Refractive errors - Cataract - Glaucoma Flashcards
Refractive errors - correctable or not?
correctable with glasses
Refractive errors - types
- Hyperopia
- Myopia
- Astigmatism
- Presbyopia
hyperopia - mechanism
Eye too short for refractive power of cornea and lens
–> light focused behind retina
Myopia - mechanism
eye too long for refractive power of cornea and lens –> light focused in front of retina
Astigmatism - mechanism
abnormal curvature of cornea –> different refractive power at different axis
Presbyopia - mechanism
Age - related impaired accommodation (focusing on near objects), 1ry due to decreased lens elasticity
Cataract - definition
opacification of lens
Cataract - unilateral or bilateral / type of pain
- often bilateral
- painless
Cataract often results in
decreased vision
Cataract - risk factors (10)
- increased age 2. ethanol 3. prolonged corticosteroid use 4. Diabetes mellitus (sorbitol) 5. trauma 6.smoking 6. excessive sunlight 7. infection
- 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)
Uveitis - definition
inflammation of uvea
uveitis is divided to (according the place) (AKA)
- anterior uveitis (iritis)
- intermediate uveitis: pars planitis
- posterior uveitis (choroiditis and/or retinitis)
Uveitis may have - symptoms/findings
- hypopyon (accumulation of pus in anterior chamber)
2. conjuctival redness
Uveitis is associated with
systemic inflammatory disorders:
- Sarcoidosis 2. Rheumatoid arthritis 3. juvenile arthritis
- Bechet disease 5 . HLA-B27
HLA associated with Uveitis
HLA-B27
optic disc is AKA
optic nerve head
optic disc is
the point of exit for ganglion cell axons leaving the eye.
The optic disc is shaped like a (and why)
doughnut with a pink neuroretinal rim and a central white depression called the physiologic cup.
Glaucoma - definition
optic atrophy with characteristic cupping, usually elevated intraocular pressure and progressive peripheral visual field loss
Glaucoma - characteristic cupping
thinning of outer rim of the optic nerve head versus normal
Glaucoma - intraocular pressure
usually elevated
glaucoma is divided to
- open angle
2. closed angle
open angle glaucoma is associated with
- increased age
- African american race
- family history
open angle glaucoma is divided to
- primary
2. secondary
causes of primary open glaucoma
unclear
causes of secondary open glaucoma
blocked trabecular meshwork from
a. WBC (eg uveitis)
b. RBCs (eg vitreous hemorrhage)
c. retinal elements (eg retinal detachment)
open angle glaucoma special characteristic
PAINLESS
closed/narrow angle - divided to
- primary 2. secondary
or - chronic closure 2. acute closure
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
secondary closed/narrow angle - mechanism
hypoxia from retina disease (diabetes mellitus, vein occlusion) –> vasoproliferation in iris that contracts the angle
disease associated with secondary closed/closed narrow angle
- diabetes mellitus
2. vein occlusion
chronic closed/narrow angle - symptoms and findings
- often asymptomatic
- damage to optic nerve
- damage to peripheral vision
acute closed/narrow angle is a ….
true ophthalmic emergency
acute closed/narrow angle - mechanism
elevated intraocular pressure pushes iris forward –> angle closes abruptly
acute closed/narrow angle - do not give (and why)
epinephrine because of its mydriatic effect
acute closed/narrow angle - symptoms and signs
- very painful
- red eye
- sudden vision loss
- halos around halos
- rock hard eye
- frontal headache
congenital risk factors for cataract a. classic galactosemia, b. galaktokinase deficiency, c. trisomies (13, 18, 21),
d. Torches infection, e. Marfan f. Alport g. Mytonic dystrophy h. Neurofibromatosis 2)
a. classic galactosemia, b. galaktokinase deficiency, c. trisomies (13, 18, 21), d. Torches infection e. Marfan f. Alport g. Mytonic dystrophy h. Neurofibromatosis 2
Conjunctivitis - definition/presentation
inflammation of the conjuctiva –> red eye
Conjunctivitis - types and presentation (and MC)
- Allergic –> itchy eyes
- Bacterial –> pus
- Viral (MC)–> sparse mucous discharge, swollen preauricular node
Conjunctivitis - treatment
bacterial –> antibiotics
viral –> self resolving
viral conjunctivitis is often due to
adenovirus
allergic conjunctivitis - characteristic
bilateral
Viral vs bacterial conjunctivitis - transmissible
Virus easy
Bacterial poorly
Viral vs bacterial conjunctivitis - adenopathy
Only virus (preauricular)
characteristics of Viral conjunctivitis
bilateral, Watery discharge, easily transmissible, normal vision. itchy, preauricular adenopathy, no specific therapy
characteristics of Bacterial conjunctivitis
unilateral, purulent + thick discharge, poorly transmissible, normal vision, not itchy, no adenopathy, topical antibiotics
red eye (opthalmologic emergencies) - types and presentation
- conjunctivitis: itchy eyes with discharge
- uveitis autoimmune disease
- glaucoma: pain
- abrasion: trauma
red eye (opthalmologic emergencies) - types and eye findings
- conjunctivitis: normal pupil
- uveitis: photophobia
- glaucoma: fixed midpoint pupil
- abrasion: like sand in the eye
red eye (opthalmologic emergencies) - types and most accurate test
- conjunctivitis: clinical diagnosis
- uveitis: slit lamp examination
- glaucoma: tonometry
- abrasion: fluorescein stain
red eye (opthalmologic emergencies) - types and best initial therapy
- conjunctivitis: topical antibiotics
- uveitis: topical steroids
- glaucoma: acetazolamide, mannitol, pilocarpine, laser trabeculoplasty
- abrasion: no specific therapy, patch not clearly beneficial
glaucoma treatment if medical treatment fails
laser trabeuloplasty
it can precipitate closed angle glaucoma
walking into a dark rook can precipitate pain because of pupillary dialation (SOS)
acute angle-closure glaucoma - the diagnosis is confirmed by
tonometry
acute angle-closure glaucoma - treat with (and why)
- IV acetazolamide
- IV mannitol: osmotic driving of fluid out of the eye
- Pilocarpie, beta-blockers and apracloinidine to constrict the pupil and enchance and enchance drainage)
- laser iridotomy
keratitis - definition / presentation
infection of cornea
the eye may be very red, swollen and painful, but do not use steroids
hepres keratitis - never use …. (why)
steroids –> make it worse / increase the production of the virus
hepres keratitis - diagnosis
Fluorecein staining of the eye helps confirm the dendritic pattern seen on examination
hepres keratitis - treatment
oral acyclovir, famciclovir or valacyclovir
topical anthepretic treatment is trifluridine and idoxuridine
Cataracts - diagnosis
early Cataracts: ophthalmoscope or slit lamp exam
advanced: visible on examination
- Hypertropia is corrected by
2. myopia is corrected by
- convex lens
2. biconcave lens
- astigmatism is corrected by
2. presbyopia is corrected by
- cylindric lens
2. convex lens
