Examination of the eyes and vision assessment Flashcards
When performing an eye exam, you can break it down into several parts (or components). What are they?
Inspection of the eyes
Visual acuity
Visual fields
Visual reflexes
Movement of the eyes (extraocular muscles)
Fundoscopy (also called ‘ophthalmoscopy’)
What equipment do you want to collect before you conduct an eye examination on a patient?
Inspection - no tools needed
Visual acuity - snellen chart, ishihara plate, pinhole occluder, fine print reading chart (just an article)
Visual field - hatpin (white if performed on a non-white background, black if performed on a white background, and red to test for blindspot)
Visual reflex - pen torch
Fundoscopy - ophthalmoscope, mydriatic eye drops
Just like any other examination, you always start off with introduction and confirmation of patient details, then you explain what the procedure involves and finally you gain consent
What would you say to the patient regarding what the examination will involve?
“Hello, Grace, I would like to examine your eyes and test your vision today if that’s okay. It will involve me getting you to read some letters off a chart to test your the sharpness of your vision, shining lights to test the reflexes in your eyes, and some other tests that assess your visual fields and eye movements. I will also be using this device to examine both the interior and exterior of the eyes if that’s okay with you.”
“Are you happy for me to proceed?”
“Do you have any pain before we start?”
Wash hands!
Inspection of the eyes:
What are you looking for?
Eyes inspection:
To inspect the external eye, ask the patient to focus on a fixed object in the distance e.g. a light switch and use the fundoscope to carefully examine the eyelids, eyelashes, conjunctiva, sclera, cornea, iris and pupil
-
Eyelids
- Lumps - stye, meibomian cyst
- Swelling/ oedema - periorbital cellulitis, orbital cellulitis, Graves’ disease, allergies/ anaphylaxis (angioedema), infections, blepharitis
- Crusting and inflamed lid margins –> blepharitis
- Entropion - lower eyelid drooping and turned inwards so the eyelashes rub against the eyeball, causing discomfort
- Ectropion - lower eyelid drooping and turned outwards, causing eye dryness, excessive tearing and irritation
- _*Ptosis_
- Unilateral - CN3 palsy (complete ptosis), Horner’s syndrome (partial ptosis) - both affect ipsilateral side
- Bilateral - myasthenia gravis (fatiguability of eyes after peiods of activity and slow improve after periods of rest), myotonic dystrophy (autosomal dominant myopathy, of which there are 2 types: DM1 and DM2)
-
Eyelashes
- Any loss of eyelashes –> malignancy, post-chemo
- Trichiasis - eyelashes grow back towards the eye, irritating the cornea or the conjunctiva
- _*Diffuse conjunctival injection (redness)_
- Bacterial, viral and allergic conjunctivits
- _*Circumciliary injection_
- Dilated inflamed blood vessels centred around the limbus in a circular pattern –> disorders of deeper tissues and intraocular structures e.g. episcleritis, scleritis, keratitis, iritis, uveitis, acute angle-closure glaucoma
- _*Discharge_
- Watery discharge –> allergic conjunctivitis, viral conjunctivitis, or normal physiological response to e.g. corneal abrasion/ FB
- Purulent discharge –> bacterial conjunctivitis
-
Hyphema (quite painful)
- Pooling or collection of blood inside the anterior chamber of the eye. The blood may cover most or all of the iris and the pupil, blocking vision partially or completely
- Caused by trauma
-
Hypopyon
- Pus sitting at the bottom of the iris in the anterior chamber
- Seen in anterior uveitis, endophthalmitis, severe corneal ulcers
-
Periorbital erythema and swelling
- Seen in preseptal/ periorbital cellulitis (anterior to the orbital septum) or orbital cellulitis (posterior to the orbital septum)
- _*Pupil size and symmetry (asymmetrical pupils = anisocoria)_
- Normal adult pupil size ranges from 2-4 mm in diameter in bright light to 4-8 mm in the dark and both pupils are generally equal in size i.e. symmetrical
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Unilateral dilated pupil –> mydriatic eyedrops (anticholinergics), CN3 palsy (uncal herniation secondary to raised ICP), Holmes-Adie pupil, acute glaucoma, anterior uveitis (due to posterior synechiae), defect in efferent pathway, trauma
- Causes of CN3 palsy - brain tumour, haemorrhage, cavernous sinus thrombosis, vascular problems e.g. diabetes, HTN and atherosclerosis (less blood supplying the CN3 causing microvascular infarction), aneurysm in posterior communicating artery of the Circle of Willis
- Unilateral constricted pupil –> miotic eye drops (cholinergics) , Horner’s syndrome (always affects ipsilateral side)
-
Corneal abrasion
- Pain, redness, watering, photophobia, visual acuity maybe reduced
- Stain brightly with fluorescein drops and a cobalt blue light
-
Corneal ulcer
- Pain, watering, photophobia, and a staining epithelial defect with associated haziness (appear white and fluffy)
-
Foreign bodies
- Maybe visible on the surface of the eye or embedded within the cornea or sclera
- Pain, redness, watering, ‘FB sensation’
- _*Strabismus_ (misalignment of the eyes)
- Causes include CN6 palsy (–> esotropia, diplopia), CN3 palsy (“down and out pupil”at resting gaze, complete ptosis, mydraisis, diplopia), CN4 palsy (‘Up and in pupil” at resting gaze, head tilt towards contralateral side, diplopia)
- _*Proptosis_ - look from the sides to check for protruding eyeballs, look from the top of the eyes to check for lid retraction
- Graves’ disease (thyrotoxicosis), retro-orbital tumour
- Around bed - mobility aids, glasses, eye drops
What are the examples of mydriatic eye drops and miotic eye drops?
Mydriatic eye drops
- Anticholinergic drugs –> atropine, cyclopentolate, tropicamide
Miotic eye drops
- Cholinergic drugs –> pilocarpine
a) . What is Holmes-Adie pupil?
b) . Cause?
c) . Presentations?
d) . Ix?
e) . Mx?
a) . Holmes-Adie pupil is a unilateral dilated pupil caused by damage to the postganglionic parasympathetic nerve fibres that supply the sphincter papillae muscle in the iris - see image
b) . Caused by a viral infection
c) . Presentations
- Unilateral dilated pupil that reacts poorly to direct or consensual light reflex and to accommodation –> blurry vision
- Slowly reactive to accommodation but very poorly (if at all) to light
- The sphincter muscle can contract a little under prolonged stimulation with light, this causes the pupil to slowly constrict to light and slowly dilate in the dark
- The pupil remains small for an abnormally long time once it’s constricted
- The other pupil is of normal size and reacts to light
- Absent ankle/ knee reflexes
- Slip lamp shows sectoral iris atrophy and worm-like contractions
d) . Clinical diagnosis
e) . Mx - Pilocarpine 0.1%
* A Holmes-Adie pupil will constrict in response to pilocarpine due to denervation hypersensitivity but a normal pupil wouldn’t
Visual acuity:
When examining visual acuity, there are 3 parts to it: testing distance vision, near vision and colour vision.
How do you test a patient’s distance vision?
Test distant vision
- Assess using a *6m Snellen chart
- If the patient normally uses distance glasses, ensure these are worn for the assessment.
- Ask the patient to stand at 6 m away from the Snellen chart
- Ask the patient to cover one eye with their palm and read the lowest line on the Snellen chart they are able to
- “Are those the glasses that you normally use to look in the distance with?”
- “Can you keep those on for me please and cover up your left eye?”
- “Then with your right eye, read down as far the charts as you can”
- Get the patient to read through a pinhole to see if vision improves
- If it impoves –> refractive error (myopia)
- If it doesn’t –> amblyopia (‘lazy eyes’) or other non-refractive causes that likely affect the back of the eyes (vitreous or retina)
- “Fantastic! Now can I get you look through the little holes of this device and see how far down you can read?”
- Repeat the above steps with the other eye
- Recording visual acuity
- Visual acuity is recorded as chart distance (numerator) over the number of the lowest line read (denominator)
- Example (see image):
- If the patient can read til the 5th lowest line, their visual acuity is 6/18. This means that what the patient can read at 6 m, a normal person with a healthy eyesight can read the same text standing at 18 m away from the chart
- If the patient reads the 6/6 line but gets 2 letters wrong, record it as 6/6 (-2)
- If the patient gets more than 2 letters wrong, then the previous line should be recorded as their acuity
- Remember to state whether this vision was unaided (UA), with glasses or with pinholes (PH)
- If the patient is unable to read the top line of the 6m Snellen chart (even with pinhole):
- Use a 3m Snellen chart –> if still can’t read the top line –> use a 1m Snellen chart –> if still can’t read –> assess if they can count the number of fingers you are holding up (recorded as “Counting Finger” or “CF) –> if cannot read –> assess if they can see gross hand movements (recorded as “Hand Movements” or “HM”) –> if cannot see –> assess if they can detect light from a pen torch shone into each eye (recorded as “Perception of Light”/ “PL” or “No Perception of Light”/ “NPL”)
Visual acuity 2:
How do you examine near vision?
Test near vision
- Assess using a fine-print reading chart (can be just any letter or magazine)
- If the patient normally uses reading glasses, ensure these are worn for the assessment
- Ask the patient to cover one eye and read a paragraph of a small print in a book or newspaper
- Repeat on the other eye
Visual acuity 3:
How do you test for color vision?
Test colour vision
- If the patient normally wears glasses for reading, ensure these are worn for the assessment
- Ask the patient to cover one eye and read the numbers or describe the shape on the ishihara plates
- Note that the first page is a ‘test plate’, it does not test colour vision and instead assesses contrast sensitivity. If the patient is unable to read the test plate, document this
- If the patient is able to read the test plate, move through all of the ishihara plates and ask the patient to identify the number on each
- Document the number of plates the patient identified correctly, including the test plate e.g. 13/13
Which form of colour blindness is most common?
Red-green color blindness is the most common, followed by blue-yellow color blindness
What are the differential diagnoses for decreased visual acuity?
(Hints - think about the anatomy from anterior to posterior: cornea, lens, vitreous humor, retina, optic nerve…)
- Refractive errors
- Amblyopia (‘lazy eyes’) - usually in children
- Ocular medial opacities (refers to the transparent substances of the eye i.e. the cornea, the aqueous humor, the lens and the vitreous humor) - cataract, corneal scarring/ ulcer, vitreous haemorrhage
- Causes of cataract include:
- Old age
- Steroids (particularly eye drops with steroids in them)
- Smoking and alcohol
- Galactossaemia
- Blunt trauma
- Radiation e.g. X-rays
- Genetics - Down syndrome, Patau’s syndrome, Edward’s syndrome, Turner’s syndrome
- Skin problems e.g. eczema
- Post-vitrectomy (surgery to remove some/ all of the vitreous humor)
- Causes of cataract include:
- Retinal diseases e.g. age-related macular degeneration (AMD)
- Optic nerve pathology e.g. optic neuritis (seen in multiple sclerosis)
- Papilloedema does not usually affect visual acuity until it’s at a late stage!
- Lesions higher in the visual pathway
Visual fields:
When testing visual fields, there are 4 parts to it: test visual inattention, test visual fields, and test blind spots
How would you test for these 3 components?
Visual fields:
Sit the patient 1 m directly in front of you with both your eyes at the same level (confrontation technique). Get the patient to take off their glasses if they are wearing one
- Test visual inattention
- While the patient keeps both eyes open and focussed on you, hold out your hands in each of their outer visual fields and ask them to point at the hand(s) which you are opening or closing
- Inattention to one side (“hemineglect” or “spatial neglect”) –> contralateral parietal lesion (the dominant hemisphere is usually affected i.e. in most people the left side)
- Test visual fields
- Ask the patient to cover one eye with their palm e.g. the patient’s left eye, while you cover your right eye with your right palm
- Ask the patient to focus on your open eye
- Use a white visual field pin (if the background is NOT white) and bring it in from the periphery, keeping the pin at mid-distance between you and the patient. Ask them to tell you when they can see it and when they disappear
- _**“Have a look in my eye, and say ‘yes’ if you can see it and say ‘no’ if they disappear”_
- Move in a diagonal direction in each of the four quadrants
- Compare their visual fields with yours
- Repeat the above on the other eye
- Test blind spots
- Ask the patient to cover one eye with their hand
- If the patient covers their right eye with their right hand, you should cover your left eye with your left hand (mirroring the patient)
- Ask the patient to focus on your nose and keep their head still during the assessment
- Position the red hatpin at mid-distance between you and the patient at eye level, then move the pin horizontally towards the periphery in each direction and ask the patient to tell you when the pin disappears, while continusing to focus on your nose
- The blindspot is normally found just temporal (15o) to the central vision at eye level. The disppearance of the hatpin should occur at a similar point for you and the patient
- After the hatpin has disappeared for the patient, continue to move it laterally and ask the patient to let you know when they can see it again. The point at which the patient reports the hatpin re-appearing should be similar to the point at which it re-appears for you
- Map each of their blindspots against your own
- Large blindspots –> papilloedema
- Using the same technique, you can further assess the superior and inferior borders of the blindspot
What does enlarged blind spot indicate?
Papilloedema - caused by raised ICP e.g. brain tumour, hypertensive crisis, intracranial haemorrhage, cavernous sinus thrombosis
A patient comes to see you complaining of this type of visual field in one eye. See image.
What could be the causes of this visual field defect?
- Branch retinal vein or artery occlusion (esp the inferior branch)
- Inferior retinal detachment
- Ischaemic optic neuropathy
What are the different types of visual field defects? and What are their differential diagnoses?
Bitemporal hemianopia
- Loss of temporal visual field in both eyes causing central tunnel vision
- Caused by optic chiasm compression by a tumour e.g. pituitary adenoma or craniopharyngioma
Homonymous hemianopia
- Loss of the same side of the visual field in each eye (left nasal field + right temporal field OR right nasal field + left temporal field)
- Caused by stroke (MCA occlusion)
Homonymous inferior quadrantanopia
- Caused by lesion on superior optic radiations e.g. parietal tumour or MCA occlusion (superior branch)
Homonymous superior quadrantanopia
- Caused by lesion on inferior optic radiations e.g. temporal tumour or MCA occlusion (inferior branch)
Homonymous hemianopia with macular sparing
- Caused by PCA occlusion
Monocular vision loss
- Due to optic nerve or retinal pathology
- Optic nerve neuritis, optic atrophy, optic nerve glioma, optic sheath meningioma
- Retinal detachment, central retinal artery/ vein occlusion, glaucoma
Scotoma
- An area of absent or reduced vision surrounded by areas of normal vision
- It can affect any part of the visual system e.g. the retina (including the macula), the optic nerve and even the visual cortex
- If it affects the macula –> your central vision is affected
- Caused by many things including:
- Glaucoma
- Demyelinating disease e.g. MS
- Diabetic maculopathy
- Damage to nerve fibre layer in the retina (seen as cotton wool spots) due to HTN
- Pre-eclampsia in pregnant women
- Malignant HTN which causes an increase in ICP
- Vascular blockages either in the retina or optic nerve
- Stroke
- Age-related macular degeneration
- Scintillating scotoma in migraine with aura
- Pituitary tumour (causes scotoma that is reversible or curable by surgery)
Altitudinal visual field defect
- A condition in which there is a defect in the superior or inferior portion of the visual field that respects the horizontal midline. It can be unilateral or bilateral
- Caused by anything that damages the retinal nerve fibre layer
- Glaucoma (most common cause)
-
Branch retinal vein or artery occlusion
- Remember that occlusion of the inferior branch causes superior altitudinal visual field defect while occlusion of the superior branch causes inferior altitudinal visual field defect
- Retinal detachment
-
Anterior ischaemic optic neuropathy (AION)
- Arteritic (inflammation of arteries) - due to vasculitis e.g. GCA
- Non-arteritic - due to microvascular disease e.g. diabetes, HTN
- Optic disc drusen
- Papilloedema
Patients comes to the ophthalmology clinic to see you describing this kind of vision (see image)
What is this abnormal finding in this patient’s visual field? What condition is this defect usually associated with?
Scintillating scotoma - seen in migraine with aura
Note that every human being has a scotoma in its field of vision, and that scotoma is the blind spot. It has no photoreceptor cells. They are simply regions of reduced information within the visual field
However, a pathological scotoma may involve any part of the visual field and maybe of any shape or size. It may inclued and enlarge the normal blind spot. Scotoma affecting the central vision is the most debilitating as it can cause severe visual disability, whereas a large scotoma in the periphery of the visual field may go unnoticed
Describe the direct and indirect pupillary reflex pathways
(This is very important to know as it helps with understanding pathologies that cause unequal constriction/ dilatation of the pupils)
Each afferent limb of the pupillary reflex has two efferent limbs, one ipsilateral and one contralateral
Light hits the retina –> stimulates the photoreceptors in the retina –> generates an action potential (sensory input) –> optic nerve –> optic chiasm –> optic tract –> the neurone in the optic tract branches into two, one going to the LGN and the visual cortex while the other going to the ipsilateral pretectal area in the midbrain
The action potential generated from the pupillary light reflex travels to the ipsilateral pretectal area which gives rise to two interneurones supplying the Edinger-Westphal nuclei bilaterally (ipsilateral and contralateral)
Each Edinger-Westphal nucleus gives rise to efferent parasympathetic nerve fibres which travel in the oculomotor nerve to innervate the sphincter papillae, causing direct and consensual pupillary constriction
*The direct pupillary reflex assesses the ipsilateral afferent limb and the ipsilateral efferent limb of the pathway
The consensual pupillary reflex assesses the contralateral efferent limb of the pathway
The swinging light test detects RAPDs
Relative Afferent Papillary Defect (RAPD):
a) . What is a positive swinging light test?
b) . Why do you test for RAPD?
b) . What is the underlying pathophysiology (or mechanism) of RAPD?
a) . RAPD is a medical sign observed during the swinging-light test, whereupon the patient’s pupils dilate when a bright light is swung from the unaffected eye to the affected eye. It’s caused by a *partial defect in the afferent pathway (not complete defect) of the affected eye
b) . Testing for RAPD demonstrates if there is a difference in the amount of light that each optic nerve conducts to the midbrain. In other words, it assesses the health of one optic nerve relative to another and it does so by comparing how both pupils react to the swinging light test
c) . When the test is performed in an eye with an afferent pupillary defect, light directed in the affected eye will cause only mild constriction of both pupils (due to decreased response to light from the afferent defect), while light in the unaffected eye will cause a normal constriction of both pupils (due to an intact efferent path, and an intact consensual pupillary reflex). Thus, light shone in the affected eye will produce less pupillary constriction that light shone in the unaffected eye
If there is a complete defect in the afferent pathway e.g. a total CN2 lesion, in which the affected eye perceives no light, shining the light into the affected eye will produce zero dilation nor constriction
Is RAPD associated with a reduced visual acuity?
Yes, except in tectal RAPD where you get a normal visual acuity, a normal visual field, a normal fundoscopy examination and a normal OCT
See image
What if a patient has one normal eye and an abnormal eye with both afferent and efferent defects, how would you want to detect RAPH in the abnormal eye?
See image
a) . What are the causes of unilateral efferent defect?
b) . If a patient’s right eye has efferent defect, how does the right pupil and the left pupil react to light?
a). Causes of unilateral efferent defect
-
CN3 palsy
- The ipsilateral pupil is dilated and non-responsive to light entering either eye (due to loss of sphincter papillae function)
- The consensual light reflex in the unaffected eye would still be present as the afferent pathway (i.e. the optic nerve) of the affected eye and the efferent pathway (i.e. oculomotor nerve) of the unaffected eye remain intact
b). See image
What are the 3 changes that happen to your eyes during the accommodation reflex as you look at objects at a close distance?
Convergence of the eyes
Pupil constriction
Lens becomes more convex i.e. thickened to increase refractive power so light can falls on the retina
How do the action of the ciliary muscles and the suspensory ligaments change in relation to the lens size during distant and close-up vision?
Distant vision:
- Ciliary muscles relaxed
- Suspensory ligaments become taut
- Lens becomes thin as there isn’t a need for an increase in refractive power in distant vision
Close-up vision:
- Ciliary muscles contracted
- Suspensory ligaments become slack
- Lens becomes thickened (more convex) to increase the refractory power in close-up vision
Describe the pathway for the accommodation reflex?
Light hits the retina –> action potential generates in the optic nerve –> travels to optic chiasm –> optic tract –> LGN –> superior and inferior optic radiations –> visual cortex –> ipsilateral pretectal area –> ipsilateral EW nucleus + ipsilateral motor nucleus of CN3
EW nucleus –> parasympathetic nerve –> ciliary ganglion –> sphincter papillae + ciliary muscles –> pupillary constriction (this part is the same as the pupillary light reflex) + ciliary muscle contraction (–> lens thickened)
Ipsilateral motor nucleus of CN3 –> oculomotor nerve –> medial rectus –> eye convergence
Assessing strabismus:
What tests would you do to assess for strabismus of the eyes?
How would you perform these tests?
Corneal light reflex test (also called “Hirschberg test”)
- Ask the patient to focus on a target about half a meter away while you shine a pen torch towards both eyes
- Inspect the corneal reflex on each eye - see image
- If the eye alignment is normal, the light reflex will be positioned centrally and symmetrically in each pupil
- Deflection of the corneal light reflex in one eye suggests a misalignment
Cover test
- Ask the patient to fixate on a target e.g. a light switch
- Cover one of the patient’s eyes with an occluder and observe the other eye for a shift in fixation
- If there is no shift in fixation in the contralateral eye, while covering either eye –> normal alignment (orthotropic)
- If there is a shift in fixation in the contralateral eye, while covering the other eye –> misalignment (strabismus/ heterotropia)
- Repeat the cover test on the other eye
Cover test
See image
Testing eye movements:
How do you assess eye movements?
- Ask if the patient has any double vision and to tell you if they experience any during the test.
- Hold your finger (or a pin) about 30 cm in front of the patient’s eyes and ask them to focus on it. Look at the eyes in the primary position for any deviation or abnormal movements
- Ask the patient to keep their head still and follow your finger with their eyes, then move the finger in a ‘H’ pattern
- Observe for any restriction of eye movement and note any nystagmus
- Spontaneous unidirectional horizontal nystagmus towards the unaffected side (regardless of the direction the patient gazes at, the eye beats only in one direction –> vestibular nerve pathology (peripheral cause)
- Bidirectional nystagmus - fast phase to the left when looking to the left, then fast phase to the right when looking to the right –> stroke/ TIA (central cause)
See image as to how to test each extraocular muscle! (very important)
Fundoscopy:
a) . What must you do before you do fundoscopy?
b) . What do you check on fundoscopy?
a) . Ask patient to remove glasses if present, dim the lights in a room and consider preparing pupils with mydriatic drops (e.g. tropicamide)
b) . Test for the red reflex
- Adjust the diopter dial to correct your refractive error so that you can see the patient and their eye clearly from a distance
- Place your hand on the patient’s shoulder and shine the light towards the patient’s eye at a distance of one arm’s length at eye level
- The presence of a red/ orange reflection in each pupil is normal, caused by lgiht reflecting back from the vascularised retina
- Absence of red reflex in adults –> cataracts, vitreous haemorrhage, retinal detachment
- Absence of red reflex in children –> congenital cataracts, retinal detachment, vitreous haemorrhage, retinoblastoma
- The presence of white reflex (leukocoria) regardless of whether the red reflex is present –> any one of the pathologies mentioned above
Assess the anterior segment of the eye
- Adjust the diopter dial to a high green number (10 or 15)
- Stand to the side of the patient, place your left hand on the patient’s forehead (prevents accidental collision) and hold the ophthalmoscope in your right hand to examine their right eye with your right eye. When holding the ophthalmoscope, the index finger should be on the focus wheel and the forearm should be supine when holding it with the elbow pointing away from the patient
- Approach the eye as close as possible (if you think it’s close enough it’s probably not!) to assess the anterior segment
- Fluorescein dye can be applied to the eye which will stain yellow under the blue cobalt light filter of the ophthalmoscope if there is damage to the corneal or conjunctival epithelium (e.g. an abrasion)
- Look for white opacities on the cornea for corneal ulcer
Assess the fundus
- Adjust the diopter dial so that it is the net result of yours and the patient’s refractive error
- If you have a refractive error but you are wearing contact lenses / glasses to correct this, your refractive error is 0. Then you add your refractive error to the patient’s refractive error (for example patient has shortsightedness -2), it will give 0 + -2 = -2
- If things appear out of focus during the assessment, simply adjust the diopter dial until things look sharper!
- Assess the optic disc
- Begin by identifying a bv and then follow the branching of this bv towards the optic disc
- Check the 3Cs
-
Contours
- Swelling = papilloedema
-
Colour
- Grey/ pale = optic atrophy
-
Cup
-
Normal cup to disc ratio is 0.3 or less, i.e. the cup occupies 3/10 of the diameter of the entire disc)
- Enlarged cup to disc ratio = glaucoma
-
Normal cup to disc ratio is 0.3 or less, i.e. the cup occupies 3/10 of the diameter of the entire disc)
-
Contours
Fundoscopy 2:
Assess all four quadrants of the retina and the associated vascular arcades in a clockwise/ anticlockwise fashion
a) . What are the 4 quadrants?
b) . What pathological signs are you looking for in the retina?
a) . Follow the bvs out from the optic disc in each direction to visualise each of the 4 quadrants (superior temporal (ST), superior nasal (SN), inferior nasal (IN), inferior temporal (IT)) - see image
b) . Pathological signs of the retina:
* Generalised arteriolar narrowing with copper or silver wire appearance –> Early stages of hypertensive retinopathy
* Arteriovenous nipping/ nicking (the typical appearance involves bulging of retinal veins on either side of the area where the retinal artery is crossing) –> Grade 2 hypertensive retinopathy
* Dot and blot haemorrhages –> Diabetic retinopathy
* Flame haemorrhages (due to rupture of pre-capillary arterioles or small veins in the retinal nerve fibre layer) –> Central retinal vein occlusion, grade 3 hypertensive retinopathy, thrombocytopenia, trauma
* Cotton wool spots (appears as small, fluffy, white superficial lesions, they represent infarcts of the neuroretinal layer) –> Diabetic retinopathy, grade 3 hypertensive retinopathy
* Hard exudates (waxy yellow lesions arranged in clumps or rings, often surrounding leaking microaneurysms) –> Diabetic retinopathy, grade 3 hypertensive retinopathy
* Neovasculation (formation of new bvs that appear as a net of small curly vessels +/- associated haemorrhages) –> Advanced proliferative diabetic retinopathy
* Pan-retinal photocoagulation (primary treatment for proliferative diabetic retinopathy) –> clusters of pale burn marks on the retina caused by the laser
* Branch retinal vein occlusion (BRVO) (this occurs when one of the four retinal veins is blocked) –> flame haemorrhages, hard exudates, cotton wool spots, dot and blot haemorrhages, retinal oedema, dilated tortuous veins
* Peripheral pigmentation –> retinitis pigmentosa
Fundoscopy 3:
a) . How do you assess the macula?
b) . What signs of the retina are suggestive of macula pathology?
a) . Ask the patient to look directly into the light of the ophthalmoscope. The macula is found lateral to the optic nerve head and is yellow in colour. The central part of the macula, the “fovea” appears darker than the rest of the macula due to the presence of an additional pigment
b) . Pathological signs of the retina suggestive of macula pathology
* Hard exudates –> Diabetic retinopathy, grade 3 hypertensive retinopathy, retinal vein occlusion
* Drusen (hard/soft) (see image) (yellow-white flecks scattered around the macular region representing remnants of dead retinal pigment epithelium) –> Age-related macular degeneration
* Cherry-red spot –> Central retinal artery occlusion (the cherry red spot is caused by the ischaemic pale retina in CRAO which exposes the underlying vascular (red) choroid)
What does this fundoscopy show?
Peripheral pigmentation –> Retinitis pigmentosa
A patient comes to see you with this visual field defect in his right eye. What is this visual field defect called? What conditions may it suggest?
Superior altitudinal field defect, seen in glaucoma, inferior branch retinal vein or artery occlusion, inferior retinal detachment, AION
