Diseases of the Eye Flashcards
Xeropthalmia: where does it occur
- primarily in developing country due to diet low in vitamin A
Why does vitamin A cause xeropthalmia
- vitamin A necessary for cells of conjunctiva, which produce mucus of tear film
Xeropthalmia: disease process
- chronic reduction in corneal tear film leads to loss of corneal transparency and in growth of blood vessels
Xeropthalmia is exacerbated by what disease in children
- measles
Treatment for Xeropthalmia
- limited
- corneal transplant results are poor
Other effect seen in Xeropthalmia
- vitamin A deficiency also affects rod photoreceptors, can lead to night blindness
Similar outcomes of xeropthalmia due to other causes
- observed in individuals with chemical or thermal corneal burns or chronic breakdown of corneal epithelium (dry eye, diabetes complications)
Keratoconus: incidence & who it effects
- incidence: 1/2000; typically BILATERAL
- associated with down syndrome, marfan syndrome
Keratoconus: disease process
- progressive thinning and ectasia of the cornea; occurs in ABSENSE of inflammation of vascularization
- results in a cornea with a conical shape
Treatment for keratoconus & exacerbation
- difficult with glasses
- corneal transplantation has high degree of success
- exacerbated by eye rubbing; should be discouraged
Corneal Dystrophies
- heterogenous condition
- Fuchs Endothelial Dystrophy
Fuchs Endothelial Dystrophy: early and late
- early: enothelial cells produce guttata (raised wart like growths)
- late: endothelial cells die
Fuchs endothelial dystrophy: cause
- loss of endothelial cells, which results in edema and bullous keratopathy (stomal swelling)
Vitamin A deficiency leads to what disease
- Xeropthalmia
Metabolic Diseases
- heterogenous
- hunter’s and hurler’s syndrome
Metabolic diseases: disease process
- deposition of compounds in various parts of the body where they should not be
- may affect cornea, retina, and/or optic nerve
Metabolic diseases: treatment
- corneal transplant is an option, but many diseases affect retina and optic nerve as well, which would not help visual outcomes
- hematopoietic stem cell transplants may help improve corneal clearity
Treatment for corneal damage and disease
- eye drops & topical lubricating ointments: problem with compliance
- amniotic membrane transplant
- corneal transplant
- artificail corneal-boston keratoprosthesis (KPro): will develop glaucoma, risk of retinal detachment
Cataract: disease process, causes, treatment
- loss in lens transparency
- causes: congenital or acquired-drugs(corticosteroids), genetic, infections of mother during pregnancy, biochemical disorders
- early treatment important for children with congenital cataract, outcomes are typically good
Glaucoma: basics
- visual field loss from peripheral to central
- most due to high IOP but normal & low tension glaucoma exist
- can be open-angle or closed angle and primary or secondary
Importance of IOP in glaucoma
- high IOP is a risk factor for glaucoma, not guaranteed to get it if you have IOP
Primary open angle glaucoma
- iridocorneal angle is open; few changes is trabecular meshwork
- most genes unknown
Secondary open angle glaucoma
- angle is open but is occluded
- example: pseudoexfoliation glaucoma - pigment from iris breaks off and blocks the angle
Primary angle closure glaucoma
- angle is closed, reducing aqueous humor outflow
- iris pushes forward angle narrows or closes
- typically found in hyperopic individuals w/ shallow anterior chambers
Secondary angle closure glaucoma
- results from pathologies that draw iris over trabecular meshwork
- medical emergency**
Treatments for glaucoma
- nothing new since the 80s
- only approved treatments rely on reduction of IOP
- eye drops: many different types & can be combined
- sugery
Treatments for glaucoma: eye drops
- beta blockers: decrease amount of aqueous humor produced
- prostaglandin analogs: increase the outflow from the eye
- carbonic anhydrase inhibitors: decrease production of intraocular fluid
- alpha agonists: decrease production and increase drainage of fluid
Treatments for glaucoma: surgery
- laser trabeuloplasty: increases drainage of the angle in POAG
- iridotomy: laser treatment for narrow angle glaucoma that creates tiny holes in the iris
- operative shunt: creates bypass drainage channel to lower eye pressure
Age related macular degeneration: result, forms
- results in damage to macula
- occurs in dry or wet form
- dry: characterized by drusen deposits in Bruch membrane
- wet: neoangiogenesis (absent in dry form)
Treatment for dry AMD
- NO TREATMENT
Treatment for wet AMD
- injection of VEGF antagonists into vitreous every 3 months
- risk is needle being put into retina every 3 months
Diabetic retinopathy: types
- non proliferative & proliferative
Diabetic neuropathy: cause
- result of damaged blood vessels
Non-proliferative DR: why non proliferative & abnormalities seen
- non proliferative b/c eye doesn’t make new blood vessels during eary stage of disease
- microaneurysms, breakdown of blood retinal barrier, macular edema
Non proliferative DR: exudate location
- exudates occur in outer plexiform layer
- may have micro occlusions
Proliferative DR
- characterized by neovascularization of optic nerve head or retina
- may have hemorrhage; vitreous detachment
Retinal detachment: disease process & types
- separation of neural retina from retinal pigment epithelium
- non rhegmatogenous: without a break in retina-vitreous border
- rhegmatogenous: with a break of retina-vitreous border
Retinal detachment: causes & treatment
- causes: typically associated with trauma
- treatment: laserpexy or cryopexy to reattach retina + virectomy + gas to press retina to the globe
- outcomes are typically good
Retinitis pigmentosa: cause, affect, treatment
- inherited condition, 1/3600 incidence
- affects rods, cones, and or RPE
- affects peripheral vision first and early night blindness
- NO treatments
Retinal artery occlusion
- sudden unilateral visual loss
- results in diffuse infarct of retina
- PALLOW OPTIC DISK AND CHERRY RED FOVEA
- varied treatments to reduce occlusion
Retinal vein occlusion
- sudden unilateral vision loss
- results in diffuse infarct of retina
- OPTIC DISK SWELLING, RETINAL HEMORRHAGE AND DIALTED VEINS
Compressive optic neuropathy: cause, associated with, treatment
- results from pressure on the optic nerve in orbit
- associated with Grave’s disease or neoplasm affecting orbit
- treatments: removal of neoplasm, orbital decompression, CORTICOSTEROIDS
Optic neuritis: key feature
- orbital or ocular pain when moving eyes
Optic neuritis: process
- loss of vision secondary to demyelination and inflammation of optic nerve
Optic neuritis: result, cause, treatment
- results in scotoma of visual field
- cause: MULTIPLE SCLEROSIS, infection, autoimmune, drug induced
- treatment: corticosteroids does NOT show long term benefit
Anterior ischemia optic neuropathy: types
- non arteritic
- arteritic
Anterior ischemia optic neuropathy: non arteritic cause
- results from CV risk factors in patients w/ crowded optic disks
- most cases are idiopathic
Non arteritic AION: disease process
- isolated white matter stoke in optic nerve
- sudden unilateral visual loss
- optic disk edema
- MORE COMMON
Non arteritic AION: treatment
- high dose corticosteroids may be useful, no consensus
Arteritic AION: cause
- due to temporal arteritis
- inflammation of medium sized blood vessels
- occurs with advancing age
Arteritic AION: result and treatment
- results in complete vision loss in one eye, followed by other eye if left untreated
- treatment: long course of corticosteroids
Posterior ischemia neuropathy: when is ti diagnosed
- disease of occlusion
- rule out all other disease then say it’s this
Posterior ischemia optic neuropathy: affect, cause
- affects retrobulbar portion of optic nerve
- occurs in patients with HTN, diabetes, smokers
- can occur as complication of spinal surgery
- due to decreased blood flow, leading to death of optic nerve cells
Posterior ischemia optic neuropathy: disease process
- death of optic nerve cells causes inflammation, which compresses optic nerve in the optic canal
