4- Ophthalmology (others) Flashcards
Herpes zoster ophthalmicus
Background (Trigeminal herpes)
- Commonly known as shingles
- Viral disease characterised by unilateral painful skin rash in one or more dermatone distributions of the trigeminal nerve e.g. opthalmic division (5th cranial nerve)
o Shared by the eye and ocular adnexa
pathophysiology of ophthalmic shingles
- Commonly known as shingles
- Viral disease characterised by unilateral painful skin rash in one or more dermatone distributions of the trigeminal nerve (5th cranial nerve)
o Shared by the eye and ocular adnexa
Risk factor of ophthalmic shings
- Older adults
- Immunosuppression e.g. HIV, immunosuppressive drug
presentation of ophthalmic shingles
- Erythematous skin lesions with macules, papules, vesicles, pustules, crusting lesions in the distribution of the trigeminal nerve
- Hutchison’s sign
- symptoms: fever, malaise, headache, eye pain prior to eruption of skin
Hutchison’s sign
– skin lesions at the tip, side or root of nose
o Strong predictor of ocular inflammation and corneal denervation in HZO
investigations for ophthalmic shingles
Investigations
- Visual acuity e.g. Snellen chart
- External examination of eyelids, periocular skin and scalp
- Measurement of intraocular pressure
- Slit lamp bio microscopy of anterior segment
- Fluorescein staining
- Dilated examination of lens, macular, peripheral retina, optic nerve and vitreous
- Corneal scrapings of any skin lesions -> Tzanck smear
management of ophthalmic shingles
- Oral acyclovir 800mg PO five times daily for 7 to 10 days
- Topical steroids should be used for interstitial keratitis and uveitis
- If increased intraocular pressure found in herpes trabeculitis -> topical steroids should be administered as well as aqueous suppressants (e.g. timolol, brimonidine, dorzolamide, acetazolamide)
- Neuropathic pain -> amitriptyline or pregabalin
- Antibiotic cream if rash infected
- Surgery : if cornea thinning and loss of structural integrity of eye -> cornea transplantation
Posterior Vitreous Detachment Background
- Where the vitreous gel comes away from the retina
- Vitreous body is the gel inside the eye that maintains the structure of the eyeball and keeps the retina pressed against the choroid
- Made up of: collagen and water
Very common in older adults
pathophysiology of posterior vitreous detachment
- With age the vitreous body becomes less firm and less able to maintain its shape
- Posterior vitreous detachment is a condition where the vitreous gel comes away from the retina-> vitreous collapses anteriorly towards the vitreous base
Risk factor/causes of posterior vitreous detachment
- Older age
o Most eyes by eighth decade of life - Increased axial length of the eye = Myopic eyes (near sightedness)
posterior vitreous detachment presentation
Presentation
- Painless
- May be asymptomatic
- Symptoms may include
o Spots of vision loss
o Floaters
o Flashing lights
Investigations posterior vitreous detachment
- Slit lamp to exclude retinal tears or detachment
- Thorough assessment of the retina usually done by optometrist or ophthalmologist
management of posterior vitreous detachment
No treatment necessary -> symptoms improve as brain adjusts
Posterior vitreous detachment can predispose patients to developing
retinal tears and retinal detachment.
Blepharitis
Background
- Inflammation of the eyelid margins
- Can be associated with dysfunction of the meibomian glands -> lead to styes and chalazions
blepharitis presentation
Presentation
- Gritty
- Itchy
- Dry
Stye vs chalazion
- A chalazion is a blocked oil gland that appears on the inside of the eyelid, usually surfacing as a bump.
- An eye stye (or hordeolum) is a smaller pimple-like bump that appears on the upper or lower eyelid due to a blocked oil gland. It is typically near the eyelash and lives on the outside of the eyelid.
o Infection
management of chalazion
- Hot compress, massage and analgesia
- Consider topical antibiotics e.g. chloramphenicol if acutely inflamed
summary of glands of the eyelids and eyelid disease
trichiasis
- Inward growth of eyelashes
- Results in pain and can cause corneal damage and ulceration
symptoms of trichiasis
Ectropion
Background
- Where the eyelid turns outwards with the inner aspect of the eyelid exposed -> usually bottom lid
- Can result in exposure keratopathy
- Can be cause by aging
Entropion
Background
- where the eyelid turns inwards with the lashes against the eyeball
- results in corneal damage and ulceration
- aging is a main cause
