The anterior eye Flashcards
what are the tear film layers in order from outer to inner
- lipid layer
- aqueous layer
- aqueous phase (MUC 5AC)
- glycolax (MUC1), (MUC 4), (MUC 16)
- mucinous phase
- epithelial surface with microvilli
what can ocular surface and tear film disorders cause?
DED
MGD
CL DISCOMFORT
what are two types of dry eye disease? what are there symptoms?
dry eye syndrome (DES) and keratoconjunctivitis sicca (KCS)
-dryness
-discomfort
-irritation
-reduced vision
what are the two types of dry eye?
-aqueous deficiency where is affects the lacrimal gland function
-evaporative dry eye
what is the most frequent cause of DED?
MGD
why is it important to prevent DED
-it is very expensive to treat i.e.. cost of referrals, Px etc
what are the 4 inter-related mechanisms responsible for DED
-tear instability
-tear hyperosmolarity
-inflammation
-ocular surface damage
what is evaporative dry eye?
related to causes from
-lids such as MDG and blink problems
-ocular surface such as mucin or CL-related
what is another name for MGD
posterior blepharitis
how is obstructive MGD caused?
- terminal duct obstruction
- caused by hyperkeratinisation of the ductal epithelium, keratinised cell debris and increased meibum viscosity
- causes normal clear oily secretions to become semi-solid, toothpase like plaques
what kind of populations are most likely to have MGD?
mainly asian populations
what is the vicious cycle for dry eye disease?
- damage to ocular surface
- goblet cell loss
- mucin loss
- tear film instability
- excessive tear evaporation
- hyperosmolarity
8.inflammation - keratinisation of gland orfices
which causes inflammation and the cycle repeats
what is the cycle for MGD?
- bacterial proliferation causes increased exotoxin release
- lipases and esterases destabilise the tear films lipid layer
- this causes a rise in meibum melting point
- which causes meibomian gland dysfunction
which leads to proliferation of bacteria and the cycle repeats
What are the consistent risk factors for Dry eye?
-increasing age
-CL wear
-being female
-Asian ethnicity
what are the signs of dry eye?
-fluorescein staining, small tear meniscus height, TBUT <10
what are the symptoms of dry eye?
-discomfort
-dryness
-irritation
-grittiness
-fluctuating vision which may get worse throughout the day
-vision that gets worse with wind, smoke, heat and prolonged near activities
how do you diagnose dry eye?
-use the dry eye questionnaire to determine if they have symptoms of dry eye (difficult if time is limited)
-check tear film stability, tear film osmolarity or ocular surface staining
-check tear meniscus
how do you manage dry eye?
-dietary advice of eating more oily fish for omgea 3
-recommend ocular lubricants such as preservative free artificial tears
-wear protective glasses/ moisture chamber glasses
-use specialist care methods if these don’t work
-refer to secondary care if nothing else works
what specialist care methods can be used when treating dry eye?
-punctum plugs
-scleral / bandage contact lenses
-pharmacological management like topical steroids
what could be differential diagnoses to dry eye?
computer vision syndrome and digital eye strain
what are the risk factors for MGD?
-wearing CLs
-prolonged screen use (as it reduced blink rate)
what are the signs of MGD?
-changes to secretion of the gland
-saponification of tears
-gland plugging/ paste like yellowish secretion
diagnosis of MGD
-inspect the glands for the signs
-push on the meibomian glands to clear the blockage
MGD treatment?
squeeze the meibomian glands to clear the blockage
MGD management?
- use products to heat your eyes like heated eye mask
- massage the eyelids to clear the blockages
- clean the eyelids
in MGD when should you refer to secondary care?
-sometimes when you have peads px
-if they may have suspected underlying conditions or unidentified systemic diseases
-secondary complications like vascularisation, corneal scarring and infection
-abnormal lid anatomy/ function
-persistent/ severe Sx that dont want to respond to primary management after 4-12 weeks
Name two types of corneal inflammation
-marginal keratitis
-CL associated infiltrative events (CIE’S)
what is the aetiology of marginal keratitis?
an inflammatory response of the peripheral cornea to bacteria exotoxins instead of direct inocculation
what are the predisposing factors
-bacterial blepharitis
-sometimes contact lenses
what are the signs of marginal keratitis?
-redness and inflammation of limbus and bulbar conjunctiva due to excess blood in the vessels
- stromal infiltrate ( typically adjacent to the limbus and separated
by an interval of clear cornea)
-ulcers (they stain with fluorescein)
what are the symptoms of marginal keratitis
-ocular discomfort
-lacrimation
-red eye
-photophobia
what is the non pharmacological management of marginal keratitis?
-initially address predisposing factors e.g. contact lenses
-regular lid hygiene for associated blepharitis
what are the pharmacological managements for marginal keratitis?
-ocular lubricants for symptomatic relief
-systemic analgesia when needed (painkillers)
-topical antibiotic use to reduce bacterial load plus topical steroid to reduce inflammation
Name three CIEs
-contact lens-associated peripheral ulcer (CLPU)
-contact lens associated infiltrative keratitis
-contact lens associated acute red eye (CLARE)
what is the aetiology for CIEs?
a self limiting inflammatory response of the cornea affecting the anterior stroma
what are the patient related pre disposing factors of CIEs?
-blepharitis
-male sex
-being <25 years old
-smoking
-having previous Hx of CIEs
what are the predisposing factors of CIEs for patients who wear CLs?
-long term lens wear
-overnight wear
-silicon hydrogel material
-tight fit lens
-MSPs
-poor lens hygiene
what are the symptoms of CIEs?
-red and watery eye
-foreign body sensation
-photophobia
(some cases are even asymptomatic)
what are the signs of CIE’s?
-peripheral anterior stromal infiltrates, usually small
-ulcer formation
-conjunctival hyperaemia
-adjacent limbal hyperaemia
-epiphoria
-anterior chamber inflamed to some degree
-usually unilateral
Give the non-pharmacological management of CIE’s
- address the modifiable risk factors
-temporarily discontinue lens wear as this can resolve signs and symptoms within 48 hrs
-advise against extended CL wear
-evaluate lens fit and care regime
-reinforce education concerning lens hygiene and wearing schedules
-warn about possibility of recurrence as if condition recurs, then switch to daily disposables
-lid hygiene if blepharitis is present
give the pharmacological management of CIEs
-ocular lubricants for symptomatic relief
-topical antibiotic may be indicated if blepharitis present
what is the aetiology of bacterial keratitis
sight threatening infection of the cornea
what are the most commen bacterial corneal pathogens with their types
-Pseudomonas sp. (Gram -ve)
-Staphylococcus sp. (Gram +ve)
-Streptococcus sp. (Gram +ve)
What are the predisposing factors of bacterial keratitis?
- Contact lens wear
- Ocular surface disease, ocular trauma/surgery
- Immunocompromised
- Lid margin infection
What are the most common fungal corneal pathogens?
-Candida sp. (yeast-like)
-Fusarium sp. (filamentous)
- Aspergillus sp (filamentous)
what are the predisposing factors of fungal keratitis specifically?
-being immunocompromised
-having had a trauma involving organic materials
what are signs that are specific to fungal keratitis?
-deep lesions with a feathery edge
-raised profile
-satellite lesions
-endothelial plaque
what are the symptoms of bacterial/ fungal keratitis?
-pain (usually acute onset and quickly gets worse)
-redness
-photophobia
-blurred vision (if lesion is on visual axis)
-discharge
-yellow spot on cornea
what are the signs of both bacterial/ fungal keratitis?
*Lid oedema
* Epiphora
* Discharge (mucopurulent or purulent)
* Conjunctival hyperaemia and infiltration
* Corneal lesion usually single (central or mid-
peripheral)
* Excavation (cavity) of epithelium, Bowman’s layer, stroma
(tissue necrosis)
* Stromal infiltration beneath lesion
* Stromal oedema with folds in Descemet’s
membrane
* Anterior chamber activity (flare, cells, hypopyon or
coagulum if severe)
what is the non-pharmacological management of bacterial/ fungal keratitis?
remove CLs but keep them and the case to determine the culture)
what are the non pharmacological management techniques of bacterial/ fungal keratitis?
-emergency referral to secondary care
what are the predisposing factors of acanthamoeba keratitis?
-wearing CLs
-* inadequate contact lens disinfection
* use of non-sterile solutions
* tap water rinsing of lenses and/or storage cases
* contamination of storage case with bacteria and fungi (± biofilm) which provide substrate for
Acanthamoeba
* exposure to shower, pool, or hot tub water
-corneal trauma with exposure to soil or contaminated water
what are the symptoms of AK?
*Pain (may be severe and out of proportion to degree of ocular inflammation; may also be painless in the early stages)
* Visual disturbance/loss, Redness, Watery eye, Photophobia
* May be a long history and condition may be misdiagnosed as herpetic, bacterial or fungal keratitis
what are the signs of AK?
-conjunctival and limbal hyperaemia
-epiphoria
-reduced VA in later stages
what are the early signs of the corneal lesions of AK?
*punctate epitheliopathy
* epithelial or subepithelial infiltrates
* pseudodendrites
* radial keratoneuritis (infiltrates along corneal nerves)
* recurrent breakdown of the corneal epithelium
what are the later signs of corneal lesions of AK?
- deep inflammation of the cornea consisting of a central
or paracentral ring-shaped or disciform stromal infiltrate
or abscess - stromal thinning
- extension of inflammation into sclera
- anterior chamber cells and flare
- hypopyon (inflammatory cells in anterior chamber of eye)
what is management for AK?
-remove CLs
-refer to secondary care EMERGENCY
what are the two types of viral keratis?
hepes simplex keratitis and herpes zoster ophthalmicus
What are the two types of of Herpes simplex virus? (HSV)
HSV-1 mainly infects mucous membranes ‘above the waist’
HSV-2 mainly infects mucous membranes ‘below the waist’
what are the predisposing factors of HSK?
- Poor general health, immunodeficiency, fatigue, steroids, immunosuppressive drugs, previous HSV
infection - Aggravating factors – UV light, fever, extreme heat/cold, infection, trauma
what are the symptoms of HSK?
- Usually unilateral, rarely bilateral
- Variable symptoms, can include pain, burning, irritation, photophobia, blurred vision, redness, reduced
VA
what are the epithelial signs of HSK?
-Initial punctate lesions, coalescing into a dendriform pattern
-* Dendritic ulcer, single or multiple opaque cells arranged in a stellate pattern progressing
to a linear branching ulcer, terminal bulbs may be visible
* Dendritic lesions stain with fluorescein
* Associated with reduced corneal sensitivity
what are the stromal signs of HSK?
- Stromal infiltrates, vascularization, oedema and opacification
- Non-necrotising oedma is localized & often self-limiting,
- Necrotizing inflammation is widespread, infection progressed to ulceration, necrosis and
possible perforation
what is the most severe sign of HSK?
metaherpetic ulcer
what is the management for herpes simplex keratitis?
- Aciclovir 3% ointment (continue for 3 days after healing complete)
- Gangiclovir 0.15% ophthalmic gel (continue for 7 days after healing complete)
*emergency referral if the stroma is involved or the Px is a child, contact lens wearer or has bilateral infection
what is herpes zoster infection?
involvement of the ophthalmic division of the trigeminal nerve due to infection
what microbe causes HZO?
human herpes virus -3 (HHV-3)
what are the predisposing factors of HZO?
-age
-being immunocompromised
what are the symptoms of HZO?
- Pain and altered sensation (often described as “tingling“, “burning” or
“shooting”) of the forehead on one side - Rash affecting forehead and upper eyelid appears a day to a week later
General malaise, headache, fever - Ocular symptoms in acute phase: discomfort, discharge, redness, pain,
photophobia
what are the signs on the skin with HZO?
- unilateral painful, red, vesicular rash on the forehead and upper eyelid, does
not cross the midline, crusts after 2-3 weeks - Hutchinson’s sign, (indicating nasociliary nerve involvement) skin lesions on the side of the tip of the nose, correlates strongly with ocular involvement.
What are the ocular signs of HZO?
*Early onset or within one month after the onset of the skin rash therefore
patients need to be monitored
* Mucopurulent conjunctivitis (common), associated with vesicles on the lid
margin; usually resolves within 1 week
* keratitis causing punctate epithelial – early sign, pseudodendrites – fine, multiple stellate lesions (around 4-6 days), disciform – 3 weeks after the rash (occurs in 5% of cases), reduced corneal sensation (neurotrophic keratitis), occurring in approximately 13% of HZ keratitis cases
* Episcleritis occurs in around one third of cases
for HZO, what is the management?
-advice avoidance of contact with elederly, pregnant or immunocompromised people
-advice good diet and lots of fluids
-topical lubricant for ocular symptoms
-pain relief like paracetamol
-emergency referral to GP for systematic anti viral treatment for acute skin lesions as this will reduce percentage of eye disorders if this gets treated within 72hrs of onset
-maintain low threshold to refer to secondary care