block 6 - patient cases Flashcards
How can FA be used in helping to diagnose AMD?
FA is typically used to detect the presence of a choroidal neovascular membrane (CNVM) where this is not obvious by other techniques. Since these new vessels are leaky, FA will show a brighter area in the macula area if a CNVM is present.
what is fluorescein angiography?
the gold standard for assessing retinal circulation
why is oct angiography (A) starting to be used alongside (sometimes instead of) FA?
-noninvasive technique so no need for dyes to be injected
- provides a much higher resolution of the retinal and choroidal circulation
-quicker than FA
what are the two types of dyes used in FA?
sodium fluorescein and indocyanine green (much less common)
with the latter it is icca
in FA, what could hyper fluorescence indicate?
-leakages of blood vessels
-defects of the RPE
-oedema
in FA what could hypo fluorescence indicate?
partially or totally occluded blood vessels
why is NaF good for FA
it is water soluble with high fluorescence efficiency so:
-can highlight leaky vessels
-provide a high contrast so easy to be seen
watch and be able to identify the cranial nerve palsy videos
ok
what kind of deviation is heterotropia?
manifest
what is the prevalence of heterotropia
present in 2-4% of the population
what questions may you ask a patient with double vision?
- Double check monocular? (cover RE)
- Horizontal / vertical / diagonal / torsional?
- Constant / variable / intermittent / getting worse?
- Same in all directions (comitant vs incomitant)
- More noticeable at distance or near? muscle clues)
- Pain / discomfort?
look at slide 8 of case 6 full -> in person teaching session patient case 6 -> block 6
also check slides 13-21
okay
for a patient suspected of tropia, how can you justify measuring monocular VA?
check if va is worse in the suspected eye
for a patient suspected of tropia, how can you justify measuring cover test?
allows you to quantify the tropia
for a patient suspected of tropia, how can you justify doing an internal eye examination?
so you can check the disks
for a patient suspected of tropia, how can you justify measuring pupil responses
to measure anisocoria and to check perrla for potential rapd
what signs and their corresponding muscles will mean a patient has a 3rd cranial nerve palsy?
-ptsois (levator muscle defective)
-absent adduction (MR defective)
-vertical abnormalities (SR, IR and IO) defective
-mydriasis on affected side (pupil
what is the most common cause of 3rd cranial nerve palsy in older patients?
most common being vascular cause
give an example of what a partial 3rd CV palsy is
where it can only affect the superior muscles or only affect the inferior muscles or maybe when just one muscle is affected e.g. medial rectus so the patient wont present with all the symptoms but still have a 3rd nerve palsy.
what variations of 3rd CN palsy are there?
-complete
-pupil sparing
-partial (superior division)
-partial (inferior division)
-individual muscles innervated by CN 3
what is complete CN 3 palsy
where Levator palpebrae superioris, pupil, MR, SR, IR and IO are allm involved
what is pupil sparing CN 3 palsy
where all muscles are involved but the pupil function is normal
what is partial cn 3 palsy in superior division?
where SR and levator palpebrae superioris only are affected
what is partial CN 3 palsy in the inferior division
where IR, MR IO, pupil and ciliary muscle are involved
how do you manage CN 3 palsy?
new onset can have serios underlying health conditions - urgent referral to secondary care
what are the congenital causes of EOM dyscunction?
- Neurogenic
- Mechanical
- Myogenic
- Trauma (gestational /delivery)
- Other
what are the acquired causes of EOM dysfucntion?
- Neurogenic
- Mechanical
- Myogenic
- Trauma
what are the signs of a 4th nerve palsy (in the right side)
-right hypertropia
-AHP where head tilted left, chin down and face turn left
what are the signs of a left 6th nerve palsy?
-esotropia on the affected side
-maximum laevoversion
-ahp of face turn left
what happens to the eyes in duane’s retraction syndrome?
both lateral and medial rectus retract so when the patient looks right, the eyes seem to be pulled back into their socket.
what are the signs of right Brown’s syndrome?
-Limited elevation of the eye in an adduction
-Mechanical restriction of the superior oblique tendon
-Looks like inferior oblique palsy
-Hypotropia in primary position
what are a and v patterns and how common are they?
where horizontal deviation varies in up and down gaze and affect 25% of the population
what is the A pattern?
where there’s 10 diopters more convergence in upgaze compared to primary position
what is V pattern?
where there’s 15 diopters more divergence in down gaze compared to primary position
what other patterns are there as well as A and V patterns?
X, Y and lambda patterns
what causes A and V patterns?
-abnormal horizontal/ vertical muscle action
-anatomical variations affecting muscle action
-abnormal muscle innervation
-variations in muscle insertions
how can you manage A and V patterns?
usually asymptomatic so dont need any management but it there are large symptoms like a big ahp or diplopia then you can refer for surgery
When is an abnormal head posture usually found?
usually in people with incomitant deviations and are rare in comitant deviations
why may some people develop AHPs?
-replaces lack of movement in the paretic eye by moving the head instead
-improves ease of fusion and reduction in diplopia
so overall improves BV potential
this is because the field would otherwise be asymmetrical due to the restricted eye movement
(occasionally, AHPs can increase diplopia)
are ahps found in old or new deviations?
both
how do you know if a patient has eso or exo tropia depending on their head turn?
esotropia - head is turned to the same side so to the right (to abduct the good eye)
exotropia - head is turned to the opposite side so to the left (to adduct the good eye)
how do you know if a patients head tilt means they have an excyclo or incylco tropia?
for excyclotropia - head tilts to opposite side - head tilt left - to bring the defective eye to vertical
for incyclotropia - head tilts to the same side - head tilts to the right
- to bring the defective eye to vertical
how do you know what vertical tropia a patient has by looking at their ahps?
chin down = hypertropia
chin up = hypotropia
what is muscle sequelae?
where patients with a cranial nerve palsy with time end up with changes in the actions of other muscles that control the eye movement due to sherrington’s and herring’s law - more obvious than others in some patients.
what is the pattern of development for muscle sequelae in order?
Say you want to turn your right eye out, there’s increased innervation to the eye that does not want to turn out and the contralateral synergist muscle overacts due to equal innervation (hering’s law)
Over time, you get an overaction in the ipsilateral antagonist due to sherrington’s law
Underaction of contralateral antagonist - (Hering’s law and Sherrington’s law)
What is infantile esotropia?
An esotropia that is constant by 6 months of age.
what is fully accommodative esotropia? What is the underlying cause?
An esotropia that is acquired, is either constant or intermittent
(before treatment), which is straightened by correcting the associated
hypermetropia.
uncorrected hypermetropia
how can you treat fully accommodative esotropia?
-Full Cycloplegic hypermetropic correction
-Orthoptic treatment to expand base in fusion range
what is non accommodative esotropia? What age does it present in?
-An esodeviation occurs after 6 months of age that is not improved
with hypermetropia correction.
-2-5 years old
what is convergence excess esotropia?
An intermittent esotropia with binocular single vision present at
distance fixation but esotropia on accommodation for near fixation.
when may you do surgery on a case of convergence excess esotropia?
if there is:
-Reducing binocularity at near
-Reducing control with other forms of treatment (e.g. bifocals)
-Parent/Doctor preference over other treatments (e.g. bifocals).
-Orthoptic exercises not progressing.
-Consider prism adaptation to the near angle
what are the treatment options for convergence excess esotropia?
-Full cycloplegic hypermetropic correction -where present
-Bifocal glasses – split pupil
-Orthoptic exercises
-Miotics
-Surgery
what is age of onsent of intermittent distance exotropia?
between 2-4 years old
how is CCT related to the risk of glaucoma?
“Thin” corneas (≤555μm) are associated with an increased risk of glaucoma.
“Thick” corneas (>588μm) appear to protect against glaucoma.
steps to perform pachymetry
Tell the patient you are going to measure the thickness of their cornea
Gain consent to instill anaesthetic drops
Put in the dops
Sterilise the tip of the probe with an alcohol wipe
Dry it off with a tissue
Get the patient to look down
Lift their top lid up
The machine will beep as it takes measurements and when it beeps three times its done
Press and hold the up and down arrows for a few secs to take a new reading
Press and release the action button and you will hear two high pitched beeps which mean the device is ready
Up and down arrows let you scroll through other readings
Reading with a star indicates the reading furthest away from the average
what conditions can wide field pachymetry be used to assess?
-corneal thinning diseases like keratoconus
-corneal swelling diseases like fuch’s dystrophy = diagnosis, monitoring and assessment
what can wide field pachymetry be used for in assessment of keratoconus?
Diagnosis and monitoring, ensuring minimum corneal thickness before cross-linking treatment
what does gonioscopy allow you to do?
assess the anterior chamber angle - gold standard technique to assess when you suspect a narrow angle (grade II or below in van herrick)
what is sampolesi’s line?
when the demarcation line at the termination of Descemet’s membrane is pigmented
when may the trabecular meshwork appear black?
naturally darkens with age but may appear black in pigment dispersion syndrome and pseudoexfoliation syndrome.
what is the scleral spur and what does it look like?
it is the slight protrusion of the anterior portion of the sclera into the anterior chamber and shows up as a bright white line
when may the canal of schlemm be visible? How may this arise?
if its filled with blood (so looks pink).
-prolonged gonioscopy exam
-if excessive pressure has been applied to the eye
what patients should you avoid doing gonioscopy on?
-Recent ocular trauma, especially in the presence of hyphaemia or microhyphaema.
-Recent intraocular surgery, including cataract surgery.
what is a good question to start history and symptoms for a small child?
asking the parent whether anything and if so what it is that concerns them about their child’s vision
what is the new question you now have to ask in H and S for childeren in wales as of feb 2025?
You have to ask children under 16 how much time each day they spend outdoors each day as it is important to get info on myopia management and you have to record the answer that you do/dont have to this question
more time outdoors = lower likelihood of myopia
what should you do at the end of the history and symptoms especially for childeren?
do a summary just to check everything is correct/ has been covered and as the patient/ parent id there is anything else they want to find out today
from a picture, how can you figure out if a patient has a head tilt or a vertical tropia?
draw a line canthus to canthus and then make it go up to the corneal reflexes, then if it goes through the corneal reflexes, it means they are on the same plane hence there is no vertical deviation
when does amblyopia occur?
when the connection between the eye and the brain are disrupted in the first few years of life (before age 7)
what are the three causes of ablyopia?
- Strabismus/Strabismic amblyopia
- Refractive amblyopia
- Deprivation amblyopia (least common but most severe)
why is constant strabismus more likely to result with amblyopia than intermittent?
because Strabismic amblyopia is where there is binocular misalignment of the eyes meaning the patient ends up with double vision but over time, the brain suppresses the eye turning in but you lose binocular vision which means the other eye cannot develop normally whereas in intermittent, the turn is not constant which means suppression is not constant as there are periods of time where the image is single giving a better chance of BSV to develop
which horizontal tropia is more likely to cause amblyopia and why?
esotropia is more likely to cause amblyopia than exotropia because
with esotropia, the images overlap whereas with exo, there’s no overlap of images so no double vision so there’s no need for suppression
what is refractive amblyopia? what causes it?
where the non amblyopic eye has clear vision and the amblyopic eye has a higher refractive error and this is due to aniseikonia
when is anisometropic amblyopia more likley?
1.00–1.50 D or more anisohypermetropia
2.00 D or more anisoastigmatism
3.00–4.00 D or more anisomyopia.
what refractive errors can bilateral amblyopia occur?
5.00–6.00 D or more of myopia
4.00–5.00 D or more of hyperopia
2.00–3.00 D or more of astigmatism.
what is meridional amblyopia?
amblyopia caused by significant astigmatism
what causes deprivation amblyopia and give examples
caused by the visual axis being obstructed e.g.
Ptosis
Corneal opacity
Cataract
Vitreous haemorrhage
what can myopic shift cause?
(can be seen in teenagers) can cause a lazy eye to become the less myopic eye
what may be the best method to test a child’s accommodation?
dynamic ret as they probably will not understand what they have to do for AoA
what kind of test is best to check a child’s VA?
its always best to use letters so check with them/ parent that they know their letters instead of just assuming. Otherwise do a crowded letter test
what are the advantages of static ret?
- Quick and easy to perform
- No need for pharmacological agents
what are the disadvantages of static ret on children?
Not being able to fully relax their accommodation
Not being able to get them to focus on the distant target without losing concentration
in cycloplegic refraction in children what do you need to remember to do after you have refracted them?
you should take away half a diopter to account for refractive tonus, otherwise you may end up overcorrecting them and in children, being left overcorrected for a time can leave their vision foggy.
what are the advantages of cycloplegic refraction?
-provides acurate measurement of refractive error without accommodation interference
-* Allows for a better view of the fundus
* Gold standard for young children with strabismus
what are the negatives of cycloplegic refraction in childeren?
- Requires the use of pharmacological agents, which may have side effects
- Need to allow time for drops to work (30 mins)
- Requires parental consent
- May cause temporary discomfort or blurred vision for the child (can be over 24 hours)
- Child’s cooperation influences feasibility
- Darker irises may need more cyclopentolate and longer to
work
what kind of age groups is mohindra ret used in?
primarily infants and young childeren
what are the advantages of mohindra ret?
- Non-invasive, no need for pharmacological agents so is a good alternative when cycloplegia is not possible
- Suitable for very young children
- Minimises accommodation without drops
what are the disadvantages for mohindra ret?
- Requires a dark room
- May be less accurate due to partial accommodation relaxation
- Child may be uncooperative in a dark environment which influences the result
what are the advantages of autorefraction on young children?
-can be quick and easy
-provides a rough estimate of the prescription so can give a good starting point
what are the disadvantages of autorefraction on young childeren?
- May be unreliable due to accommodation and difficulty in
maintaining focus so still needs to be validated with ret - Child may not sit still for the test
what is the gold standard refraction for children based on the college guidelines?
cycloplegic refraction
what strategies should you take up when putting in cycloplegics for a child?
-best not to do it on their first appointment/ eye test so they don’t associate the opticians with a bad experience
-ask someone else to put the drops in for you as they sting so prevents the child associating you with the pain making them less likely to cooperate
-dont do it on their first appointment as by then the child may be tired
-dont do it on the first appointment as that way the parent can be prepared for the 20 mins waiting time by having something to do.
what should you tell parents before insertion of cycloplegic drops?
-explain why we need to instill the drops and their effects
-advise the parents of the potential adverse reactions before they are instilled and that the risk of these is very low
-you can give a leaflet to the parents from the college and make sure to record if you have given it
what might the eye hospital do if patching complaince is poor in childeren?
they may use atropine
What is Infantile Esotropia?
A convergent squint developing within the first 6 months of life, also known as congenital esotropia.
What causes Infantile Esotropia?
Unknown, but linked to family history, premature birth, developmental delays, seizure disorders, or hydrocephalus.
What are the features of Infantile Esotropia?
Large angle squint
Cross fixation
Equal vision in both eyes
Mild long-sightedness
Upward drift of eyes
Sometimes nystagmus
: What are the treatment goals for Infantile Esotropia?
Realign eyes
Restore some form of stereopsis (3D vision)
Ensure equal vision in both eyes
What are the treatment methods for Infantile Esotropia?
surgery to weaken inner muscles
Botulinum toxin (Botox) injections
Regular follow-ups
What are the complications of Infantile Esotropia?
Over or under correction of the squint
Further surgery or Botox treatment may be needed if alignment is not achieved
What is Accommodative Esotropia?
A convergent squint developing between 18-36 months of age.
What causes Accommodative Esotropia?
Long-sightedness causing excessive focusing and convergence.
What are the features of Accommodative Esotropia?
Long-sightedness
Alternating squint
Amblyopia (lazy eye)
Upward drift of eyes
What are the treatment goals for Accommodative Esotropia?
Correct refractive error
Treat amblyopia
Restore stereopsis
Improve appearance of squint
What are the treatment methods for Accommodative Esotropia?
Full-time spectacle wear
Occlusion therapy
Prisms
Surgery
What are the complications of Accommodative Esotropia?
Over or under correction of the squint
Further surgery may be needed if alignment is not achieved
What is Non-Accommodative Esotropia?
A convergent squint not related to focusing effort and does not change with glasses.
What causes Non-Accommodative Esotropia?
Often unknown, not linked to refractive errors
What are the features of Non-Accommodative Esotropia?
Convergent squint
No change with glasses
What are the treatment goals for Non-Accommodative Esotropia?
Align eyes
Improve appearance of squint
What are the treatment methods for Non-Accommodative Esotropia?
Surgery
Regular monitoring
What are the complications of Non-Accommodative Esotropia?
-Over or under correction of the squint
-Further surgery may be needed if alignment is not achieved
What is Intermittent Distance Exotropia?
The most common form of exotropia in childhood, where one eye diverges when looking at distant objects.
What causes Intermittent Distance Exotropia?
often unknown
What are the features of Intermittent Distance Exotropia?
Divergence of one eye
Good stereopsis
Rare amblyopia
What are the treatment methods for Intermittent Distance Exotropia?
Glasses
Patching
Eye exercises
Surgery
What are the complications of Intermittent Distance Exotropia?
-Over or under correction of the squint
-Further treatment may be needed if alignment is not achieved
what ages should children in the UK have an eye test
between age 4 and 5 and in wales, parents are sent a letter advising to get a WGOS sight test, sometimes parents need to be reminded that it is free
for lateral rectus dysfunction, what is the cause?
6th cranial nerve palsy
what are the signs of a 6th cranial nerve palsy?
(dysfunction of the LR)
-Esotropia on the affected side, more noticeable at distance than at near because the lateral rectus diverges the eye
-uncrossed diplopia - max on the same side as the affected eye e.g. rLR will have max diplopia on dextroversion (looking to the right)
-AHP of right face turn if its the rLR
for medial rectus dysfunction, what will the patient exhibit?
-Exotropia on the affected side, more noticeable at near than distance as medial rectus normally converges the eyes
-Crossed diplopia and the diplopia will be most on laevoversion (looking to the left)
-Ahp of left face turn if its the rMR
for right superior rectus dysfunction, what will the patient exhibit?
-Right hypotropia most noticeable in abduction as this is where the superior rectus is most active
-Patient may also have exodeviation as well as excyclotorsion but may not be visible in cover test
-Patient will report vertical diplopia with right image above left may also be crossed and maybe tilted. Most obvious in dextroelevation (when the px is looking up and right)
-Patient will adopt AHPs of chin pointed up, head tilt right and face turn right
for right inferior rectus dysfunction, what will the patient exhibit?
-Patient has a right hypertropia greater at distance than near
-Patient may also have exodeviation and incyclotorsion (but the latter may not always be visible)
-Vertical diplopia with left image above the right - greatest on dextrodepression, may be crossed and tilted
-Ahp would be chin down, head tilt right and face turn right
what are the signs of a 4th cranial nerve palsy?
(underaction of the right superior oblique muscle?)
-Right hypertropia more obvious at near than at distance
-Just looking at the patient you may see an excyclotorsion
-May have an eso deviation especially on CT
-Diplopia vertical, with the left image over the right, tilted and crossed and greatest in laevo depression (down and right)
-Ahp of head tilt left, chin down and face turn left
what are the signs of underaction of the right inferior oblique?
-Right hypotropia greater at near than at distance
-Might be able to see incyclotorsion just by looking at the patient
-May have an esodeviation especially on CT
-Vertical diplopia where right image is above the left image, image is uncrossed and tilted and greatest in laevoversion (up and right)
-Ahp of head tilt right, chin up and face turn left
Who are orthoptic exercises most useful for?
patients with exo-deviations and convergence insufficiency
less effective for vertical and eso deviations
what are the drawbacks to orthoptic exercises?
- Requires co-operation & discipline
- May be a bit uncomfortable
- Takes a few weeks for results to be seen
what orthoptic exercises can you use to improve convergence?
-pen to nose (useful to have an observer to make sure patient is converging correctly)
-jump vergence
-dot cards
-stereograms
then encourage patients to relax (by closing eyes or looking at distance objects) during and after to prevent spasm - so relaxing accommodation
how is pen to nose orthoptic exercise done?
- Start with pen about 50 cm away
- Steadily bring towards nose
- Patient encouraged to keep the pen single for as long as possible and to try to regain SV if it becomes double
(similar to NPC)
how is jump vergence orthoptic exercise done?
- Patient switches between a near object (as close as they can converge)
- Switches between a distant and the near object
- Each time they must ensure it is clear and single before switching distance
how is dot card orthoptic exercise done?
- hold card pointing down slightly
- starting with the furthest dot, make it single to see a V shape with the point furthest away
- progressively look at closer dots and hold each for a few secs and should see an X
- closest dot should give a V with the point closest to you
how do stereograms work as an orthoptic exercise?
- Card at 40cm
- Hold pencil at 20cm
- Looks at pencil – creates physiological diplopia
- Adjust position of pencil to align, then fuse cats – should appreciate depth in the central cat
- Encourages convergence (viewing pencil) but with less accommodation (to keep cats clear)
