opthamology Flashcards Preview

Block 6 > opthamology > Flashcards

Flashcards in opthamology Deck (25):
1

vision loss

what can go wrong?

1. focused light doesnt reach the retina

2. the retina doesnt turn it into nerve impulses

3. the optic nerve doesnt tranmit the impulses to the brain

4. Brain doesnt precess them correctly

2

Cornea function

- transmission of light into the eye

- refraction of light

3

optics of eye

emmetropia

- normal eye

hyperopia

- flat cornea, light not focused til behind eye

- farsighted

Myopia

- steep cornea

- near sighted

4

cornea 

major abnormalities

1. epitheliopathies (disruption, edema)

2. stromal opacities

- scarring

- edema (endothelial cell dysfunction)

3. irregular shape

5

cornea

clinical disorders

1. keratitis sicca

2. infectious keratitis

3. peripheral ulcerative keratitis (RA)

4. Pseudophakic corneal edema

5. keratoconus

6

cornea

symotoms

1. everything is white(opacities)

2. colored haloes (edema)

3. distortion (irregularities)

4. ghost images (refractive errors, epitheliopathies)

7

ocular surface

definition:

important functions:

def:

- outer surface of globe

- inner surface of eyelid

imp functions:

- protects eye from exogenous factors

- maintains moist surface

8

ocular surface 

clinical disorders:

 

1. primary corneal disease

2. dry eyes

- aqeous tear dificiency

- tear dysfunction

3. conjunctival disease

 

9

Eyelids

function:

major abnormalities:

function:

 1. protect ocular surface

2. meaintain normal tear film 

 

major abnormalities:

1. structural defects (tumors)

2. entrpion (trichiasis)

3. Ectropion/ eyelid laxity

4. dysfunction (lagophthalmos, ptosis)

5. weakness

10

anterior segment

diseases:

1. diseases reduce vision by affecting function of other tissues

- glaucoma

- inflammation (uveitis)

2. most anatomic changes dont affect vision directly

except: 

- opacified media (blood, fibrin)

- membranes

- cataracts

11

lens

functions:

 

major abnormalitie

function:

1. transmission of light

2. additional focus of light

3. accomodation- (change focus for near vision)

 

major abnormalities:

1. dislocation

2. opacification (cataract)

3. swelling (change in refractive state)

4. hardening (failure to change shape; lack of accomodation)

12

lens

symptoms:

1. poor quality of vision (poor color vision, altered contrast sensitivity)

2. poor focus

3. glare, ghost images

4. "foggy vision", "haze"

13

Retina

major abnormalities:

1. loss of tissue (infection, degeneration)

2. edema

3. disturbances of normal position

- traction 

- retinal detachment

14

retina

symptoms:

1. scotomata (blind spots), curtains

2. poor quality

3. blurring

4. patchy loss

5. metamophopsia (distortion)

 

15

international ocular infections

 

1. trachoma

2. onchocerciasis

3. leprosy

16

conjencitivitis 

basic concepts

 

- red eye with no pain or decreased vision

- cornea is clear with good light reflex

- if pain or decreased vision, think:

- corneal ulcer

- anterior uveitis

- acute (narrow angle) glaucoma

17

conjunctivitis- etiologies

 

1. allergic

- itching

- hx od atopy

- mucus

2. bacterial

- mucopurulent

- +/- adenopathy

- patential souce

3. viral

- acute onset

- hx of exposure/ contact

- mucus

- preauricular adenopathy

18

epidemic conjunctivits

- caused mainly by adenovirus type 8,19,37

- others- coxsackie, enterovirus, strep pneumoniae

- 10-14 days

- can be infectious for 3 weeks (pre and after)

- highly contagious

19

hemorrhagic conjunctivitis

- unilateral or bilateral

- may be associated with prodromal symtoms

- confluent subconjenctival hemorrhage

- caused by enterovirus or coxsackievirus

- highly contagious

20

herpetic viral conjunctivitis

- primary infection at any age

- unilateral

- vesicular skin lesions on primary presentation

- corneal inveolvement with classic dendrite

- keratitis may worsen with topical steroids

- uveitis

- recurrence common

21

organisms that cause ocular infections

viral: adeno, coxsackie, herpes simplex, herpes zoster, varicella, CMV, RSV

Bacterial: strep, staph, pseudomonas, neisseria, syphilis, borrelia (lyme disease)

chlamydial:trachoma

mycoplasma: TB, leprosy, atypial forms

fungal: mucomycosis, candida

protasoan and nematodes: acanthamoeba, filariasis, toxoplasmosis, toxocara

22

method of ocular infection and spread

1. direct contact with or without disruption of normal protective bariers

2. direct spread (sinus infection)

3.opthalmia neonatorum

- chemical (24hrs), N. gonorrhea (4 days), chlamydia (3 wks), herpes simplex

4. hematogenous

- retinal and choroidal infections

embolic- endocarditis, meningitis, fungemia

5. iatrogenic- surgical and intravitreal

6. trauma

7. aerosol

23

bacterial conjunctivitis

- preschool age

- bilateral or unilateral

- mucopurulent discharge

- otitis media association

24

most common pediatric causes of acute conjenctivitis

- haemophilus influenzae

- strep pneumoniae

- moraxella catarrhalis

25

delivery of ocular therapy

1. topical (drops or ointment)

2. intravitreal injections

3. systemic