The red eye

Question 1

What are the steps to follow when thinking a case of red eye through?

Answer 1

1. what where and how redness occurs in this particular case
2. investigations that may be needed
3. tx plan

Question 2

Where are the different possible rednesses in the eye?

Answer 2

redness of ocular adnexa and cornea/sclera
iris hyperaemia
intraocular bleed

Question 3

How can the area of the eye become red?

Answer 3

consider whole globe and adnexa
outside to inside
what structures are in the tissue i’m thinking of?
how would the tissues respond to insult?
how would changes in one tissue affect other tissues around it?
can this be a normal variation for this patient?
can any structures i can’t see be involved?
ocular vs systemic

Question 4

Where, what and how can eyelids be red?

Answer 4

where: red periocular tissue
what: skin, muscles, meibomian galnds, conjunctiva
how: hyperamia, swelling, ulcers, crusts, loss of hair, etc.

Question 5

What are common causes of red eyelids?

Answer 5

periocular dermatitis (many causes, some systemic and potentially severe)

meibomian glands (can become infected, inflamed, neoplastic)

Question 6

How can abnormal eyelids affect the cornea and the tear film?

Answer 6

loss of protective effect
loss of oily component of tears
abnormal contact: hair or masses contacting the ocular surface

Question 7

What can abnormal eyelids lead to?

Answer 7

irritation of the white eye: conjunctival hyperaemia
corneal irritation: corneal neovascularisation and ulceration

Question 8

Where and what can the third eyelid be red?

Answer 8

where: red ocular coats
what: cartilage, lymphoid tissue, accessory lacrimal gland

Question 9

How can the third eyelid become red?

Answer 9

T shape cartilage holds up the third eyelid against the eye: can curl and cause and outward fold
large amount of lymphoid tissue (prominent in some cases) on the inner side and accompanied with hyperaemia
accessory lacrimal gland which produced 30% of aqueous component of tears can prolapse and become inflamed

Question 10

What is the normal TEL?

Answer 10

some vasculature visible but minimal
variable pigmentation

Question 11

What are potential causes for TEL hyperaemia and swelling?

Answer 11

ocular surface disease
orbital disease
TEL neoplasia

Question 12

What is TEL follicular proliferation?

Answer 12

presence of multiple small “bubbles” on the external and internal TEL
seen in young animals, allergies, certain infections in cats
mainly present on inner side
usually accompanied with hyperaemia

Question 13

Where what and how can the conjunctiva be red?

Answer 13

where: red ocular coats
what: mucous membrane lining eyelids, third eyelid, sclera, epithelium, goblet cells, lymphoid tissue, blood vessels
how: hyperaemia, swelling, ulcers, lymphoid follicles

Question 14

What is conjunctival hyperaemia a sign for?

Answer 14

ocular surface disease

Question 15

Where what and how can the episclera/sclera become red?

Answer 15

where: red ocular coats
what: fibrous tunic of the globe, collagen, blood vessels
how: hyperaemia and swelling

Question 16

What is episcleral hyperaemia a sign of?

Answer 16

sign of deeper ocular tissues diseases (including intraocular)

Question 17

What does the normal conjunctiva/sclera/episclera look like?

Answer 17

conjunctival vasculature is present but minimal
episcleral vasculature is rarely seen in normal conditions

Question 18

What is the difference between conjunctival and episcleral hyperaemia?

Answer 18

conjunctival: sign of ocular surface disease, dichotomous division, superficial vessels that move with the conjunctiva, most evident in the fornixes

episcleral: sign of deeper ocular tissues disease, no division and dont move with the conjunctiva, most evident close to the limbus

Question 19

How can you tell if there is conjunctival or episclera hyperaemia?

Answer 19

conjunctival: tortuous, branching, bright red, vessels move with conjunctiva, most evident at fornixes

episcleral: straight and deep red, vessels stationary, most evident closer to limbus

Question 20

Where what and how can the cornea become red?

Answer 20

where: red ocular coat
what: anterior part of fibrotic tunic of the globe
how: corneal neovascularisation, +/- intracorneal bleed

Question 21

What is superficial corneal neovascularisation a sign of and what does it look like?

Answer 21

sign of oculaar surface disease
dichotomous division, long and branching (like trees)
may occur with or without corneal ulceration

Question 22

What is the difference between superficial and deep corneal neovascularisation?

Answer 22

superficial: sign of ocular surface disease, dichotomous division, long branching vessels

deep: sign of deeper ocular disease, short straight deep red vessels, usually stay close to the limbus and look like a bush

Question 23

What is ulcerative keratitis and how is it diagnosed?

Answer 23

infection causing
- conjunctival hyperaemia
- superficial corneal neovascularisation

positive fluorescein stain
STT1 variable

Question 24

What is keratoconjunctivitis sicca and how is it diagnosed?

Answer 24

dry eye causing
- conjunctival hyperaemia and ocular discharge
- superficial corneal neovascularisation

fluorescein stain variable
STT1 low

Question 25

What is deep corneal neovascularisation a sign of?

Answer 25

sign of deep ocular tissues disease (including intraocular)

Question 26

What are 2 causes for deep corneal neovascularisation?

Answer 26

uveitis
glaucoma

Question 27

What are the signs of uveitis?

Answer 27

episcleral hyperaemia
deep corneal neovascularisation
small pupil (miosis)
low intraocular pressure

Question 28

What are the signs of glaucoma?

Answer 28

episcleral hyperaemia
deep corneal neovascularisation
dilated pupil (mydriasis)
high intraocular pressure

Question 29

What is intracorneal haemorrhage sign for?

Answer 29

relatively uncommon

always associated to corneal neovascularisations
can be associated to systemic disease (systemic hypertension)

Question 30

Where and what in the aterior chamber or the vitreal cavity can be red?

Answer 30

where: intraocular bleed
what: in normal conditions there is aqueous humour but at the limits of the chamber there is the cornea, iris and iridocorneal angle

Question 31

What are 4 possible abnormalities that could be found in the anterior chamber?

Answer 31

hyphema: blood
hypopion: WBC
aqueous flare: proteins
fibrinous uveitis: fibrin

Question 32

How can the anterior chamber or the vitreal cavity become red?

Answer 32

inflammation (uveitis)
trauma (penetrating or blunt)
intraocular neoplasia
retinal detatchement
glaucoma
congenital defect
systemic condition (hypertension, thrombopathy, coagulopathy

Question 33

Where what and how can the anterior uvea become red?

Answer 33

where: iris hyperaemia (iris rubeosis)
what: uveal vasculature, connective tissue, pigmentation
how: uveal bleed, tumour, engorgment of normal vessels, formation of new vasculature over iris surface

Question 34

What are pre-riridal fibrovascular membranes?

Answer 34

PIFM
formation of new vasculature over the iris surface
secondary to uveitis, intraocular tumour, retinal detatchement or glaucoma

Question 35

Where what and how can the posterior uvea/retina be red?

Answer 35

where: intraocular bleed
what: posterior uvea and retina (neuronal cells and retinal vacs.)
how: similar to anterior uvea, most common bleed from the retinal/choroidal vasculature

• some anatomical variations can mimic retinal/choroidal bleeds

Question 36

Where and what in the retrobulbar space can be red?

Answer 36

where: red 3rd eyelid and red ocular coats
what: intraconal space (extraocular musculature, nerves and vessels), extraconal space (lacrimal and salivary glands, bone, teeth roots and other nerves and vessels)

Question 37

How can the retrobulbar space be red?

Answer 37

any growing structure within the retrobulbar space (infl. infec. neopl.) will most likely deviate the globe as well as compromising the vascular return from the rest of orbital structures
some orbital conditions can be associated with orbital bleeds or can affect the globe causing an intraocular bleed

Question 38

What tests are important to not forget in cases presenting with red eye?

Answer 38

STT1
fluorescein stain
IPO/tonometry

• be aware of contraindications for these tests

Question 39

What cases of red eye contraindicate the use of STT1, fluorescein stain and tonometry tests?

Answer 39

corneal or scleral rupture
may present with red eye
patients should be minimally manipulated and treated as a fragile eye

Question 40

What diagnostic tests are important when suspecting infectious keratitis?

Answer 40

corneal cytology
culture and sensitivity

Question 41

What diagnostic tests are important when suspecting glaucoma?

Answer 41

gonioscopy (slit lamp used to evaluate the eye’s drainage angle)

Question 42

What diagnostic tests are important when suspecting uveitis?

Answer 42

systemic investigations
ocular ultrasound

Question 43

What diagnostic tests are important when suspecting retrobulbar disease?

Answer 43

MRI/CT

Question 44

What does a tx plan in gp look like?

Answer 44

give diagnosis and advise when possible
tx what you feel confident about
refer to a specialist when necessary

Question 45

When to refer or consult with an eye specialist?

Answer 45

when not confident in dx or tx plan
when not able to perform a complete ophtalmic exam
when there is risk of losing the eye or the sight
complex cases or cases requiring further investigation