Refractive errors - Cataract - Glaucoma Flashcards Preview

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Flashcards in Refractive errors - Cataract - Glaucoma Deck (61)
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1

Refractive errors - correctable or not?

correctable with glasses

2

Refractive errors - types

1. Hyperopia
2. Myopia
3. Astigmatism
4. Presbyopia

3

hyperopia - mechanism

Eye too short for refractive power of cornea and lens
--> light focused behind retina

4

Myopia - mechanism

eye too long for refractive power of cornea and lens --> light focused in front of retina

5

Astigmatism - mechanism

abnormal curvature of cornea --> different refractive power at different axis

6

Presbyopia - mechanism

Age - related impaired accommodation (focusing on near objects), 1ry due to decreased lens elasticity

7

Cataract - definition

opacification of lens

8

Cataract - unilateral or bilateral / type of pain

- often bilateral
- painless

9

Cataract often results in

decreased vision

10

Cataract - risk factors (10)

1. increased age 2. ethanol 3. prolonged corticosteroid use 4. Diabetes mellitus (sorbitol) 5. trauma 6.smoking 6. excessive sunlight 7. infection
8. congenital risk factors (a. classic galactosemia, b. galaktokinase deficiency, c. trisomies (13, 18, 21),
d. Torches infection, e. Marfan f. Alport g. Mytonic dystrophy h. Neurofibromatosis 2)

11

Uveitis - definition

inflammation of uvea

12

uveitis is divided to (according the place) (AKA)

1. anterior uveitis (iritis)
2. intermediate uveitis: pars planitis
3. posterior uveitis (choroiditis and/or retinitis)

13

Uveitis may have - symptoms/findings

1. hypopyon (accumulation of pus in anterior chamber)
2. conjuctival redness

14

Uveitis is associated with

systemic inflammatory disorders:
1. Sarcoidosis 2. Rheumatoid arthritis 3. juvenile arthritis
4. Bechet disease 5 . HLA-B27

15

HLA associated with Uveitis

HLA-B27

16

optic disc is AKA

optic nerve head

17

optic disc is

the point of exit for ganglion cell axons leaving the eye.

18

The optic disc is shaped like a (and why)

doughnut with a pink neuroretinal rim and a central white depression called the physiologic cup.

19

Glaucoma - definition

optic atrophy with characteristic cupping, usually elevated intraocular pressure and progressive peripheral visual field loss

20

Glaucoma - characteristic cupping

thinning of outer rim of the optic nerve head versus normal

21

Glaucoma - intraocular pressure

usually elevated

22

glaucoma is divided to

1. open angle
2. closed angle

23

open angle glaucoma is associated with

1. increased age
2. African american race
3. family history

24

open angle glaucoma is divided to

1. primary
2. secondary

25

causes of primary open glaucoma

unclear

26

causes of secondary open glaucoma

blocked trabecular meshwork from
a. WBC (eg uveitis)
b. RBCs (eg vitreous hemorrhage)
c. retinal elements (eg retinal detachment)

27

open angle glaucoma special characteristic

PAINLESS

28

closed/narrow angle - divided to

1. primary 2. secondary
or
1. chronic closure 2. acute closure

29

primary closed/closed narrow angle - mechanism

enlargement or forward movement of lens against central iris (pupil margin) --> obstruction of normal aqueous flow through pupil --> fluid builds up behind iris, pushing peripheral iris against cornea and impeding flow through trabecular meshwork

30

secondary closed/narrow angle - mechanism

hypoxia from retina disease (diabetes mellitus, vein occlusion) --> vasoproliferation in iris that contracts the angle