Week 1 Flashcards
(103 cards)
Rods are sensitive to low/high levels of light and function for night vision and peripheral vision/colour vision
Cones function for night vision and peripheral vision/colour vision and acuity/seeing far off things
Rods - low levels of light, night vision/peripheral vision
Cones - colour vision and visual acuity
What are the 7 extra ocular muscles?
What is the mnemonic to remember which nerves supply which muscles?
Lateral rectus
Medial rectus
Superior rectus
Inferior rectus
Superior oblique
Inferior oblique
Levator palpebrae superioris
LR6 SO4 AO3

What are the different types of refractive error?
Myopia - short-sighted
Hyperopia - long-sighted
Astigmatism
Presbyopia
When taking a history from a patient, what symptoms would you ask about that are specific to vision? What other questions might you ask if taking an ophthalmic history?
Glare
Distortion
Photophobia
Flashing lights/floaters
Oscillopsia
Diplopia
Pain? Discomfort/dryness? Red/swollen? Itch? Discharge/watering?
What are some causative organisms of bacterial conjunctivitis in…
- neonates?
- other ages?
Neonates - Staph aureus, Neisseria gonorrhoea, Chlamydia trachomatis
Other ages - Staph aureus, Strep pneumoniae, Haemophilus influenzae
Bacterial conjunctivitis - treatment
Swab
Topical antibiotics - usually Chloramphenicol (drops or ointment) (Avoid Chloramphenicol if patient has a history of aplastic anaemia/allergy)
What cause of viral conjunctivitis is commonly associated with a preceding URTI?
Adenovirus
What are some of the features of chlamydial conjunctivitis?
Often chronic history
Unresponsive to treatments
May or may not have symptoms of urethritis, vaginitis
Suspect if bilateral conjunctivitis presents in young adults
What clinical signs will be present in someone with bacterial keratitis? How is it treated?
Big area clouding the cornea
Hypopyon - line of bacterial film along the bottom of the cornea, sight-threatening
Require admission for hourly drops of antibiotics and daily review

What are the causes of viral keratitis? Which is more common? What clinical features would be seen?
Herpes simplex (most common)
- Dendritic ulcer
- Very painful
- May be recurrent, becoming less painful as the sensation in the cornea lessens DONT TREAT WITH STEROIDS
Adenoviral
- Bilateral, usually following a URTI contagious
- May affect vision
- May give topical antibiotics prophylactically, and steroids CAN be used to speed up recovery

What fungi can cause keratitis? What are they associated with?
Acanthomoeba and Pseudomonas aeruginosa
Associated with contact lenses and a history of trauma associated with vegetation e.g. Farmers
Describe Orbital Cellulitis, what condition it’s commonly associated with, and what precaution needs to be taken regarding investigation.
Cellulitis of septum (due to focal Orbital infection/post-operative) resulting in compartment syndrome and an increase in orbital pressure
Causes pain, especially on eye movements, proptosis (as a severe complication), pyrexia, is often associated with paranasal sinusitis and can be sight-threatening
CT scan needs to be performed to identify orbital abscess and determine if pre- or post-septal
What are the causative organisms of orbital cellulitis? What is the treatment?
Staphylococcus
Streptococcus
Coliforms
Haemophilus influenzae
Anaerobes
V broad spec antibiotics given and patient monitored closely. May require drainage. If there is any indication of restriction of muscles or optic nerve dysfunction then scan
What is endophthalmitis? What is the most common causative organism and how is it treated?
“Devastating” infection within the eye, very painful, very red eye, decreasing vision and sight threatening
Can be endogenous (often common commensals, Staph epidermidis being most frequent) or POST-OPERATIVE - major concern associated with surgery
Treatment - intravitreal amikacin/ceftazidime/vancomycin
What is chorioretinitis? What causes it?
Infection at the back of the eye
Causes
- CMV in HIV patients (pizza pie appearance)
- Toxoplasma gondii
- Toxocara canis
What antibiotics are commonly used in eye infections?
Chloramphenicol - inhibits peptidyl transferase, side effects include allergy, aplastic anaemia and “grey baby syndrome”
Penicillins and cephalosporins
Quinolones e.g. Ofloxacin inhibit DNA gyrase = cell death. Only used in bacterial keratitis
Fusidic acid - used to treat Staph aureus
Gentamicin - treats gram negatives including Pseudomonas
What substance can be used to better investigate ocular trauma?
Fluorescein drops
What is the name given to a fluid level of blood in the anterior chamber?
Hyphaema

What group is retinal detachment more common in?
Myopes (short-sighted people)
What is the term given to a bruised retina?
Commotion retinae
What is Seidel’s test?
After applying fluorescein to an injured eye, it can be seen to dilute as fluid passes out of the sight of injury
What is sympathetic ophthalmia?
Exposure of one eye to antigens causes an immune reaction and subsequent Inflammation in both eyes
Can result in bilateral blindness from a unilateral injury, extremely rare
What should ALWAYS be done if an intra-ocular foreign body is suspected?
X ray orbits
What is of more concern when considering the eye - acid or alkali burns? Why?
Alkali burns - easy, rapid penetration into eye and continues to burn through structures. Concern is limbus ischaemia
Acid - less worrying, causes proteins to coagulate and there is little penetration























