test #3 Flashcards
Which cranial nerve do you associate with the second branchial arch and its derivative structures?
X
VII
III
V
Which cranial nerve do you associate with the second branchial arch and its derivative structures?
VII
Explanation
Each of the branchial arches has a single cranial associate with it. The frontonasal process above the first branchial arch is innervated by the ophthalmic division of CN V. The maxillary and mandibular divisions of the Vth cranial nerve innervate the upper maxillary and lower mandibular processes of the first branchial arch. The cranial nerve associated with the second branchial arch is CN VII. The third branchial arch is associated with CN IX. The composite of branchial arches 4-6 receive their innervation from CN X.
Upon slit-lamp examination of your 81 year-old male patient, you observe the presence of an age-related cataract in which there is significant liquefaction such that the nucleus of the crystalline lens begins to sink inferiorly. This type of cataract is known as which of the following?
Morgagnian cataract
Immature cataract
Mature cataract
Hypermature cataract
Upon slit-lamp examination of your 81 year-old male patient, you observe the presence of an age-related cataract in which there is significant liquefaction such that the nucleus of the crystalline lens begins to sink inferiorly. This type of cataract is known as which of the following?
Morgagnian cataract
Explanation
When classifying the maturity of an age-related cataract, there are several factors to consider, including the cloudiness of the lens, the appearance of the capsule, and the location of the lens nucleus. Immature cataracts are those in which the lens is partially opaque. A mature cataract will present with a completely opaque crystalline lens. Hypermature cataracts also have a completely opaque appearance to the lens, in addition to showing wrinkling and shrinking of the anterior capsule due to leakage of water out of the lens. Morgagnian cataracts are hypermature cataracts in which there is significant liquefaction such that the nucleus of the crystalline lens begins to sink inferiorly.
Which of the following human leukocyte antigen (HLA) types is associated with Bechet’s syndrome?
HLA-A29 HLA-B51 HLA-B7 HLA-DR2 HLA-B27
Which of the following human leukocyte antigen (HLA) types is associated with Bechet’s syndrome?
HLA-B51
Explanation
- HLA-B51: Bechet’s syndrome
- HLA-B27: Spondyloarthropathies (ankylosing spondylitis)
- HLA-A29: Birdshot chorioretinopathy
- HLA-B7 & HLA-DR2: Presumed ocular histoplasmosis syndrome (POHS) and acute multifocal placoid pigment epitheliopathy (AMPEE)
Contraction of the ciliary muscle leads to which of the following?
The lens becomes more spherical and increases refractive power, bringing distant objects into focus
The lens becomes more oblong and loses refractive power, bringing distant objects into focus
The lens becomes more spherical and increases refractive power, bringing near objects into focus
The lens becomes more oblong and increases refractive power, bringing near objects into focus
The lens becomes more oblong and loses refractive power, bringing near objects into focus
Contraction of the ciliary muscle leads to which of the following?
The lens becomes more spherical and increases refractive power, bringing near objects into focus
Explanation
Contraction of the ciliary muscle decreases the diameter of the ring formed by the ciliary body. This releases tension on zonule fibers and allows the lens capsule to become more spherical. The anterior surface curve increases and the lens becomes thicker. This increases refractive power (a.k.a. accommodation) and brings near objects into focus on the retina. Another school of thought believes that ciliary body contraction causes an increase in the vitreal mass which causes the vitreous to push the lens forward allowing for clearer near acuity. When the ciliary muscle relaxes, the eye is considered at rest for distant vision.
An acute staphylococcal abscess of a lash follicle in an external hordeolum is MOST commonly associated with which of the following glands?
Glands of Krause Glands of Wolfring Meibomian gland Glands of Moll Glands of Zeis
An acute staphylococcal abscess of a lash follicle in an external hordeolum is MOST commonly associated with which of the following glands?
Glands of Zeis
Explanation
An external hordeolum is an acute staphylococcal abscess of an eyelash follicle that is most commonly associated with the glands of Zeis, and less likely the glands of Moll. Patients typically present with a localized area of redness, tenderness, and swelling surrounding an eyelash follicle. The lesion will usually develop a whitish-yellow point at the surface of the lid margin. In most cases, it will drain spontaneously within several few days; however, the use of warm compresses usually speeds up the drainage process. In some cases, epilation of the affected eyelash may be considered to allow a channel and promote drainage.
An internal hordeolum is an infection associated with the meibomian glands. The infection commonly results in blockage of the gland creating swelling, redness, warmth, and tenderness within the tarsus. The course of an internal hordeolum is typically more prolonged and usually requires more extensive treatment.
A 66 year-old male presents to your office with a chief complaint of blurred vision, redness, and pain in his left eye. Upon examination you conclude that he is undergoing an acute angle closure attack. You decide to administer an oral acetazolamide to control IOP. What is the proper initial dosage for this medication in office?
Two 250mg Diamox® tablets by mouth
Two 500mg Diamox Sequel® capsules by mouth
One 500mg Diamox Sequel® capsule by mouth
Four 250mg Diamox® tablets by mouth
A 66 year-old male presents to your office with a chief complaint of blurred vision, redness, and pain in his left eye. Upon examination you conclude that he is undergoing an acute angle closure attack. You decide to administer an oral acetazolamide to control IOP. What is the proper initial dosage for this medication in office?
Two 250mg Diamox® tablets by mouth
Explanation
According to the AOA Clinical Practice Guidelines for Care of the Patient with Primary Angle Closure Glaucoma, an oral carbonic anhydrase inhibitor (CAI) such as acetazolamide (Diamox) should be given immediately upon diagnosis when the patient is not nauseated. Diamox is available in 125-250mg tablets or in a 500mg sustained released capsule (Sequel). A 500mg dose (two 250mg tablets) of Diamox in office is most commonly used. The 500mg Diamox Sequel should be avoided because it is a timed-release formulation; therefore, it has a slower onset of action. When a patient is nauseous, 500mg of intravenous acetazolamide should be administered.
Remember that acetazolamide should be avoided in patients with kidney problems; in such cases, 100mg of methazolamide (Neptazene) becomes the CAI treatment of choice. CAIs are sulfa-based drugs and should also be avoided in patients with a known sulfa allergy.
Upon dilated fundus examination of your patient, you detect what appears to be elevation of the optic disc in both eyes. Which of the following observations would aid in distinguishing the presence of buried optic disc drusen from a diagnosis of optic disc edema?
Anomalous vascular patterns commonly occur in association with the presence of optic disc drusen
Vessels coursing the surface of the optic disc are usually obscured in patients with optic disc drusen
Hyperemia of the disc is typically present in patients with optic disc drusen
Spontaneous venous pulsation is usually absent in patients with optic disc drusen
Upon dilated fundus examination of your patient, you detect what appears to be elevation of the optic disc in both eyes. Which of the following observations would aid in distinguishing the presence of buried optic disc drusen from a diagnosis of optic disc edema?
Anomalous vascular patterns commonly occur in association with the presence of optic disc drusen
Explanation
Buried optic disc drusen may mimic papilledema due to the fact that the drusen lie deep beneath the surface and are difficult to view. Optic disc drusen often lead to elevation of the optic disc. There are, however, several distinguishing factors that may aid in the clinical diagnosis of optic disc drusen versus possible papilledema.
- Anomalous retinal vascular patterns commonly occur in association with the presence of optic disc drusen; this may include early vascular branching and increased vessel tortuosity
- Vessels coursing the optic disc in patients with optic disc drusen are not obscured, despite the presence of disc elevation; those presenting with papilledema will commonly exhibit obscuration of these vessels due to edema of the retinal nerve fiber layer
- Hyperemia of the optic disc is associated with papilledema and does not occur in patients with optic disc drusen
- About 80% of patients with optic disc drusen demonstrate a spontaneous venous pulsation (SVP), while the loss of SVP is one of the earliest signs of papilledema
Which 2 of the following statements are TRUE in regards to gas-permeable contact lens designs? (Select 2)
Toric peripheral curves result in an oval optic zone and spherical peripheral curves result in a circular optic zone
SPE bitoric contact lenses act optically like a spherical lens
Flexure of a gas-permeable contact lens will result in an increase in over-refraction cylinder in the opposite meridian of the corneal toricity
Polishing or adding power to a front surface toric contact lens is an easy, in-office modification
Optics of bitoric contact lenses are usually not as crisp as those of the base curve toric design
Which 2 of the following statements are TRUE in regards to gas-permeable contact lens designs? (Select 2)
SPE bitoric contact lenses act optically like a spherical lens
Optics of bitoric contact lenses are usually not as crisp as those of the base curve toric design
Explanation
The following statements are true in regards to gas-permeable contact lenses:
SPE bitoric contact lenses act optically like a spherical lens
- When prescribed, SPE bitoric lenses will not have any effect on the over-refraction cylinder, and lens rotation on the eye will not alter vision or the refractive error measured; therefore, they are typically used in patients with high amounts of corneal cylinder and low amounts of residual astigmatism (when a spherical diagnostic lens is placed on the eye)
Optics of bitoric contact lenses are usually not as crisp as those of the base curve toric design
- In cases where a CPE bitoric lens is considered, it is important to first rule out the possibility of a base curve toric lens
- These lenses tend to be cheaper, have better optics, and in-office modification and polishing are possible
Polishing or adding power to a base curve toric contact lens is an easy, in-office modification due to the spherical front surface of the lens
Toric peripheral curves result in a circular optic zone, and spherical peripheral curves result in an oval optic zone
- With spherical peripheral curves, the meridian with the flatter base curve will have the larger optic zone diameter
- Toric peripheral curves typically allow for better lens stabilization
Flexure of a gas-permeable contact lens will result in an increase in over-refraction cylinder in the same meridian of the corneal toricity
- If a gas-permeable lens flexes or warps on an against-the-rule cornea there will be an increase in against-the-rule cylinder in the over-refraction
- On a with-the-rule cornea, lens flexure will lead to an increase in with-the-rule cylinder, which may be beneficial in cases where a decrease in against-the-rule cylinder is desired
Which 2 of the following pupil anomalies would provide anisocoria that is more prevalent in dim lighting? (Select 2)
Argyll Robertson pupil Marcus Gunn pupil Oculomotor palsy Acute Adie's tonic pupil Horner's syndrome Physiologic anisocoria
Which 2 of the following pupil anomalies would provide anisocoria that is more prevalent in dim lighting? (Select 2)
Argyll Robertson pupil
Horner’s syndrome
Explanation
When investigating the etiology of a pupil abnormality, it is important to first determine which pupil is affected; this is accomplished by measuring the pupil diameter sizes in both bright and dim light. Cases in which anisocoria is more prevalent in bright lighting suggests that the abnormal pupil is the larger pupil, as it will not constrict in the presence of light. Anisocoria that is more obvious in dim lighting suggests that the smaller pupil is abnormal because it does not dilate at the same rate as the normal pupil.
Possible causes of an abnormally miotic pupil in which anisocoria is greater in dim light:
- Horner’s syndrome: in addition to a miotic pupil, patients will also present with a mild ptosis on the affected side, along with possible anhidrosis
- Argyll Robertson pupil: the pupil will typically have an abnormal shape in addition to exhibiting a poor reaction to light but will constrict normally upon accommodation to a near target; although Argyll Robertson pupils are bilateral, there is usually a mild degree of asymmetry present
- Iritis: patients will also complain of pain and redness, and cells and/or flare will be observable in the anterior chamber upon slit-lamp evaluation
- Unilateral use of miotic agent: typically has a history of getting some type of pharmacologic agent in the eye, or rubbing the affected eye with a hand that inadvertently came in contact with a miotic agent
- Long-standing Adie’s pupil: Adie’s pupils will initially present dilated but may become miotic over time; typically, there will also be an irregular and slow reaction to light stimuli
The ligaments that suspend the lens (zonules) are embryonically derived from what structure?
The lens epithelium
The primary vitreous
The lens capsule
The tertiary vitreous
The ligaments that suspend the lens (zonules) are embryonically derived from what structure?
The tertiary vitreous
Explanation
The zonules are attached to the posterior and anterior surfaces of the lens and connect to the pars plana of the ciliary body. The primary vitreous develops from weeks 3 through 9. The secondary vitreous then begins to form and condenses the primary vitreous forming Cloquet’s canal. Developmentally, the tertiary vitreous is secreted last; the zonules are comprised of condensed tertiary vitreous.
You wish to evaluate your patient’s overall tear production. Which of the following tests assesses the volume of reflex AND basal tear secretions?
Schirmer I test
Jones I dye test
Schirmer II test
Phenol red thread test
You wish to evaluate your patient’s overall tear production. Which of the following tests assesses the volume of reflex AND basal tear secretions?
Schirmer I test
Explanation
The Schirmer I test is performed without anesthetic and therefore measures both the basal and reflex tear secretions. This test is conducted by placing a small strip of paper in the temporal region of the inferior cul-de-sac of the eye. The room illumination is dimmed and the patient is asked to blink normally. After five minutes, the length of the paper that is moist is measured. If greater than 10 mm of the paper is wet, the tear production is considered normal. The Schirmer II test is performed in conjunction with anesthetic, and therefore measures the basal tear production. Prior to the test, anesthetic is instilled into the eye. After one minute, the tears and excess anesthetic are removed from the inferior cul-de-sac. The test is then performed in the same fashion as the Schirmer I test. If greater than 5 mm of the paper is wet, the tear production is normal. Alternatively, the basal levels of tear secretion can be investigated by placing a specially coated thread (phenol red thread test) at the outer canthi of each eye for 15 seconds. The amount of thread that turns bright red (due to wetting of the phenol red dye) should measure greater than 10 mm for a normal result. The Jones I test evaluates the integrity of the tear drainage system. Sodium fluorescein is placed into the patient’s eyes, and after five minutes the patient is asked to blow their nose. The tissue is evaluated for dye or, alternatively, a cotton-tipped applicator may be placed under the inferior turbinate and evaluated for the presence of dye. If dye is not observed, then there may be a blockage of the drainage system.
Light falls onto an air-water interface. Assuming normal incidence, which of the following equations would allow you to solve for the percentage of light that is reflected? (index of water is 1.33)
R= (1.33+1.0)2/(1.33-1.0)2
R= (1.0+1.33)2/(1.0-1.33)2
R= (1.0-1.33)2/(1.0+1.33)2
R= (1.33-1.0)2/(1.33+1.0)2
Light falls onto an air-water interface. Assuming normal incidence, which of the following equations would allow you to solve for the percentage of light that is reflected? (index of water is 1.33)
R= (1.33-1.0)2/(1.33+1.0)2
Explanation
Fresnel’s law of reflectance states that some amount of light is reflected at each surface, which then decreases the amount of transmitted light. The equation is as follows: R = (n2-n1)2/(n2+n1)2 , where R= reflectance (assuming normal incidence), n2= the index of the second medium, and n1= the index of the first medium. Solve for R= (1.33-1.0)2/(1.33+1.0)2, R= (0.1089)/(5.43)=0.020 or 2%. This finding is important for ophthalmic lenses, especially those of higher index which reflect more light. Makers of optical devices can minimize reflectance by adding anti-reflective coatings.
Which 3 of the following carotenoids are considered the predominant pigments found in the macula lutea? (Select 3)
Meso-zeaxanthin Canthaxanthin Lutein Zeaxanthin Lycoxanthin Rhodoxanthin
Which 3 of the following carotenoids are considered the predominant pigments found in the macula lutea? (Select 3)
Meso-zeaxanthin
Lutein
Zeaxanthin
Explanation
The major functional roles of the carotenoid pigments found in the human macula are protection against ultraviolet light-induced retinal damage (as they act as filters for blue light), and limiting oxidative stress (with their high antioxidant potential). The predominant carotenoids that make up this macular pigment include lutein, zeaxanthin, and meso-zeaxanthin (which is a conversion product of lutein). They are selectively concentrated in the macula lutea and are responsible for the yellow appearance of this region. Humans cannot synthesize these pigments de novo; therefore, they must be derived entirely from the diet. Certain eye diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP) have been associated with low levels of lutein, zeaxanthin, and meso-zeaxanthin.
The retinal pigment epithelium (RPE) is continuous anteriorly with what layer of the ciliary body?
Pigment epithelium of the ciliary body
Non-pigmented epithelium of the ciliary body
Internal limiting membrane of the ciliary body
Basal lamina of the ciliary body
The retinal pigment epithelium (RPE) is continuous anteriorly with what layer of the ciliary body?
Pigment epithelium of the ciliary body
Explanation
The RPE is continuous with the pigmented epithelium of the ciliary body. To make this easier to remember, recall that pigment stays with pigment.
Which of the following agents is frequently utilized to remove calcium deposits from the cornea?
British anti-lewisite (BAL)
Zinc
Deferoxamine
Ethylenediaminetetraacetate (EDTA)
Which of the following agents is frequently utilized to remove calcium deposits from the cornea?
Ethylenediaminetetraacetate (EDTA)
Explanation
Band keratopathy is characterized by a band-like deposition of calcium in the central portion of the cornea. Removal of calcium requires the use of a topical anesthetic followed by the application of EDTA. EDTA chelates calcium, enabling large plaques of calcium to be scraped off the cornea. BAL, also known as dimercaprol, can be used ophthalmically to prevent corneal damage from arsenic compounds. BAL was initially developed during the war as an antidote to exposure to lewisite, an arsenic-based chemical warfare agent. BAL can be used for the chelation of heavy metals such as nickel, gold, and mercury. Deferoxamine binds to iron and can be utilized to remove corneal rust rings. Zinc is not a chelating agent.
