Test 1 Flashcards
Which of the following columns in the OD histogram is driven equally by input from the right and left eyes? What about the other columns
1- Contra eye 2-Both, but not equal 3- Both, but not equal 4- Equal input 5- both but not equal 6- both but not equal 7- ipsi
Co2 can be transported from tissues to the lungs through which methods
Bicarb 95%
Bound to hemoglobin as carbaminohemoglobin 5%
dissolved in blood plasma 5%
Most common cause of posterior uveitis
Toxoplasmosis
-Most often congenital via transplacental transmission. Could also be acquired by inhaling a parasite in cat feces or by eating undercooked meat.
Medication prescribed for Tb that is most likely to cause retrobulbar Optic neuritis
Ethambutol
Most often reversible, but may take months.
image jump is based on what
Add power and distance from the top of the segment to the near OC
scotopic system
Greater sensitivity for visual stimuli (more spatial summation) but poor visual acuity due to larger pixels for spatial summation.
Spatial summation means that all visual input within a given space pixel is summed together by the visual cortex.
Thimerosal is the preservative in
Trifluridine
Which preservative is prescribed to chelate calcium in patients with band keratopathy
EDTA
Bucket 2 of pharm
Anti-cholinergic
1st gen antihisamines (PHEN)
Anti psychotics (Phenothiazine)
Antidepressants (TCA, MAOIs)
Slab off
Add base up to the more minus lens.
Most common site of metastases for a choroidal, conj, or iris melanoma
Liver
Which corneal stromal dystrophies are related to a mutation in the TGFB1 gene?
Granular, lattice, avellino
Min blank size formula
M = ED + 2d + 2mm
d= decentration per lens
Frame pd - pt pd / 2
VOR
Obtains image on the fovea during short head movements
Tritanopia
Missing cyanolabe
Protanopia
Missing erythrolabe
Deuteranopia
Missing chlorolabe pigment
There are no __ cones or rods within the central one degree of the foveola
Blue
Risk factors for bulls eye maculopathy
Treatment for 5+ years Liver disease Kidney disease 60+ years old High body fat Concomitant retinal disease Dosage 5+ mg/kg/day based on real body weight
Distortion
Different magnitudes of magnification for different object points away from the optical axis.
angle of anomaly equals what in HRC
Angle of anomaly = objective deviation
angle of anomaly equals what in unharmonious ARC
Greater than zero, but less than the objective deviation.
angle of anomaly equals what in paradoxical ARC
angle of anomaly is greater than the objective angle of deviation
3 examples of granulomatous inflammation
Sarcoid
TB
syphilis
Examples of extrinsic and intrinsic evaporative dry eye disease
Extrinsic- independent of lid pathology. Vitamin A deficiency, preservatives, CL wear.
Intrinsic- due to lid pathology. MGD, proptosis, decreased blink rate.
Which drug can cause secondary angle closure by causing choroidal swelling
Topiramate/Topamax
Moves iris forward –> angles narrows.
Type of herpes simplex stromal keratitis with direct invasion of the virus into the K stroma?
What is IK, disci form, and dendritic
Necrotizing- rare. Severe inflammation and necrosis –> thinning and perforation.;
IK is due to an antigen-antibody complement cascade against a virus or viral antigen.
Disciform keratitis is due to an immune response in the K endothelial cells. Poor pumping –> edema
Dendritic is most common
Molluscum contagiosa
- What is it
- Demographics
DNA pox virus
Single or multiple waxy nodules, umbilicate.
Immunocomp (HIV) or children
Latent nystagmus
Pathological nystagmus when one eye is occluded. Associated with essential infantile esotropia and amblyopia.
Accommodation reaches adult levels by
3 months
accommodation reaches adult levels when
3 months
Abbe values of Crown glass, CR39, polycarbonate, trivex.
What does abbe value mean?
Want a high abbe value= less chromatic aberrations.
58
58
poly 30
trivex 44
Define entrance pupil, exit pupil, aperture stop, field stop.
Entrance pupil- Image of the aperture stop formed by all the lenses in FRONT of it.
Exit pupil- the image of the aperture stop formed by all the lenses BEHIND it.
Aperture stop- physical entity that limits the amount of LIGHT entering the system
Field stop- physical entity that limits the SIZE of the object that can be viewed by the system.
Which vitamins can lead to toxicity
Fat soluble vitamins stored in the body
ADEK
Which water soluble vitamin aids in the synthesis of purine and pyrimidines
Folic acid
Deficiency causes impaired DNA and spina bifida.
What parts of visual pathway does the anterior choroidal supply
Optic tract, LGN, optic radiations.
Which 2 arteries supply the primary visual cortex
Posterior cerebral, middle cerebral.
What does each of the follow color vision tests detect
- Ishihara
- Nagel anomaloscope
- D 15
- HRR
- Ishihara: red green
- Nagel anomaloscope: Can distinguish between anomalous trichromat and dichromat.
- D 15: red green and blue yellow
- HRR: red green and blue yellow
Which 5 drugs can cause Whorl keratopathy
Amiodarone Indomethacin Hydroxychloroquin Chloroquine Tamoxifen
Is silicone more or less permeable to oxygen than water
More.
Which is why increasing water content in siHy lenses causes decreased oxygen transmission.
Average amp of accommodation formula
18.5 - 1/3(age)
Which molecule is found at 40x higher concentration in the vitreous compared to the blood
Vitamin C
systemic diseases associated with KCN
T-DOME !!
Turner syndrome Down syndrome Osteogenesis imperfecta Marfan syndrome Ehlers-Danlos
Thickness of cornea in the center
Thickest and thinnest points of the choroid, sclera, and retina.
Choroid:
Thickest at posterior pole 0.2mm
Thinnest at ora serrata 0.1mm
Sclera:
Thickest at 1mm
Thinnest at 0.3mm at reti insertions
Retina:
Thickest in the papilomacular bundle: 0.23mm
Thinnest at fovea: 0.1mm
Cornea is 0.52-0.55mm
Parinaud oculoglandular sydrome
Eye problem similar to conjunctivitis.
Affects swollen lymph nodes and fever
What do these stand for:
VRDL
RPR
FTAA
VRDL: Venereal disease research laboratory
RPR: Rapid plasma reagent card test
FTAA: Fluorescent treponema antibody absorption
4 types of bacteria than can penetrate an intact cornea
Canadian national hockey team: Corynebacterium dipltheriae, Neisseria gonorrhoeae, haemophilus, listeria
What corneal finding is characteristic of EKC
serotype 8
symptoms 8 days after exposure
SEIs 8 days after that. No longer contagious.
4 ways to dx syphilis
FTA- ABS
MHA- TP
Dark field microscopy
Enzyme immunoassay
Internal hordeola is most commonly caused by
S. Aureus
Staph epidermis is the most common cause of
Acute postoperative endophthalmitis
Strep pneumonia may cause what 2 infections
Pediatric bacterial conjunctivitis
K ulcers
When an ophthalmic topical drug contacts the tear film, the pH of the tears alters the drug to which of the following
Non0Ionized.
The pH of the tears is 7.54. When drugs contact the tear film, the tears alter the drug into a non ionized form (hydrophobic) which promotes absorption across the hydrophobic corneal epi and endothelial.
Ionized/hydrophillic drugs are less likely to be absorbed.
What does each pathway do
Medial lemniscus
Tectospinal
Trigeminothalamic
Spinothalamic
Medial lemniscus- touch, pressure, vibration from the body.
Tectospinal- reflexive head movements in response to visual stimuli.
Trigeminothalamic- pain and temp from the face.
Spinothalamic- pain and temp from the body.
Define Sensitivity Specificity Positive predictive value Negative predictive value
Sensitivity- Ability of a test to detect a patient has the disease. Good to be sensitive.
Specificity- Ability of a test to detect a patient doesn’t have the disease.
Positive predictive value- Probability that the patient has the disease if the test is positive.
Negative predictive value- Probability that the patient doesn’t have the disease if the test is negative.
What are these lasers used for: Argon Excimer Nd: YAG Helium neon
Argon- PRP, focal laser tx for ME
Excimer- LASIK, PRK
Nd: YAG- PCO, SLT, LPIs
Helium neon- illuminate the retina to view the fundus
How do photoreceptors collect photons/how does color vision work
A wavelength of a photon determines the probability that the photon is absorbed by a photoreceptor.
Based on the principle of univariance- once the photon is absorbed, all information regarding the wavelength of the photon is lost.
A single photoreceptor cannot discriminate color. Color vision is based on the relative responses of different photoreceptors based on the number of photons each absorbed.
