Glaucoma Flashcards
What happens when light hits the retina
photoreceptors turn the light into electrical signals
What does the top number on the snelling chart refer to
the distance in feet you stand to the chart
What does the bottom number on the snelling chart refer to
the distance in which a person with normal eyesight can read the same line
What type of equipment is used for refractive testing
phoropter
What equipment is used for glaucoma evaluation
gonioscopy
What is the normal eye pressure range
10-21 mmHg
What is the leading cause of blindness / low vision in the US due to
aging
What are some age related vision changes
cataracts
diabetic retinopathy
glaucoma
macular degeneration
What is the most frequent eye problem in the US
Refractive errors
What are refractive errors
myopia
hyperopia
astigmatism
presbyopia
What is near sightedness known as
myopia
What is farsightedness
hyperopia
What causes distorted vision at all distances
astigmatism
What is the loss of ability to focus up close and when does it generally occur
presbyopia
40-50y/o
What is the cause of myopia
cornea is too steeply curved
axial eye length too long
*point of focus is in front of retina
How do you correct myopia
concave lens
What causes hyperopia
cornea too flat
axial length too short
*point of focus is behind retina
How do you correct hyperopia
convex lens
What causes astigmatism
variable curve of the cornea / lens causing light to focus at different points
hat type of lens is used to correct astigmatism
cylindrical lens
What causes presbyopia
loss of the lens’ ability to change shape to focus on near objects from aging
What is anisometropia
Significant difference between refractive errors of the 2 eyes
*>3 diopters
What is aniseikonia
Different image sizes
What are common s/sx of refractive errors in patients
blurred vision
headaches
perceived imbalance
Ocular surface desiccation
What do refractive errors cause headaches
excessive colliery muscle tone
Prolonged squinting/frowning
What are the signs of ocular surface desiccation from excessive staring
eye irritation
itching
visual fatigue
foreign body sensation
redness
What are symptoms of refractive errors in children
frowning / squinting when reading
excessive blinking
rubbing of eyes
How do you workup refractive errors
visual acuity testing
refraction
comprehensive eye exam
How often should visual acuity and refraction testing be done
every 1-2 years
Who preforms comprehensive eye exams
ophthalmologists
optometrist
How can you treat refractive errors
glasses
contacts
surgery
What are the three numbers that are included with corrective lens prescriptions
spherical correction
cylindrical correction
axis
What is the power of spherical corrections used for
- (myopia)
+ (Hyperopia)
What is amblyopia
lazy eye
When can severe loss of vision occur with amblyopia
if the affected eye is not detected and treated before 8 years old
What occurs amblyopia
visual cortex suppress image from affected eye
if suppression persists long enough - vision loss can be permanent
What is strabismus
misalignment of the eye resulting in different retinal images being sent to visual cortex
What is anisometropia
different focus of retinal images with image from eye with greater refractive error being less well focused
What causes obstruction of the visual axis
some point between surface of eye and retina, something interferes with or completely prevents formation of retinal image of affected eye
How can strabismus be confirmed
with alternate cover test or cover to uncover test
How can anisometropia be confirmed
refraction of each eye
How can obstruction of visual axis be confirmed
ophthalmoscope or sit-lamp exam
How do you treat amblyopia
glasses / contacts
patching (Common in kids)
Atropine drops
tx of strabismus if present
What is the most common cause of IRREVERSIBLE central vision loss in older patients
AMD (macular degeneration)
What is the diagnostic test for AMD
Dilated fundoycopic findings
What tests can be done for AMD
Color photographs
fluorescein angiography
optical coherence tomography
How do you treat AMD
Dietary supplements
intra-vitreal injection
laser photocoagulation
low vision devices
photodynamic therapy
What are the different forms of AMD
Dry (all AMD starts here)
Wet
What does dry AMD do to the eye
Change in retinal pigment epithelium (dark pinpoint areas)
What occurs in the eye with dry AMD
Accumulation of waste products from rods and cones (drusen) will look like yellow spots
What causes dry AMD to turn wet
New abnormal blood vessels develop under the retina (choroidal neovascularization)
What is physically different with wet AMD compared to dry
Localized macular edema or hemorrhage may elevate an area of the macula or cause pigment epithelial detachment
What does untreated neovascularization cause
disciform scar under the macula
What is the clinical presentation of dry AMD
Loss of central vision that occurs over years and is generally painless
central blind spots (scotomas)
usually bilateral
Fundoscopic changes
What fundoycopic changes occur with dry AMD
Drusen
changes in retinal pigment epithelium
chorio-retinal atrophy
What is the clinical presentation of wet AMD
Rapid vision loss usually over days to weeks
legally blind in affected eye if not treated
often unilateral
What is the first sx of wet AMD
visual distortion (scotoma or metaporphopsia)
What is metaporphopsia
Curving of straight lines
What are some fundoscopic changes with wet AMD
Subretinal fluid (elevation)
Retinal edema
gray-green discoloration
exudates in/around macula
sub retinal hemorrhage
detachment of retinal epithelium
What test is better for wet AMD
color fundus photography
fluorescein angiography
What is optical coherence tomography help identify
Aids in identifying intraretinal / sub retinal fluid
assess response to treatment
What does Amsler grid help detect
visual changes
What supplements can help manage dry AMD
Zinc
Copper
Vitamin C/E
Lutein
What can help manage wet AMD
VEGF infections
thermal laser photocoagulation
Photodynamic therapy
injected corticosteroids
What supportive measures can be used for patient with lost central vision (AMD)
Low vision devices
large print on electronics
low vision counseling
if someone feels like they are looking through a steamed up window.. what do they most likely have
cataracts
What is the leading cause of blindness and vision loss in the US
Cataracts
Is cataracts age related
No, can be congenital or degenerative
Where in the eye can cataracts occur
central lens nucleus (nuclear)
beneath posterior lens capsule
On side of the lens (Cortical)
Which form of cataracts does not interfere with central vision
cortical
What are main symptoms of cataracts
painless vision blurring
gradual
How do you diagnose cataracts
ophthalmoscope and slit-lamp exam
How do you treat cataracts
surgical removal and placement of intraocular lens
What are early symptoms of cataracts
loss of contrast, glare, needing more light to see well, problems distinguishing dark blue from black
What are rare symptoms that can occur with cataracts
swelling pushing iris over trabecular drainage meshwork, causing occlusion and secondary closed angle glaucoma
What is nuclear cataract
Distance vision worsens, near vision may improve in early stages temporarily
presbyopic patients may be able to temporarily read without glasses (second sight)
What is posterior sub scapular cataracts
Reduced visual acuity when the pupil constricts
more likely to cause loss of contrast and glare
disproportionally affects vision because opacity is located at crossing point of incoming light rays
How do you workup cataracts
ophthalmoscope followed by slit-lamp
*best with pupils dilated
Exam of red reflex through dilated pupil (30cm away)
What will cataracts look like
gray/white/yellow-brown opacities in lens
What test is definitive for cataracts
slit-lamp because it provides more detail about character, location, and extent of opacity
How do you treat cataracts
frequent refractions and corrective lens prescription changes
long term pupillary dilation for small centrally located cataracts
Indirect lights while reading to minimize pupillary constriction
What are the indications for surgery with cataracts
best vision obtained with glasses is worse that 20/40
bothersome halos or starburst
vision is limiting
What are the different types of cataracts surgery
intracapsular
extracapsular
phacoemulsification
What is intracapsular cataract extraction
cataract and lens are used in one piece
What is extra capsular cataract extraction
hard central nucleus is removed in one piece and then soft cortex is removed in multiple pieces
What is phacoemulsification
Type of extracapusular
**Gold standard cataract surgery
What do patients have to avoid for several weeks after cataracts surgery
valsalva maneuver
heavy lifting
excessive forward bending
eye rubbing
What is the second most common cause of blindness worldwide
Glaucoma
What is the leading cause of blindness for hispanics and African Americans in the US
glaucoma
What is the most common type of glaucoma in the US
primary open angle glaucoma
What causes glaucoma
progressive optic nerve damage with a relative increase in IOP
What is glaucoma
acquired loss of retinal ganglion cells and axons within the optic nerve that results in a characteristic optic nerve head appearance and peripheral vision loss
What occurs with open angle glaucoma
> 98% of aqueous humor exits the eye via either trabecular meshwork and canal of schlemm
What are the divisions of glaucoma
primary (cause of outflow resistance or angle closure is unknown)
Secondary (outflow resistance results from a known disorder
What are symptoms of closed angle glaucoma
severe ocular pain and redness decreased vision
colored halos around lights
H/A
N/V
Increased IOP
What is definitive treatment of closed angle glaucoma
iridotomy
What are risk factors for closed angle glaucoma
Fhx
advanced age
ethnicity (asians at most risk)
What type of glaucoma is an ophthalmic emergency
primary acute closed angle
what IOP is indicative of closed angle glaucoma
> 40mmHg
What is intermittent closed angle glaucoma
an episode of pupillary block that resolves spontaneously after several hours -> generally after sleeping supine
What is chronic closed angle glaucoma
angle narrows slowly, which allows for scarring between peripheral iris and trabecular meshwork
IOP elevation is slow
What can cause secondary closed angle glaucoma
proliferative diabetic retinopathy
ischemic central vein occlusion
uveitis epithelial down-growth
Why is acute closed angle glaucoma misdiagnosed
systemic complaints being so severe
What will be seen on exam with acute closed angle glaucoma
conjunctive hyperemia
hazy cornea
fixed mid-dilated pupil
anterior chamber inflammation
IOP 40-80
What is seen on exam with chronic closed angle glaucoma
gonioscopy showing peripheral anterior synechiae
optic nerve/visual field abnormalities
How do you treat acute closed angle glaucoma
Timolol
pilocarpine
Brinonidine
Acetazolamide
osmotic agent
What is definitely treatment of acute closed angle glaucoma
laser peripheral iridotomy
*done as soon as cornea is clear and inflammation has subsided
What are risk factors for open angle glaucoma
older age
positive family history
African Ethnicity
Hypertension
Diabetes
Myopia
What is occurring with open angle glaucoma
aqueous humor drainage is inadequate but production by ciliary body is normal
What is found on physical exam with open angle glaucoma in asians
IOP with average range but optic nerve damage and visual field loss typical of glaucoma are present
*Have higher risk of intravascular disease
How will the optic nerve look with open angle glaucoma
increased cup to disc ration
pitting / notching of rim
splinter hemorrhage
vertical cup elongation
bayoneting
What is bayoneting in the eye
quick angulations in course of exiting blood vessels
What is diagnostic of glaucoma regardless of IOP
thinning of neurosensory rim
Visual field change
What is the clinical presentation of open angle glaucoma
Visual field defects
arcuate scotoma extending nasally
temporal wedge defect
paracentral scotoma
What is the initial treatment for open angle glaucoma
drug therapy
then laser and last option is surgery
Which medications can be used to manage open angle glaucoma
prostaglandin analogs
beta blockers (timolol)
