Ophthalmology Flashcards
What are the causes of blepharitis
staph infection, meibomian gland dysfunction, seborrheic dermatitis
draw the visual defect diagram
(check online)
what is homonymous hemianopia
when the visual field defect is on the same side on each eye eg the left
what is heteronymous hemianopia
bitemporal/binasal- half a visual field is lost
what is the outer layer of the eye called
sclera
what structures influence the length of the lens
ciliary bodies, suspensory ligaments
what is the jelly like fluid infront of the pupil covered with?
cornea
what is the layer under the sclera
choroid
what is the innermost layer of the eye called
retina
what is the spot at the back of the eye called that is specialised for visual acuity
fovea
what photo receptor cells does the fovea contain? what are their function?
cones, colour vision
function and location of meibomian glands
oil production which prevents eyes from drying out– line the margin of the eye lids (where eyelashes are)
sx of blepharitis
gritty eyes burning sensation conjunctival redness ****loss of eyelashes recurrent lid lumps (chalazion, styes) *****worse in the morning
what other conditon may blepharitis be associated with? tx?
may be assoc with Rosacea (Skin condition with redness/flushing/telangiestasia/pustules on the face)- tx with metronidazole
Blepharitis Management
hygiene
1. warm massage of the eyelids
***tear substitutes
chloramphenicol ointment 1%
What is a chalazion
Meibomian Cyst, due to gland blockage
sx of chalazion
swelling on eyelid
PAINLESS
may start as a stye (painful)
often not quite on lashline and on upper eyelid
tx of chalazion
hot compress
gentle massage of the gland
safety net periorbital cellulitis- change in vision, very painful/uncomfortable, fever
if not resolved within 4w- refer
what is UL blepharitis a red flag for
tumour
sx of a stye
small lump on the lash line
angry, tender, red lump, uncomfortable
what is a stye
infection of a lash follicle- usually staph
What are the most common causative organsisms of Periorbital cellulitis
Staph aureus, H.influenzae type B- often follows URTI
sx of periorbital cellulitis
systemically unwell
often a child
fever
erythema, tenderness around the eyeball
tx periorbital cellulitis
5-7 day course of abx
adults- co-amox 500/125mg TDS for 1 week/clarithro 500mg BD for 1 week with metronidazole
children- fluclox 125mg QDS for 1 week/coamox
incision an ddrainage
referral to paeds, ENT, MDT