Definitions Flashcards
ATR - against the rule
flatter in the vertical; steeper in horizontal (180); young and old
WTR - w/ the rule
steeper in the vertical; flatter in the horizontal; normal age population
amyloids
misfolded proteins
scleroderma
hardening of the dermis
posterior embryotoxon
Posterior embryotoxon presents as a thin, greyish-white, arcuate shaped ridge that runs adjacent to and parallels the limbus at the inner surface of the cornea. Axenfeld-Rieger anomaly occurs in association w/ posterior embryotoxon. http://www.ijo.in/articles/2011/59/4/images/IndianJOphthalmol_2011_59_4_312_82003_f1.jpg
anterior synechia
abnormal adherence of iris to corneal endothelium.
posterior synechiae
abnormal adherence of anterior surface of lens to iris
persistent pupillary membranes
remnant of the fetal iris membrane presenting as thin strands crossing the pupil
What does the QRS complex represent?
depolarization of left and right ventricles
What does the T wave represent?
ventricular repolarization, relaxation of the ventricles
index of refraction (n) of crown glass
1.52
Side walls of cells (epithelium/NPEC) are connected by ___________.
desmosomes
Which structures of the brain are a part of the limbic system and is involved in emotions?
amygdala, hippocampus, regions of the septal area, and limbal cortex
What is included in the limbal cortex?
hypothalamus, the cingulate gyrus, and the fornix
Where do the optic tracts of the eye terminate?
lateral geniculate nuclei (LGN) located in the thalamus
Where does information pass after the LGN?
primary visual cortex
Pulmonary vein-> left atrium-> mitral valve-> left ventricle-> semilunar valves-> aorta
Oxygenated blood is transported via the pulmonary veins to the left atrium. Blood then passes through the mitral valve to the left ventricle. Upon contraction of the left ventricle, blood is pushed through the left semilunar valve to the aorta where it then travels through arteries, arterioles, and capillaries for distribution throughout the body.
Excessive pantotilt causes…
increased (+/-) sphere power and induced cylinder axis 180 of the same power (+/-) as the sphere. A plus sphere will mean a (+) cyl is induced!
When you have a +2º pantoscopic tilt you have a ________ change in height.
-1mm height; also by increasing tilt, you are increases the field of view through the reading add
-2º pantoscopic tilt = _____ change in height.
+1mm height
horizontal prism w/ same base are _______
added together; i.e. BO + BO
vertical prisms w/ opposite bases are _______
added together; i.e. BU + BD; same side vertical prisms are subtracted from each other!
What is the ANSI prism tolerance?
Horizontal 2/3 PD (0.66PD); vertical 1/3 PD (0.33PD)
Your patient has an imbalance > 1.50 PD. You want to give him slab-off w/ a BU prism (correct tx), which lens do you place the slab off on?
The most minus lens because you are adding BU. You will always under prescribe the prism if needing to choose. The lower cost and quicker processing option is a reverse slab off, which you would place on the least minus lens(?)
What kind of lens does a Fresnel prism simulate?
reverse slab off lens
Define aniseikonia
A relative difference in size and/or shape of the ocular images. Pt will experience asthenopia, headaches, photophobia
Axial ametropia.. fit w/ ______
spectacles
Refractive ametropia (Ks are different)… fit w/ ______.
contact lenses
Flatten/Steepening by 1.00 means +/- 1.00D from the BC
i.e. 45.25D that is too steep by 1.00D. Flatten by 1.00 –> 44.25D, FAP, creates a minus tear film, so you have to add PLUS to the Rx (changing -3.75 to -2.75D)
prostaglandins decrease IOP by _________.
Increase uveoscleral outflow. decrease IOP by 33% on average (20-40%).
Which topical IOP meds decrease aqueous secretion?
ABCs!!!!!
alpha-agonists (apraclonidine, brimonidine)
beta-blockers (timolol)
carbonic anhydrase inhibitors (dorzolamide)
define cicatricial
scar/scarring related
Stocker line
deposition of iron, corneal epithelium, at the leading edge of pterygium
Hudson-Stahli line
iron, middle and lower third of cornea
Fleischer ring
iron, base of cone in keratoconus
What is the average size diameter of the iris?
12mm; iris is an extension of the anterior portion of pars plicata, the transition junction is the “root of the iris” and is the thinnest portion of the iris (0.5mm thick).
Which frames should not be heated?
polyamide, copolyamide, carbon fiber, carbon fiber graphite, or polycarbonate
conditions that falsely elevated A1c levels (5)
iron deficiency anemia
Any process that slows erythropoiesis increases A1c by maintaining an older erythrocyte cohort in the blood plasma (i.e. aplastic anemia).
alcoholism
hyperbilirubinemia
certain medications (high doses of salicylate, chronic opioid use)
False lower A1c levels: (6 conditions)
Any process that shortens the linespace of erythrocytes (i.e. hemolytic anemia, chronic kidney or liver disease).
Vitamins C and E (by inhibiting glycosylation of glucose to hemoglobin).
Pregnancy
Splenomegaly
Rheumatoid arthritis
Certain medications (antiretrovirals, ribavirin, and dapsone)
Systolic pressure resulting primarily from contraction of which chamber of the heart?
the left ventricle
When is diastole pressure occurring?
As the heart relaxes and blood flows out of the aorta (lowest measure of blood pressure exerted on the vessel walls)
How do prokaryotic cells create new genomes/reproduce?
transformation (uptake of naked DNA), transduction (transfer DNA from bacterium to another via virus), and conjugation (btwn donor w/ plasmid and recipient bacteria; donor imitates w/ a sex pilus).
Equation for finding minimum anti-refractive coating thickness.
Thickness = wavelength / (4 x index of coating)
Equation for PD caused by light deviation
P = (100) (x/d); P = PD, x = total distance light is deviated (cm), d = total distance from prism to location where deviation is measured (cm)
spatial summation (scotopic system, rods) means _______ sensitivity and ______ resolution.
higher sensitivity and poorer resolution
Because a lot of information is gathered by the rods and given to one ganglion cell, the resolution is poor.
ANSI standard for sphere powers.
For sphere powers =/
ANSI standard for cylinder power.
Cylinder power 2.00D or less +/- 0.13D.
Kearns-Sayre syndrome triad
i. Progressive external ophthalmoplegia (CPEO), salt and pepper pigmented retinopathy, 1 or more systemic complications (heart block, cerebellar ataxia, abnormally elevated CSF protein).
prosencephalon (forebrain) becomes
telencephalon and diencephalon
Telencephalon becomes cerebrum (cerebral cortex, white matter and basal ganglia).
Diencephalon forms 4 distinct components including thalamus, subthalamus, hypothalamus, and epithalamus.
mesencephalon (midbrain) is located…..
Mesencephalon located below the cerebral cortex (telencephalon) and above hindbrain, does not differentiate any further.
Rhombencephalon (hindbrain), the third ventricle during early development, becomes…
myelecephalon and metencephalon
Myelencephalon forms medulla oblongata.
Metencephalon forms pons and cerebellum.
residual volume definition
volume of air remaining in the lungs after a maximal exhalation
expiratory reserve volume definition
maximal volume of air that can be exhaled at the end of a tidal exhalation
functional residual capacity
amount of air in the lungs following a tidal exhalation (expiratory reserve volume + residual volume)
vital capacity
maximal volume of air that can be exhaled after the deepest inhalation possible
total lung capacity
the total volume of lungs at maximal inhalation (vital capacity plus residual volume)
tidal volume
volume of air that is inhaled and exhaled during quiet breathing
telecanthus definition
describes increased distance between eyelids at the medial canthus
epicanthus
orbital fold or Mongolian fold of eyelid
EOG can detect what? And what’s a good arden ratio?
best’s disease (decreased arden ratio 1.80
Different waves of the ERG (ABC)
A: photoreceptors
B: bipolar/Muller
C: RPE
what does VEP detect?
MS, will be less than the normal 100msec response
What are the three things that make up the blood-aqueous barrier?
- endothelium of schlemm’s canal
- iris vessels
- non pigmented ciliary epithelium
**All have tight junctions.
What happens after a corneal abrasion?
- basal cell mitosis stops
- cells around defect lose attachment to BM and enlarge/migrate to create an epithelial sheet
- Hemidesmosomes created to allow proper adhesion between migrated cells and the BM
- basal cell mitosis occurs at a rapid rate
- wing cells do not undergo mitosis, only basal cells do
Anterior lens epithelium differentiation and formation…
anterior lens epithelium –> secondary lens fibers –> fetal nucleus
posterior lens epithelium transforms/produces…
posterior lens epithelium –> primary lens cells –> embryonic lens nucleus
Which blepharitis is this:
- greasy lid margins
- lashes that stick together (teepee lashes)
- scales are soft and may be seen anywhere along the eyelashes and lid margins
seborrheic blepharitis
Which blepharitis is this?
- hard scales at the base of the lashes (ccllarettes)
- erythema and telangiectasia of the lid margin
staphylococcal blepharitis
Define chalazion.
sterile, accumulation of lipogranulomatous material caused by blocked meibomian gland orifices
Where is thymosin found? and what does it do?
found in Thymus, a hormone essential for T-cell maturation
- majority of upper eyelid
- temporal aspect of lower lid
- conjunctival vessels
all drain into which lymph nodes?
preauricular (parotid) lymph nodes; located below the base of the mandible
- 1/3 of nasal aspect of upper lid
- medial 2/3rds of the lower lid
- nasal portion of the conjunctival vessels
all drain into which lymph node?
submandibular nodes; located below the base of the mandible
Dx for a patient who is +Sx for:
- lacrimation
- photophobia
- decreased vision
- red eye
- severe pain that is highly out of proportion to the ocular signs
- likes to go in hot tub w/ contact lenses on
And how would you treat it?
acanthamoeba keratitis
Tx: chlorhexidine gluconate 0.02% q1h or polyhexamethylene biguanide (PHMB) 0.02% q1h for 72-96 hrs; then taper to q2h for 2-4 weeks, then taper again to aid for 6-12 months. Use along w/ neosporin® (polymyxin B + bacitracin + neomycin) q1h and/or Brolene® (dibropropamidine isethionate) q1h. Also w/ oran antifungals (–azole)
most common cause of episcleritis
idiopathic; other causes include gout, Herpes zoster, Crohn’s disease, syphilis, Lyme disease, SLE, and RA
define snow-banking
Seen in in pt w/ intermediate uveitis where inflammatory cells can be observed lying over the inferior pars plana.
etiology of the aqueous fluid appearing hazy/cloudy (flare, smoke in a dark room) in the anterior chamber
flare = increased protein in aqueous fluid and is seen in associated w/ cell (d/t breakdown of blood-aqueous barrier as a result of trauma, infection, inflammation due to uveitis, scleritis, keratitis, or ocular surgery).
Cells will appear as small white particles floating in the anterior chamber.
Define non-granulomatous KPs
neutrophils + lymphocytes and clinically resembles small, discrete, fleck-like, linear, or stellate corneal endothelial opacities.
Define Mutton-Fat KPs
granulomatous involvement, epithelioid cells + macrophages, larger, thicker, fluffy, greasy or waxy look; fewer in number 10-15.
define red KPs
when RBCs are present in the anterior chamber in addition to inflammatory cells (hemorrhagic uveitis)
What is the normal blood plasma level of bilirubin?
should be below 1.2 mg/dL
corneal collagen cross-linking is a surgical procedure that involves what?
UV-A light + B2 (riboflavin)
Where are Vogt’s striae found and which diseases?
- fine vertical lines deep w/in stroma
- disappear w/ external pressure
- present most commonly in keratoconus, but also w/ PMD
ophthalmia neonatorum secondary to Neisseria gonorrhoeae presentation
- development w/in 2-6 days postpartum
- hyper acute conjunctivitis
- bilateral
- periorbital edema, conjunctival chemises
- +++ purulent discharge
ophthalmia neonatorum d/t chlamydia trachomatis
- mild/moderate symptoms of unilateral/bilateral conjunctivitis
- presentation 5-14 days after birth
- most common cause of ophthalmia neonatorum
- lid edema, conjunctival chemises, punctate corneal opacities, occasionally micropannus formation
average imbibition pressure (IP) of the corneal stroma
- 40mmHg
if the cornea is steeper horizontally (180º) then the image is ____________ in this meridian.
Steeper = minified;
Flatter = magnified
Which layer does a corneal arcus affect?
white/yellow circular band of cholesterol deposits in the stromal periphery
Organism most commonly associated w/ formation of a true membrane in cases of acute membranous conjunctivitis
Corynebacterium diphtheria infection.
Other organisms (Strep, N. gonorrhoeae, S. aureus, H. aegypticus, E. coli, adenoviruses, and herpes simplex) can all cause it, but the true membrane is synonymous w/ diphtheric conjunctivitis.
which refractive surgery is indicated for patients with recurrent corneal erosions?
PRK, photo refractive keratectomy
photo therapeutic keratectomy (PTK) has been shown to be useful in treating RCE, so might as well at a benefit of correcting patient’s refractive error
What occurs during accommodation?
- IOP decreases momentarily
- equatorial circumference of lens decreases (lens becomes more spherical)
- anterior surface of lens moves forward
- posterior surface remains stationary
- decrease anterior chamber depth
Which wavelength of light will scatter more w/ water vacuoles in the crystalline lens?
short wavelengths scatter more from small particle scatter (i.e. water vacuoles), so blue light may be more visually disturbing
Which histamine receptors plays a primary role in ocular allergies?
histamine binds to H1 receptors on nerves (causing itching) and blood vessels (causes chemises and erythema)
most frequent cause of contact lens-associated keratitis
pseudomonas aeruginosa
ANSI axis deviation for cyl 0.25D
14º
ANSI axis deviation for 0.50D cylinder
7º
ANSI axis deviation for 0.75D cylinder
5º
ANSI axis deviation for 1.00D, 1.25D, 1.50D cylinder
3º
ANSI for > 1.75D cylinder
2º
Advantages of Glass (and a huge disadvantage)
Advantages:
- high index of refraction = thinner lenses
- high Abbe number = less chromatic aberration
- glass blocks UV light
- very resistant to scratching
Disadvantages:
- high specific gravity
Volume, weight, and occupation of vitreous in eye.
4mL, 4.0grams, 2/3 bulk of eye
where are muller cell bodies found in the retina?
INL, inner nuclear layer
Information from the left visual field of Right eye ultimately ends up processed where?
The right dorsal LGN (lateral geniculate nucleus).
Which species can invade an intact cornea?
Neisseria (gonorrhoeae)
define contact dermatitis
- scaly, rough skin
- can be swollen, but w/o discharge or swollen pre-auricular nodes
- type 4 allergic reaction
define EKC (epidemic keratoconjunctivitis)
- tender pre-auricular nodes
- viral origin
- rarely see copious discharge, generally watery discharge
3 signs commonly associated w/ 3rd nerve cranial nerve palsy
- intorsion of the eye, which increases in attempted downsize
- limited depression of the involved eye
- normal abduction of the involved eye
Which muscles would a 3rd nerve palsy affect?
- SR, IR, MR, and IO
- levator
- pupil sphincter
- accommodative fibers
What does Avelino dystrophy (granular dystrophy type 2) affect?
histological changes consistent w/ abnormal deposition of amyloid and hyaloid in the stroma
Where does granular dystrophy type 1 affect?
abnormal amorphous hyaline deposits only in the corneal stroma
Where does macular dystrophy affect?
abnormal aggregations of GAGs as well as unusually close packing of collagen fibrils in the corneal lamellae
Anticonvulsant drug phenytoin (Dilantin®) can lead to which ocular side effect?
- nystagmus
- ophthalmoplegia
- mydriasis
- miosis
- diplopia
Weber’s test is used for what?
to distinguish between conductive or sensorineural hearing loss
Eustachian tube
also known as the auditory tube or pharyngotympanic tube, is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. In adult humans the Eustachian tube is approximately 35 mm long and 3 mm in diameter.
Define albumin
predominant protein in plasma, which makes up 50-60% of the total blood volume
what is plasma made of?
50-60% of total blood volume, made up of:
- water (90%)
- proteins
- dissolved gases
What is the cellular component of blood comprised of?
40-50% total blood volume.
- white blood cells
- platelets (second largest constituent)
- RBCs (bulk of cellular portion)
define agglutination
clumping of the blood, can lead to blockage of blood vessels causing tissue damage and/or death
Dx diabetes via Hemoglobin A1c
6.5%
Dx diabetes via fasting plasma glucose
> 126 mg/dL
Dx diabetes via 2 hour plasma glucose
> 200 mg/dL
Why is metformin such a great tx of choice for diabetes?
- only drug that prevents cardiovascular complications
- drug w/ least adverse effects and lower risk of hypoglycemia
- generally used for DM type 2
strategy for correction of SA (spherical aberration) and coma
- Best-form lenses
- aspheric lenses
- small stop
- lens systems (doublet)
Strategies for correcting oblique astigmatism (OA)
- Tscherning’s ellipse (Ostwald, Wollaston)
- Corrected curve lenses = point-focal form
Strategies for correcting curvature of field (CoF), as seen via movie screens.
- Tscherning’s ellipse (Ostwald, Wollaston)
- corrected curve lenses = Percival form
So, know that tscherning’s ellipse can correct for oblique astigmatism and curvature of field.
When does oblique astigmatism occur?
occurs w/ monochromatic aberrations, pantoscopic tilt, and faceform tilt
This is only relevant in higher power lenses.
A minus lens tilted along a meridian induces ______ sphere power and _____ cylinder with its axis along the tilt meridian.
minus, minus
A plus lens tilted along a meridian induces _____ sphere power and _____ cylinder with its axis along the tilt meridian.
plus, plus
equation for chromatic aberration (LCA and TCA)
LCA = F/v
TCA = P/v