Random Pile of Done Flashcards
1
Q
Which type of glial cell lines the cavities of the CNS as well as the walls of the ventricles in the brain?
A
Ependymal Cells
NOTE: they also form the epithelium of the choroid plexus, which secretes CSF
2
Q
Which type of glial cells are considered non-neuronal cells of the CNS and serve to coat axons in a myelin sheath, which greatly increases the speed of conduction?
A
Oligodendrocytes NOTE: these cells also wrap numerous axons simultaneously, while Schwann cells insulate on a one-to-one ratio for cellular axons in the PNS
3
Q
Which glial cells are the most numerous and offer support and structure to the brain?
A
Astrocytes NOTE: these cells also play a large role in the formation of the BRB, which serves to inhibit toxic substances of the blood from entering the brain. These cells play an important part in removing NTs from synaptic zones as well as the removal of excessive etracellular potassium.
4
Q
Which type of glial cell are a type of macrophage that are called into action in the event of injury, disease or infection?
A
Microglia NOTE: these cells are capable of phagocytosis
5
Q
The primary absorption pathway for large, hydrophilic drugs is where?
A
Transconjunctival Route
6
Q
The primary absorption pathway for small, lipophilic drugs is where?
A
Transcorneal route
7
Q
Which 2 of the following ocular elements pass through the optic foramen before reaching the eye?
A
Opthalmic Artery and CN 2
8
Q
What is the average diurnal variation of IOP for a normal person who does not suffer from glaucoma?
A
3-5 mmHg NOTE: The average intraocular pressure (IOP) is around 15 mmHg (+/- 2.57 mmHg) for people without glaucoma or ocular hypertension. Pressures for most people also fall within 10.5-20.5 mmHg. IOP can fluctuate between 3-6 mmHg on a daily basis, most likely resulting from a change in aqueous production rather than aqueous drainage. A fluctuation of greater than 10mmHg is usually indicative of glaucoma.
9
Q
What is coat’s white ring?
A
A small, white, oval ring at the level of Bowman’s membrane that is associated with a previous corneal FB
10
Q
Which HA’s are most commonly caused by stress and may be attributed to poor posture, hunger, and fatigue?
A
Tension HA’s NOTE: this type of HA is associated w stiffness of the muscles in the neck region and pain around the occipital region or a vice-like pain in the frontal area. CC: “throbbing”
11
Q
Which HA’s are more commonly “associated acute” rather than “chronic nasal sinusitis” and usually present with a deep and constant pain in the frontal region of the head?
A
Sinus HA NOTE: pain in these cases is usually associated w/ other sinus symptoms such as rhinorrhea, feeling of fullness in the ears, fever, facial swelling, and lacrimation. CC: transient loss of smell. Majority will note an increase in pain/pressure when bending down
12
Q
Which thyroid hormone is released from the hypothalamus?
A
Thyrotropin-Releasing Hormone (TRH)
13
Q
Where is Thyroid Stimulating Hormone (TSH) produced?
A
Pituitary glands
14
Q
As demarcation lines, or high water marks, occur due to the proliferation of retinal pigment epithelial cells (3 months), what configuration do they make with respect to the ora serrata?
A
Convex NOTE: this represents sites of increased adhesion. With time, the demarcation line tends to lose its pigment and can be less obvious upon fundus examination
15
Q
What is or are the MOA(s) for Brimonidine (Alphagan) and Apraclonidine (Iopidine)?
A
- INC Uveoscleral outflow 2. DEC Aqueous production
16
Q
What are the 3 photopigments contained within the human cones?
A
Erythrolabe (565 nm), chlorolabe (535 nm), and cyanolabe (430 nm)
17
Q
What is the flow of aqueous out of the eye via trabecular outflow?
A
Uveal layer –> corneoscleral layer –> Juxtacanalicular layer –> Schlemm’s canal –> distal collector channels –> Aqueous veins –> Episcleral venous system
18
Q
For Keratometry, to extend the ranges down, what lens would you use and what range does it create?
A
-1.00 Lens Subtract 6D from the drum reading for flatter corneas
19
Q
What does adding a +1.25D lens to a keratometer do?
A
Add a range of 8-9D for steeper corneas
20
Q
According to the American Diabetes Association, asymptomatic pts who do not possess any RFs for DM should be screened at what age?
A
45 years old
21
Q
What is the reversible replacement of one differentiated cell type with another mature differentiated cell type (i.e. Barrett’s esophagus) known as?
A
Metaplasia NOTE: most common in epithelial tissues (can be from normal maturation or abnormal signaling). Original cells may not be robust enough to withstand harsh environments and thus change to a cell that is better suited
22
Q
What is this referring to: - Disorderly arrangement of cells due to an alteration of size, shape, and organization -Epithelial cells -Reversible* -Immature cells > Mature -Pap smears
A
Dysplasia
23
Q
What is an alteration of differentiation? -Poorly differentiated or undifferentiated -Divide rapidly but do NOT resemble normal cells structurally or functionally
A
Anaplasia (Ana is the weird kid, she is not differentiating the same as the other kids)
24
Q
What is protective against progression of diabetic retinopathy?
A
High Myopia NOTE: proliferation of DR can be triggered by traction of the retina caused by incomplete detachment of the vitreous –> fibrovascular tissue formation. Myopic pts w/ a PVD possess a DEC risk of traction & therefore a DEC risk of progression of DR.
25
What is the ideal clearance to be attained over the steepest region of the cornea when fitting a scleral CLs?
100-300 um
26
What is called when the ability to recognize faces is impaired while other aspects of visual processing remain intact?
Prosopagnosia
27
What is the condition in which patients cannot perceive motion but can acknowledge stationary objects without trouble?
Akinetopsia (AKA "motion blindness")
28
Which side of the temporal lobe maintains an image library of all faces one has remembered and recognizes?
Right
29
Which side of the temporal lobe maintains a library of the shapes and objects one expects to recognize in everyday life?
Left
30
What is the MOA of Heparin?
It binds to antithrombin --\> causing inactivation of thrombin NOTE: Heparin is a blood thinner and is used to treat and prevent deep vein thrombosis, pulmonary embolism, and arterial thromboembolism & also myocardial infarction and unstable angina.
31
When do vertical saccades mature and emerge in a baby?
2 months
32
How long does it take for horizontal saccades to emerge and develop?
Emerge: Birth Develop until 24 months
33
When are pursuits seen in babies?
2-4 months
34
When does stereopsis occur in babies?
3-5 months some say 4-6 months Reaches adult: 5-7 years old
35
What should LASIK refractive surgery patients be educated on?
- No eye rubbing - Eye shields should be worn at night while sleeping for approx. 1 week - Swimming in ocean, lakes, rivers, hot tubs, swimming pools, etc. should be avoided for at least 1-2 weeks - No excessive working out for approx. 1 week (especially those with head below the heart or involving Valsalva maneuver) - Eye makeup should be avoided for approx. 1 week - Patients can read, go on the computer, watch TV, etc., but excessive use may cause dryness, so it is advised to use artificial tears often
36
What are some factors that influence the risk for the development of DR? Which is the greatest RF?
Pregnancy, HTN, nephropathy, obesity, hyperlipidemia, and anemia
GREATEST: Duration
37
What is the functional unit of a muscle contraction?
Sarcomere
38
What do multiple sarcomeres make?
A myofibril
39
What is within one sarcomere?
Small filaments called actin and myosin that slide past each other resulting in motion
40
Which of the following topical NSAIDS must be used with caution in a person who is allergic to medications that contain sulfa? Ocufen® (flurbiprofen) Xibrom® (bromfenac) Nevanac® (nepafenac) Acular® (ketorolac)
Xibrom® (bromfenac) NOTE: this drug contains BAK and sodium sulfite. It is important to know medications as well as their preservatives bc sometimes the therapeutic effect is not achieved due to sensitivity to preservatives that are contained w/in the medication
41
Which test relies on birefringence pattern of the macula in order to evaluate an anomaly associated with strabismus and amblyopia?
Haidinger's brushes NOTE: The patient will then see a small rotating bow-tie pattern. This rotating object represents where the fovea projects in object space. It is most commonly accepted that this phenomenon is caused by the birefringence pattern of the radially oriented fibers of Henle's layer around the fovea. Haidinger's brushes are very helpful in the diagnosis of eccentric fixation.
42
IN what situation would a X-chrome contact lens be MOST beneficial?
A Dichromat NOTE: Essentially an X-Chrome contact lens is a red contact lens that acts as a long-pass filter that blocks short wavelengths and allows longer wavelengths to pass through. Patients with abnormal color vision such as dichromats can benefit from this lens in that it aids in color distinction. Wearing the contact lens in one eye effectively shifts the color absorption curve of that eye so that it is different from the other eye; thus allowing the confusion lines of the patient to be altered between the eyes. In order for the lens to work properly, it is essential that the patient be able to easily alternate vision between the eyes for comparison. One of the drawbacks of the lens is that many patients will suppress the eye with the red lens or fuse the images, thereby reducing its effectiveness.
43
A positive plastic spherical surface (n= 1.50) in air has a secondary focal length of 28.52 cm. What equation would correctly solve for the power of the plastic surface?
P=1.50/0.2852 m P= n'/f'. For the above problem, the correct solution would be P= 1.50/0.2852 m, or P= +5.259 (because the surface is positive) or +5.25 D (when rounded to the nearest 0.25 D).
44
What HbA1c is considered normal?
5.7%
45
What HbA1c is pre-diabetic?
5.7 to 6.4%
46
What HbA1c is considered diabetic?
\>6.5%
47
What is the normal postprandial glucose measures in pregnant women to assist in the Dx of gestational DM?
70-141 mg/dL
48
What is the pre-diabetes range for postprandial glucose measures?
141-200 mg/dL
49
What is the diabetic range for postprandial glucose measures?
\>200 mg/dL
50
What is the normal FBS, pre-diabetic FBS, and diabetic FBS?
Normal = \<100 mg/dL Pre-diabetic = 100-125 mg/dL Diabetic = \>125 mg/dL
51
What are the 3 muscular boundaries of the superior carotid traingle?
1. omohyoideus 2. Sternocleidomastoideus 3. Posterior belly of the digastricus
52
A patient with a very dense central corneal scar of his right eye requires his intraocular pressure (IOP) to be measured. Which instruments will yield the MOST accurate reading of his IOP?
Tonopen NOTE: Conditions that can alter central corneal elasticity, such as corneal edema or scarring, may decrease the accuracy of IOP measurement. For these situations it is best to use a McKay-Marg or Tonopen tonometer, which were constructed to better measure corneas with abnormal rigidity. The design of this instrument was created such that the forces of corneal rigidity and surface tension are decreased substantially.
53
What is the approximate volume of the vitreous?
4 mL
54
What is the equation for the optical density of a ND filter?
OD= log(1/T)
55
What are the 2 main components of the vitreous body?
1. Hyaluronic acid 2. Collagen
56
What is the most common type of acquire blepharoptosis?
Aponeurotic (also known as aponeurogenic or involutional) blepharoptosis is the most commonly encountered form of acquired eyelid ptosis (particularly in older adults), representing nearly 60% of cases. It occurs as a result of local dehiscence, stretching, and disinsertion of the levator aponeurosis from its attachments to the tarsus and pretarsal orbicularis muscle. These changes result in a progressive drooping of the upper eyelid.
57
What is the most likely to lead to potentially fatal drop in blood pressure in those taking Viagra (Sildenafil citrate)?
Nitrates Nitrates (such as nitroglycerine) are typically used in the treatment of cardiac conditions as these medications serve as anti-angina agents and coronary artery dilators. Viagra®, when used alone, may also cause vasodilation. Because Viagra® and nitrates both affect nitric oxide levels, if the two are used simultaneously, patients may experience a severe drop in blood pressure and decreased coronary blood flow.
58
Which process contributes the most to aqueous humor production?
Secretion! This accounts for 80-90% of total aqueous humor formation
59
Which part of the 3-mirror lens will you be able to view anterior structures such as the ora serrata?
Bullet mirror (59 degrees)
60
Which part of the 3-mirror lens will you be able to see anterior retina to the equator or peripheral retina?
The middle Square lens (67 degrees)
61
Which part of the 3-mirror lens will you be able to view the retina between the equator and the macula?
The trapezoid mirror (73 degrees)
62
How would you describe the physiologic blind spot on the visual field testing?
Approximately 15 degrees temporal to fixation & slightly below the horizontal plane
63
What is the most common stromal corneal dystrophy?
Lattice dystrophy
64
Which material is has the lightest specific gravity?
Trivex
65
True or False. The longer the axial length of the eye, the greater the vergence required at the corneal plane for an object to be clearly imaged on the retina.
TRUE The far-point vergence relationship can be expressed as the equation A= F(fp) + P (eye), where A= 1.33/a, a= the axial length of the eye, F(fp)= the far point vergence, and P= the power of the reduced eye (+60.00 D). An eye with an increased axial length will require an increased vergence in order for an object to be focused in the retinal plane. An eye with an increased axial length will also have a decreased far point.
66
Choriocapillaris, one of the lamina of the choroid, is continuous anteriorly with what layer of the ciliary body?
None
67
What wavelength of light is most readily absorbed by the photopigment rhodopsin?
507 nm NOTE: 555 nm is the peak for photopic conditions
68
VL/VH is what on an antibody?
the Antigen-Binding site
69
Photoreceptors produce AP or graded potentials?
Grade potentials NOTE: AP's are only produced by Amacrine and Ganglion cells
70
Are photoreceptors hyperpolarized or depolarized in response to light?
Hyperpolarized --\> therefore, reduces glutamate NOTE: increase glutamate in the DARK
71
Your patient complains of her eyelashes touching the back surface of her right spectacle lens. You notice that the lens vertex distance is closer for her right eye compared to that of the left lens. What frame adjustments should solve the patient's complaint?
Reduce the temple spread by bringing in the right temple NOTE: The right lens is closer to the eye, so the vertex distance needs to be increased on the right side in order to balance the frame on her face. Bringing in the right temple increases the force on the frame's right side. This increased force rotates the frame on the nose outward, increasing the right lens vertex distance.
72
In a fetus, what is the name of the blood vessel that shunts the majority of blood away from the liver, delivering it instead to the fetus' heart?
The ductus venosus
73
What acts as a door between the right and left atria in a fetus?
The Foramen Ovale
74
What is the number one cause of hyperthyroidism in the USA?
Graves' disease
75
What is SLK commonly associated with which of the following system conditions?
Thyroid dysfunction
76
What is DNA annealing?
Process by which two strands of nucleotides that are complementary join together, forming a double helix
77
What is the follow % of risk of retinal toxicity in patients taking hydroxychloroquine at 5 years, 10 years, and 20 years?
5 years = \<1% 10 years = 2% 20 years = 20%
78
A trial frame refraction performed on your 78-year-old low vision patient yields a distance prescription of -1.00 DS OU. Using +4.00 DS OU single vision reading glasses with a CCTV set to 16x magnification, what is the equivalent power of this system?
De= (Mrd)(Dadd) De= equivalent Power; Mrd= Magnification of relative distance; Dadd= total add power De= 16x5= 80 D
79
You are managing a patient who presents with anterior uveitis, concurrent hyphema, and elevated intraocular pressure. Which treatment should you avoid in this patient?
Oral aspirin Oral aspirin is contraindicated in the management of uveitis when there is a concurrent hyphema, as aspirin can lead to increased leakage of blood which can worsen the hyphema.
80
What are the fibers that serve to brace and support the zonules?
1. Orbiculociliary division: arises from the pars plana and connects to the ciliary processes 2. Interciliary fibers: runs btwn ciliary processes and connect the processes to each other 3. Circular fibers: run btwn the zonules serving to connect them in a circular pattern like a spider web
81
What are the principal fibers which are important for supporting the lens and accommodation?
The ciliocapsular fibers: arise from the sides and valleys of the ciliary processes and inserts onto the lens
82
What are the divisions of the ciliocapsular fibers?
1. Cilio-posterior-capsular group: runs from sides and valleys of the ciliary processes and inserts onto the lens posterior to the equator 2. Cilio-equatorial-capsular groups: runs from the anterior sides of the ciliary processes and inserts onto the lenticular equator
83
Binding of insulin to its receptor directly activates what enzyme?
Tyrosine kinase Results in phosphorylation of glucose transport protein which then relocates to the cellular membrane where it facilitates the import of glucose
84
What catalyzes the 1st step of glycolysis converting glucose to glucose-6-phosphate?
Hexokinase
85
What enzyme is released by the stomach to aid in the digestion of proteins?
Pepsin
86
Patients with which iris colors have the highest risk of iris color change when using topical PG medications?
Green-brown or yellow brown 50% risk
87
Patients with which mix of eye colors will have lowest risk of pigmentation with PG use?
Pure blue, gray, green, or brown eyes
88
A 6-foot tall man wishes to purchase a plane mirror in which he can visualize his whole length at the same time. How tall must the mirror measure in order for the above to occur?
In order to see full image of a person, the minimum size of the mirror should be one half the person's height. This is so because, in reflection, the angle of incidence is equal to angle of reflection. So, to see the image of a 6 ft tall person, a 3 ft long mirror is required.
89
How much should an edged lens made for an Optyl frame deviate from the measured frame opening?
The edge should be 0.6 to 1.0 mm LARGER than the frame size NOTE: Optyl is a very commonly utilized frame material. Optyl does not shrink when it is heated or cooled, but instead expands with heat; therefore, when making lenses to be placed in an optyl frame, it is best to cut the lenses to be slightly oversized. A deviation of about 0.6 to 1.0 mm larger than the measured frame opening is typical.
90
A patient with 4.50 D of hyperopia wishes to purchase glasses. Which of the following lens modifications can minimize the amount of spherical aberration experienced by the patient when he is looking through his glasses?
Prescribe a lens steeper in the center and flatter in the periphery NOTE: Spherical aberration occurs when parallel light rays incident on a lens that are located further away from the center are bent to a greater degree than axial rays. Spherical lenses (both plus- and minus-powered) result in positive spherical aberration; thus rays of light that are located towards the lens periphery (nonparaxial) are bent more than those that intersect the center of the lens (paraxial rays). Spherical aberration can be minimized by prescribing an aspheric lens for higher powered prescriptions. Aspheric lenses have multiple radii of curvature. A plus powered aspheric lens has a radius of curvature that increases towards the periphery of the lens (the periphery of the lens is flatter than the center). Studies have shown that plano-convex lenses produce smaller amounts of spherical aberration. For hyperopes, a plano-convex lens should be placed with its convex side as the front surface to decrease spherical aberration. Spherical aberration can also be minimized by decreasing the size of the aperture/pupil. Biconvex lenses should not be prescribed, as this type of lens results in more spherical aberration than a plano-convex lens.
91
What type of reflection makes unaided viewing of the anterior chamber angle impossible?
Total internal reflection NOTE: this limitation is overcome with the use of gonioscopy lenses
92
When is total internal reflection ONLY possible?
when n2 \< n1
93
What is the Riddoch phenomenon?
refers to a stimulus that is only observed when it is in motion, and cannot be detected by the observer when static NOTE: may be reported in those who suffer from an occipital lobe lesion, ONH damage, or chiasmal damage
94
What is ESR calculation for females? Males?
Females: [age+10]/2 Males: age/2 Even if ESR testing is normal in patients exhibiting symptoms of GCA, these patients should still undergo a temporal artery biopsy due to the fact that 8-22% of patients with biopsy-proven GCA will show a normal ESR. Additionally, it is important to remember that an elevated ESR is not specific for GCA as it may occur in several other types of inflammatory diseases; however, an elevated ESR with an elevated CRP is considered much more sensitive in diagnosing GCA.
95
What is a high amount of CRP that is considered serious underlying health condition?
350 mg/L Most common cause being severe infection, but a poorly controlled autoimmune disease or severe tissue damage can also lead to this.
96
What is the formula to determine the angle between 2 mirrors?
deviation=360degrees - 2(theta)
97
Sodium fluoresceine is excited primarily by light of which of the following wavelengths?
465 to 490 nm NOTE: this is the range of blue light (435 to 500 nm)
98
What is the most common cause of reduced VA at 1-day post-op LASIK visit?
Dry Eyes The goblet cells & corneal epi may have been damaged during the procedure (from mechanical trauma) causing corneal staining in the early post-op period A great way for determining RE 1 day post-op is retinoscopy --\> test allows clinicians to determine if staie or irregular astigmatism could also be causing the DEC in vision
99
How does iStent & Trabectome INC outflow of aqueous humor?
Bypassing the juxtacanalicular TM & provides access to Schlemm's canal
100
What % of occlusion will you hear a carotid bruit upon auscultation?
50-90% occlusion "Whooshing" sound btwn quick beats of the heart (mid-systole), representing irregular flow of blood around a thrombus in the carotid artery
101
An integral membrane protein that moves 2 compounds simultaneously across a cell membrane in the SAME direction where ONE compound being transported DOWN its concentration gradient and the other AGAINST its gradient is called what?
A symport
102
Do myopes have to converge more or less in contacts vs glasses?
converge MORE they have to accommodate more through CLs. Glasses there is BI.
103
VA remains constant until the target reaches a speed of what?
60 degrees/sec
104
Which structure of the eye is isolated from the immune system & therefore can be classified as antigenic?
The lens This structure is completely avascular & derives all nutrients from aqueous humor
105
Which receptor is moved to the surface of a cell in response to insulin, thus permitting entry of glucose from the bloodstream?
GLUT-4 This receptor exist in lipid micelles w/in cytoplasm of insulin-sensitive cells. When insulin binds its receptor, a cascade of events result in release of these micelles to the surface of the membrane
106
What type of symport facilitates movement of glucose from the intestines into the bloodstream?
SGLT
107
Which slit-lamo biomicroscopy illumination technique utilizes reflected light from the iris or fundus to detect fine endo or epi changes of the cornea?
Retroillumination The use of retroillumination with a slit-lamp biomicroscope is helpful in better visualizing fine corneal epithelial and endothelial changes, such as keratic precipitates, epithelial cysts, and small blood vessels. The technique involves utilizing the reflected light from the iris or fundus (through a dilated pupil) to illuminate the cornea.
108
What is the axial length of the human eye at birth?
Typically ~17 mm INC ~25% by the time child reaches adulthood
109
At birth, what is the power of the cornea?
Typically 48.00D The cornea will lose ~4 to 5.00D of power
110
The normal cornea is prolate or oblate?
Prolate
111
While performing saccadic eye movements, why does the background NOT appear blurred as it moves across the retina?
Selective suppression
112
What is the Tx for acanthomoeba keratitis?
Topical agents: Neosporin (bacitracin, neomycin, polymyxin B) & Brolene (dibrompropamidine isethionate) used in conjunction w one another Due to high potential of blindness & difficulty associated w managing this condition, it is best to refer these pts to a corneal specialist
113
Tx for chlamydia?
Oral doxycycline, tetracycline, or erythromycin, along w topical tetracycline or erythromycin ung
114
Due to its high level of toxicity, which of the following anti-infective medications should ONLY be utilized as a last resort for Tx ocular infections?
Chloramphenicol Chloramphenicol is very lipid-soluble and easily crosses the blood-aqueous barrier; as such, it can cause bone marrow depression (which is reversible), aplastic anemia, gray baby syndrome (occurs if chloramphenicol is given within 2 weeks of birth), optic neuropathy, teratogenesis, and enterocolitis. However, due to chloramphenicol's ability to cross the blood-brain barrier, it is useful in treating staphylococcal brain abscesses and certain types of meningitis.
115
Which organ secretes bicarbonate?
Pancreas
116
When pressure builds up inside the ear, which tube helps to circumvent the excess pressure?
Eustachian tube
117
What type of microorganisms synthesize its own food from inorganic sources?
Autotrophs Inorganic sources=sunlight OR chemical
118
What is a prototroph?
An organism that can synthesize its own amino acids, vitamins, & other nutrients from inorganic compounds
119
What is punctal atresia?
Congenital absence of punctal opening/orifice
120
Subtle broadening of the arteriolar light reflex and mild general attentuation of retinal arteries is seen in which stage of HTN retinopathy?
Stage 1
121
More obvious broadening of the arteriolar light reflex & Salus sign is seen in which stage of HTN retinopathy?
Stage 2
122
Copper-wiring, bonnet sign, Gunn sign, & right-angled deflection of retinal veins are seen in which stage of HTN retinopathy?
Stage 3
123
Which layers of the iris are derived from neural crest?
Anterior border layer & the stroma
124
You are evaluating a 56-year-old female patient and notice a small area of localized hyperpigmentation of the skin on her right upper lid that does not have any associated infiltration or elevation. What is the proper dermatological term for this type of lesion?
Macule Macule: a localized area of color change without any associated infiltration or elevation (the surface is smooth). The lesion may be pigmented (as in a freckle), hypopigmentation (vitiligo), or erythematous (in a capillary hemangioma). The area of change is typically less than 1.5cm in diameter.
125
When analyzing a rigid gas permeable (RGP) contact lens, you measure base curves of 7.67mm (44.50D) and 8.13mm (41.50D) with a radiuscope, and powers of -0.50D and -3.25D on lensometry. What type of toric gas permeable contact lens design do you have?
SPE! If the difference in base curves is equal to the difference in contact lens powers then you have a spherical power effect (SPE) bitoric lens design -For the above patient difference in base curves is 3.00D and difference in CL powers is 2.75D -3.00 is essentially equal to 2.75; therefore, this lens is an SPE bitoric design -Again, note that "equivalent" is defined as less than or equal to 0.50D - If the difference in base curves is not equivalent to the difference in CL powers, and 3/2 x the difference in base curves is also not equal to the difference in CL powers then you have a cylinder power effect (CPE) bitoric lens Remember: steeper meridian has more minus vs flatter more plus (44.50:-3.25 & 41.50: -0.50)
126
A circle of light is projected onto a patient's cornea from a distance of 9.0 cm. The resulting Purkinje image I is elliptical, with its long axis located horizontally. Which type of astigmatism is this patient MOST likely to possess?
WTR Bc the pts cornea is steeper vertically which minimized the image in this meridian, creating an ellipse w a horizontal axis
127
What is the most likely systemic condition that presents with anterior granulomatous uveitis?
Syphilis Causes: KP's that have greasy (or mutton fat) appearance, along w iris nodules
128
What are the major proteins found in the tears?
Albumin Lysozymes Lactoferrin IgA IgG Secretory component Glycoproteins Anti-proteinases Tissue plasminogen activator & epidermal growth factor
129
What is the function of lysozymes & lactoferrin in the tears?
Bother are bacteriostatic Lysozymes: hydrolytic Lactoferrin: chelates iron which is needed for bacterial function
130
What is the importance of tissue plasminogen activator and epidermal growth factor in the tears?
Both are required to activate plasmin which is necessary for wound healing
131
What grade is it according to the SUN study if you see 30 cells?
Grade 3 Grade / Cells in Field 0 / \<1 0.5+ / 1 - 5 1+ / 6 - 15 2+ / 16 - 25 3+ / 26 - 50 4+ / 50+
132
A patient with a very dense central corneal scar of his right eye requires his intraocular pressure (IOP) to be measured. Which instrument will yield the MOST accurate reading of his IOP?
Tonopen! Conditions that can alter central corneal elasticity, such as corneal edema or scarring, may decrease the accuracy of IOP measurement. For these situations it is best to use a McKay-Marg or Tonopen tonometer, which were constructed to better measure corneas with abnormal rigidity. The design of this instrument was created such that the forces of corneal rigidity and surface tension are decreased substantially.
133
What is anterior myoepithelium (dilator muscle included), the posterior pigmented epithelium, and sphincter muscle derived from?
Neuroectoderm
134
A 64-year-old female with allergic rhinoconjunctivitis, hypertension, and chronic open-angle glaucoma presents for a routine follow-up. Her intraocular pressures are noted to be markedly elevated despite compliance with her glaucoma regimen. Which of the following recently added medications is the MOST likely cause?
Fluticasone furoate (Veramyst) intranasal spray Fluticasone furoate is an intranasal corticosteroid that has been shown to raise intraocular pressures in susceptible patients. The overall incidence of this effect is less than 2%. It is important to note that clinical trials with other intranasal steroids have not demonstrated any significant rise in intraocular pressures.
135
What is postural hypotension (orthostatic) a result of?
Blood pooling in the lower etremities due to gravitational forces when a change of position to standing occurs
