i'm aware i don't have any
retinal tear or detachment in my eyes and also with retinal detachment as well as an increase
in floater size and quantity the patient may be experiencing
flashing lights somewhere in their peripheral vision the floaters may appear as cobwebs
or the patient may be seeing a dark curtain or veil from any angle within the vision so that's
a very important condition to be looking out for it requires a good case history
in terms of asking about the floaters and any other symptoms associated with retinal tear or
detachment another very common condition we see in practice is cataract
okay so cataract develops within the crystalline lens so if we're focusing on age-related cataracts
over the years the crystalline lens can become
more opacified more blurry as you can see here the crystalline lens
has become quite foggy compared to the normal lens here and as light comes through the eye
it might be causing a little bit more blurred vision a little bit of light scatter
and glare for the patient and also as it slowly develops their colour perception
will potentially reduce and change so we will obviously check the vision we'll dilate the
pupils have a look at the cataract have a look beyond the cataract at the retina
obviously a cataract can obscure the view so we must dilate the pupils make it bigger and see
what's going on behind the cataract could there be some diabetes at the back of the eye could there
be some macular degeneration for example and if the cataract is causing problems to the patient
if their quality of life is reduced we might want to consider referring them for cataract
surgery so we can remove the cataract within the eye and place a little implant within the lens sac
and finally moving on to the more anterior part of the eye the cornea
was also looking for any corneal ulcers or any pathology that can affect the cornea so this is
where we can use our slit lamp we're looking for any ulcers or hypopyon in the anterior chamber
which is the pus accumulating there there is the peripheral ulcer
which would no doubt be causing the patient a significant amount of pain
discharge and eye redness potentially
looking for any inflammation of the cornea such as keratitis some infiltrates here
a little bit of corneal inflammation this is known as marginal keratitis
and another type of ulcer i'll be looking for is a herpes dendritic ulcer
which you can see stains with fluorescein and you get this almost branched
corneal ulcer appearance that must be dealt with promptly if that is spotted in the clinic
so i hope like me you've enjoyed learning a little bit more about the eye and the things we're
looking for as well as being able to understand the normal anatomical appearance of the eye
so that is disorders of the eye completed i'll see you again next time in the clinic