Ophthalmoscopy

Question 1

What do you need for fundoscopy?

Answer 1

Ophthalmoscope

Mydriatic eye drops

Question 2

How would you structure fundoscopy?

Answer 2

1. Introduction
2. Inspection of the external eye
3. Preparation for fundoscopy
4. Assess the fundal reflex
5. Assess the fundus
6. Complete examination

Question 3

How would you explain fundoscopy?

Answer 3

“I will be using a magnifying tool called an ophthalmoscope to look at the back of your eyes with the lights off.”

“To do this, I’ll need to get quite close to your face. I’ll place a hand on your forehead to prevent us from bumping into each other.”

“I’ll also be using some eye drops to dilate your pupils. The dilating drops will cause your vision to be temporarily blurry and you’ll be more sensitive to light, so you’ll not be able to drive for several hours afterwards.”

Question 4

What are the parts of the general inspection of the eye?

Answer 4

1. General inspection (peri-orbital region, eyelids, eyes)

2. Pupillary assessment (size, shape, symmetry, colour)

Question 5

What would you focus on in the general inspection?

Answer 5

1. Swelling
2. Redness
3. Discharge
4. Prominence of the eyes
5. Abnormal eyelid position: ptosis can be a sign of Horner’s syndrome (often very subtle ptosis with miosis) and oculomotor nerve palsy (can vary from partial to complete ptosis and usually with a ‘down and out’ eye position and an enlarged pupil)
6. Abnormal pupillary shape, size and/or asymmetry

Question 6

What suggests pupil symmetry abnormality?

Answer 6

This may be longstanding and physiological or be due to acquired pathology. If the difference in pupil size becomes greater in bright light such as when facing a window in daylight, this would suggest that the larger pupil is the pathological one

Examples of asymmetry include a larger pupil in oculomotor nerve palsy and a smaller one in Horner’s syndrome.

Question 7

What can causes abnormality in pupil colour?

Answer 7

Asymmetry in pupillary colour is most commonly due to congenital disease.

In rare cases, asymmetry of colour can suggest Horner’s syndrome, with the paler washed-out iris being pathological.

Question 8

What abnormalities can you find in the general inspection?

Answer 8

1. Periorbital erythema and swelling: a feature of preseptal cellulitis (anterior to the orbital septum) or orbital cellulitis (posterior to the orbital septum)
2. Eyelids: lumps (benign or malignant), oedema, ptosis and entropion/ectropion
3. Eyelashes: loss of eyelashes (can be associated with malignant lesions), trichiasis (eye lashes rubbing on the cornea) and blepharitis collarettes
4. Pupils: abnormal size, shape, colour and symmetry (see above)
5. Conjunctival injection (redness): this can be diffuse, sectorial or limbal. Dilated inflamed blood vessels can be due to infection, allergy, trauma and inflammation.
6. Cornea: diffuse haziness in acute angle-closure glaucoma or a patch of white infiltrate due to a corneal ulcer. Staining of the cornea with fluorescein suggests epithelial loss. A dendritic pattern is seen with herpes simplex infection.
7. Anterior chamber: a fluid level may be noted in hyphaema (blood – red in colour) or a hypopyon (inflammatory cells – yellow in colour).
8. Discharge: watery discharge is typically associated with allergic or viral conjunctivitis or reactive physiological production (e.g. corneal abrasion/foreign body). Purulent discharge is more likely to be associated with bacterial conjunctivitis. Very sticky, stringy discharge can suggest chlamydial conjunctivitis while blood staining can be seen with gonococcus.

Question 9

What are causes of painless red eye?

Answer 9

1. Conjunctivitis
2. Subconjunctival haemorrhage
3. Episcleritis
4. Dry eyes

Question 10

What are causes of painful red eye?

Answer 10

1. Uveitis
2. Scleritis
3. Foreign body
4. Acute angle-closure glaucoma
5. Corneal abrasion
6. Corneal ulcer

Question 11

What would you use different sized apertures for?

Answer 11

Micro aperture: used for viewing the fundus through very small undilated pupils

Small aperture: used for viewing the fundus through an undilated pupil

Large aperture: used for viewing the fundus through a dilated pupil and for the general examination of the eye

Slit aperture: can be helpful in assessing contour abnormalities of the cornea, lens and retina as it makes elevation easier to see

Question 12

What would you use different colour lights for?

Answer 12

Cobalt blue filter: used to look for corneal abrasions or ulcers with fluorescein dye (see our anterior segment examination guide for more details)

Red-free filter: used to look at the centre of the macula and other vasculature in more detail

Question 13

How would you prepare for fundoscopy?

Answer 13

1. Darken the room after seating the patient
2. Dilate the patient’s pupils using short-acting mydriatic eye drops such as tropicamide 1%
3. Ask the patient to look straight ahead for the duration of the examination

Question 14

How does the red reflex differ based on skin colour?

Answer 14

In patient’s with lighter skin, the reflex typically appears orange-red in colour, whereas in those with darker skin, the reflex can be yellow-white or even blue in colour.

The term fundal reflex is preferred over red reflex as the colour of the healthy reflex varies depending on a patient’s skin colour.

Question 15

How would you assess the fundal reflex?

Answer 15

1. Look through the ophthalmoscope, shining the light towards the patient’s eye at a distance of approximately one arm’s length.
2. Observe for a reddish/orange/white/yellow/blue reflection in each pupil, caused by light reflecting back from the vascularised retina.

Question 16

What causes an absent fundal reflex in adults? And in children?

Answer 16

Absence of the fundal reflex in adults is often due to cataracts in the patient’s lens blocking the light. Other causes include vitreous haemorrhage and retinal detachment.

Absence of the fundal reflex in children can be due to congenital cataracts, retinal detachment, vitreous haemorrhage and retinoblastoma.

Question 17

How would you assess the fundus?

Answer 17

1. Make sure you adjust for own and patient’s refractory error!! (me: 0, patient -2 = -2)
2. Assess the optic disc
3. Assess the retina
4. Assess the macula

Question 18

What would you say about the optic disc?

Answer 18

1. Contour: the borders of the optic disc should be clear and well defined
2. Colour: a healthy optic disc should look like an orange-pink doughnut with a pale centre. The orange-pink colour represents well-perfused neuro-retinal tissue. A pale optic disc suggests the presence of optic atrophy which can occur as a result of optic neuritis, advanced glaucoma and ischaemic vascular events.
3. Cup: the cup is the pale centre of the orange-pink doughnut mentioned previously. The pale colour of the cup is due to the absence of neuroretinal tissue. The vertical size of the cup can be estimated in relation to the optic disc as a whole, known as the “cup-to-disc ratio”. A cup-to-disc ratio of 0.3 (i.e. the cup occupies one-third of the height of the optic disc) is generally considered normal. An increased cup-to-disc ratio suggests a reduced volume of healthy neuro-retinal tissue, which can occur in glaucoma.

Question 19

What would you say about the retina?

Answer 19

Methodically assess each quadrant of the retina and the associated vascular arcades in a clockwise or anticlockwise fashion looking for evidence of pathology:

1. Superior temporal (ST)
2. Superior nasal (SN)
3. Inferior nasal (IN)
4. Inferior temporal (IT)

Question 20

What are common retinal pathologies?

Answer 20

1. Arteriolar narrowing: subtle, with generalised arteriolar narrowing with typical copper or silver wire appearance. Most commonly associated with the early stages of hypertensive retinopathy.
2. Arteriovenous nipping/nicking: areas of focal narrowing, and compression of venules at sites of arteriovenous crossing. The typical appearance involves bulging of retinal veins on either side of the area where the retinal artery is crossing. Most commonly associated with grade 2 hypertensive retinopathy.
3. Dot and blot haemorrhages: arise from bleeding capillaries in the middle layers of the retina and may look like microaneurysms if small enough. They are most commonly associated with diabetic retinopathy.
4. Flame haemorrhages: larger haemorrhages with a flame-like appearance caused by rupture of pre-capillary arterioles or small veins in the retinal nerve fibre layer. Most commonly associated with grade 3 hypertensive retinopathy, thrombocytopaenia, retinal vein occlusion and trauma.
5. Cotton wool spots: appear as small, fluffy, whitish superficial lesions and represent infarcts of the neuro-retinal layer. They are most commonly associated with diabetic retinopathy and grade 3 hypertensive retinopathy.
6. Hard exudates: waxy yellow lesions with relatively distinct margins arranged in clumps or rings, often surrounding leaking microaneurysms. They are most commonly associated with diabetic retinopathy and grade 3 hypertensive retinopathy.
7. Neovascularisation: formation of new blood vessels that appear as a net of small curly vessels, with or without associated haemorrhages. They may be located on the optic disc or elsewhere on the retina. They are most commonly associated with advanced proliferative diabetic retinopathy.
8. Pan-retinal photocoagulation: the primary treatment for proliferative diabetic retinopathy. Clinically it is seen as clusters of pale burn marks on the retina which have been created by the laser used in the treatment process.
9. Branch retinal vein occlusion: blockage of one of the four retinal veins, each of which drains about a quarter of the retina. Typical signs include flame haemorrhages, dot and blot haemorrhages, cotton wool spots, hard exudates, retinal oedema, and dilated tortuous veins.

Question 21

How would you assess the macula?

Answer 21

Inspect the macula by asking the patient to briefly look directly into the light of the ophthalmoscope. The macula is found lateral (temporal) to the optic nerve head and is yellow in colour. The central part of the macula, the “fovea” is about the same diameter as the optic disc and appears darker than the rest of the macula due to the presence of an additional pigment.

Question 22

What are types of macula pathologies?

Answer 22

1. Hard exudates: waxy yellow lesions with relatively distinct margins arranged in clumps or rings, often surrounding leaking microaneurysms. They are most commonly associated with diabetic retinopathy, grade 3 hypertensive retinopathy and retinal vein occlusions.
2. Drusen: yellow-white flecks scattered around the macular region representing remnants of dead retinal pigment epithelium. Most commonly caused by age-related macular degeneration.
3. Cherry-red spot: associated with central retinal artery occlusion which typically presents with sudden profound visual loss.

Question 23

How would you conclude the examination?

Answer 23

Explain to the patient that the examination is now finished.

Thank the patient for their time.

If mydriatic drops were instilled, remind the patient they cannot drive for the next 3-4 hours until their vision has returned to normal.

Dispose of PPE appropriately and wash your hands.

Summarise your findings.

Question 24

What would you suggest after fundoscopy?

Answer 24

1. Amsler chart: to assess for central visual loss and distortion which is commonly associated with macular degeneration.
2. Cranial nerve examination: to further assess for evidence of cranial nerve pathology (e.g oculomotor nerve).
3. Blood pressure: if there are concerns about hypertensive retinopathy.
4. Capillary blood glucose: if there are concerns about diabetic retinopathy.
5. Retinal photography: to better visualise any abnormalities noted on fundoscopy.