conjunctiva Flashcards
what is the conjunctiva
translucent mucous membrane that covers the anterior globe and terminates at the corneoscleral limbus. The conjunctiva is continuous with the skin at the eyelid margin
parts of the conjuctiva
- Palpebral conjunctiva: Starts at the mucocutaneous transitional zone of the lid margin and is strongly adherent to the posterior aspect of the tarsal plates.
- Forniceal conjunctiva: A loose fold made by the conjunctiva, covering the posterior eyelid and anterior surface of the eyeball.
- Bulbar conjunctiva: The thinnest part, covering the anterior surface of the sclera. It is loosely attached, except at the limbus where it is fused with underlying sclera and Tenon’s capsule.
mainly nerve supply to conjunctiva
mainly CNV1
inferior conjunctiva - infraorbital nerve
limbus - long ciliary nerve, branch of the nasociliary nerve
blood supply to the conjunctiva
palpebral and forniceal - supplied by the peripheral and marginal arterial arcades
bulbar - posterior and anterior conjunctival arteries
lymphatic drainage of the conjunctiva
medial - submandibular lymph nodes
lateral part - preauricular lymph nodes.
pathogens for bacterial conjunctivitis
streptococcus pneumoniae
- Staphylococcus aureus, - Haemophilus influenzae
- rarely, Neisseria gonorrhoeae.
features
of bacterial conjunctivitis
ASS w
● Unilateral to bilateral.
● Redness, grittiness and purulent discharge.
● ‘sticky eye’ upon awakening.
● Hyperaemia (conjunctival injection).
● Gonococcal disease is typically more severe and hyperacute.
Associated with
lid oedema, severe mucopurulent discharge and lymphadenopathy. (Note: Lymphadenopathy is not present in typical bacterial conjunctivitis.)
Mx for conjunctivitis bacterial
self-limiting.
If severe, treat with topical chloramphenicol or fusidic acid.
chlamydial conjucntivits what is it
serological variants D–K of Chlamydia trachomatis.
It causes a subacute onset of unilateral conjunctivitis; if left untreated, it may follow a chronic course.
Ix of chlamydia conjunctivitis
● Giemsa stain: Basophilic intracytoplasmic inclusion bodies.
● Direct immunofluorescent staining: Free elementary bodies.
● Swab for culturing (McCoy).
features
signs
of chlamydia conjunctivitis
● Red eye with mucopurulent discharge.
● Preauricular lymphadenopathy.
● Follicles (whitish, round and discrete swellings) are present, most commonly in the inferior fornix.
● Epithelial keratitis and subepithelial corneal infiltrates may occur.
● Reiter syndrome: Urethritis + arthritis + conjunctivitis/anterior uveitis.
Mx for chlamydial conjunctivitis
1 g oral azithromycin single dose
OR
100 mg doxycycline twice a day for 14 days.
what is trachoma
leading cause of infectious blindness worldwide
serological variants A–C of C. trachomatis.
Carried by fly vector or direct eye/nasal discharge
type 4 hypersensitivity reaction
trasmission of trachoma
musca sorbens fly act as a vector
RFs of trachoma
- poverty and poor hygiene
pathophysiology of trachoma
A type IV hypersensitivity reaction. Trachomatous disease is split into two parts: an active inflammatory phase and a cicatricial (scarring) chronic phase.
active inflammation
scarring
trichiasis
blindness due to the corneal damage due to eyelashes irritating the cornea
nnocuous + heightened inflammatory response upon reinfection
epidemiology of trachoma
● The most trachoma-endemic continent is Africa.
● The highest prevalence is in Ethiopia.
● Number of global visually impaired or blind: 1.9 million people.
● Women are four times more likely to require surgery for trichiasis.
WHO staging of trachoma
- Trachomatous inflammation-follicular (TF): 5+ follicles present in the upper tarsal conjunctiva.
- Trachomatous inflammation-intense (TI): Upper tarsal conjunctiva is thickened, and the majority of the blood vessels are obscured.
- Trachomatous scarring (TS): Conjunctival scarring (cicatricial).
- Trachomatous trichiasis (TT): Ingrowth of eyelashes towards the cornea.
- Corneal opacity (CO): Due to eyelashes rubbing on the cornea.
what is the active inflammatory phase of trachoma
● Follicular conjunctivitis: Most prominent in the superior tarsal plate. May be associated with papillae (red, elevated dots with a vascularized centre).
● Vascularization of the superior cornea (pannus formation).
what is the chronic cicatricial phase
● Herbert pits: Shallow depressions in the superior limbus created by follicles (pathognomonic for trachoma).
● Arlt’s line: Conjunctival scars.
● Trichiasis, entropion and eventual corneal opacities may eventually develop.
Mx for trachoma
WHO ‘SAFE’ strategy (2):
● Surgery for trichiasis: Bilamellar tarsal rotation surgery can be performed to correct trichiasis.
● Antibiotics: Single dose of 1 g oral azithromycin.
● Facial cleanliness.
● Environmental improvement.
Tx: Azithromycin, Erythromycin, Doxycyline. WHO – “SAFE”
what is opthalmia neonatorium
Ophthalmia neonatorum is defined as conjunctival inflammation developing in the first 30 days of life
causes of opthalmia neonatrum
chlamydia
gonococcal
HSV
Staphylococci
features
onset
Mx of chlamydia conjunctivitis
Mucopurulent discharge and papillary conjunctivitis
1-3 weeks
oral erythromycin
features
onset
Mx of gonococcal opthalmia neonatrum
Hyperpurulent discharge, eyelid swelling ± corneal ulcer
1-3 days
IM ceftriaxone
features
onset
Mx of HSV
Watery discharge, periocular skin vesicles and dendritic corneal epithelial lesion
1-2 weeks
IV acyclovir
features
onset
Mx of staphylococci
purulent discharge and mild sticky eye
1 week
topical chloramphenicol
most common causativr agent in viral conjunctivitis
adenovirus
Herpes simplex
Molluscum contagiosum
features of acute nonspecific follicular conjunctivitis
type of viral conjunctivitis
- red, itchy, gritty eye w ass watery discharge
- starts unilateral but progresses to bilateral involvement after a couple of days
- follicular conjunctivitis withi conjunctival hyperaemia
- periauricular lymphadenopathy
features of pharyngoconjunctival fever
due to adenoviral serotypes 3,4 and 7
- fever
- pharyngitis
- conjunctivitis
- lymphadenopathy
- keratitis
epidemic keratoconjunctivitis
which type of virus
signs seen
due to adenoviral serotypes 8, 19 and 37
- conjunctivitis
- keratitis:
- – occurs after conjunctivitis
- – characterised by epithelial microcysts (early) and punctate epithelial keratitis (late)
- – more common in EKC than in PCF
subtypes of allergic conjunctivitis
- Seasonal and perennial allergic conjunctivitis
- Vernal keratoconjunctivitis (VKC)
- Atopic keratoconjunctivitis (AKC)
- Giant papillary conjunctivitis
types of seasonal and perennial allergic conjunctivitis
- Seasonal: IgE-mediated type I hypersensitivity. Worse during spring and summer.
- Perennial: IgE-mediated type I hypersensitivity. All year round when exposed to allergens.
features of seasonal and perennial allergic conjunctivitis
● Red, watery and itchy eye.
● May be associated with rhinitis.
● Conjunctival hyperaemia and papillary conjunctivitis.
Mx of seasonal and perrineal allergic conjunctivitis
● Avoid allergens
● Artificial tears
● Topical/oral antihistamines
● Topical sodium cromoglicate
what is Vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC)
Both VKC and AKC affect conjunctiva, eyelids and the cornea
They are both bilateral conditions, expressing IgE-mediated (type I hypersensitivity) and T-cell-mediated (type IV hypersensitivity) immune responses.
symptoms of VKC and AKC
itching, discharge, blepharospasm and photophobia.
Mx of VKC and AKC
● Avoid allergens ● Artificial tears ● Topical/oral antihistamines ● Topical cromoglicate ● Topical ciclosporin ● Topical steroids
wjat is giant papillary conjunctivitis
A type I and IV hypersensitivity reaction to contact lens wear. Patients usually complain of increased ocular tiredness while wearing contact lenses.
- ass w pruritus
- red eye
mucous secretion
worse after taking off the lenses
signs of giant papillary conjunctivitis
● Superior tarsal hyperaemia.
● Superior tarsal papillae (classically ‘giant’ >1 mm; however, size is not
necessary for diagnosis).
what is ocualr mucous membrane pemphigoid
patho
common in who
This is a chronic, blistering autoimmune disease. It has a type II hypersensitivity response to autoantibodies attacking the basement membrane. Typically, elderly females are affected.
features of ocular mucous membrane pemphigoid
● Bilateral conjunctivitis with conjunctival hyperaemia, swelling and subepithelial fibrosis (mostly seen in inferior fornix), associated with reduced inferior forniceal depth.
● Symblepharon: Union of the palpebral and bulbar conjunctiva.
● Dry eyes due to goblet cell destruction.
● Trichiasis.
● Chronic blepharitis.
● Ankyloblepharon: Union of lateral canthus and both eyelids.
● Keratinization, vascularization and epithelial defects of the cornea may
ensue.
Ix of ocular mucous membrane pemphigoid
Direct conjunctival immunofluorescence: linear bands of IgG and IgA deposits at the basement membrane.
Mx for ocular mucous membrane pemphigoid
Dapsone can be used for mild disease. Other immunomodulatory agents (e.g. azathioprine and methotrexate) can be used for more severe cases. Corticosteroids are useful for severe acute cases.
define Superior limbic keratoconjunctivitis (SLK)
idiopathic chronic inflammatory condition affecting the superior bulbar conjunctiva, limbus and cornea.
SLK ass with
females and there appears to be a strong association with TED. There is also an association with sicca syndrome and rheumatoid arthritis.
features of SLK
Gradual-onset foreign body, burning and itching with associated photophobia and pain. On examination, there is:
● Localized conjunctival hyperaemia and papillary reaction superiorly.
● Occasionally, thickening of the superior bulbar conjunctiva is seen. This
stains with fluorescein and rose bengal stains.
● Cornea may be affected with superior punctate epithelial erosions and
filamentary keratitis.
What is parinaud oculoglandular syndrome
various bacterial, fungal and viral agents, most notably Bartonella henselae (cat scratch disease).
- granulomatous unilateral conjunctivitis - with ipsilateral preauricular lymphadenopathy associated with a
- low-grade fever.
what is pinguecula
Bulbar conjunctival degeneration characterized
- yellow/white patch most commonly on the nasal limbus.
It never grows over the cornea. Risk factors include ultraviolet light exposure and ageing.
what is pterygium
Bulbar conjunctival degeneration characterized by a pink fleshy triangular- shaped fibrovascular wedge (Figure 9.1). Usually arises on the nasal limbus, causing destruction of Bowman’s layer, and grows over the cornea.
complications of pterygium
obscuring the optical access and causing astigmatism. Risk factors are ultraviolet light and dry climates.
features of pterygium
● Stocker’s line: Epithelial iron deposits in the cornea.
● Fuchs’ islets: Small white dots in the cornea.
● May cause ocular dryness, astigmatism or reduced vision (if within visual axis).
Mx of pterygium
Conservative management (reassurance, lubrication) or surgical excision for cosmesis or for visual interference. However, it should be noted that recurrence is high.
Sx of endophthalmitis
redness pain bliurred vision floaters photosensitivity hypopyon corneal haze
RFs of vernal conjunctivitis
Atopic; African / Asian descent
- Affects superior palpebral conjunctiva
- Giant papillae
- Horner-trantas dots
vernal v atopic keratoconjunctiivtis
look at lecture
causes of pseudopterygium and its difference
Acute inflammatory episode:
- Chemical burn
- Corneal ulcer - Trauma
- Cicatrizing conjunctivitis
only attached at apex
causes of pingecula to pterygium
Chronic UV exposure Chronic surface dryness Hot climates
