02 - Fundamentals and Principles of Ophthalmology 1. If all the nerves passing through the annulus of Zinn were transected, what nerve would continue to function? a. superior division of cranial nerve III b. cranial nerve IV IV c. nasociliary branch of cranial nerve V (V1) d. optic nerve 2. Which extra ocular muscle originates from the annulus of Zinn? a. levator palpebrae superioris b. superior oblique oblique c. lateral rectus d. inferior oblique 3. What is the ratio of optic nerve axons that cross at the optic chiasm to those that do not cross at the optic chiasm? a. 67:33 b. 50:50 c. 30:70 d. 53:47 4. A patient presents with left-sided ophthalmoplegia and forehead numbness. The lesion is most likely to be located at the a. brainstem b. cavernous sinus sinus c. superior orbit d. intraconal space 5. The first cells to develop in the embryonic retina are the a. ganglion cells b. photoreceptors photoreceptors c. amacrine cells d. bipolar cells
6. Which disorder is associated with a defect in a non mitochondrial gene? a. Leber hereditary optic neuropathy b. chronic progressive progressive external external ophthalmoplegia ophthalmoplegia c. neuropathy, ataxia, and retinitis pigmentosa d. retinoblastoma retinoblastoma 7. What characteristic of retinoblastoma may facilitate its diagnosis as a familial condition? a. It may be associated with chromosome chromosome 11 short-arm deletion syndrome syndrome and Wilms tumor. b. It affects approximately approximately 1 per 100,000 live births births in the United United States. c. Approximately 90% of patients with hereditary retinoblastoma have a family history of the disease. d. The hereditary pattern in familial retinoblastoma is autosomal dominant, but the defect is mitochondrial at a cellular level. 8. Mutations in the rhodopsin gene are associated with what inherited ocular disease? a. juvenile glaucoma b. Leber hereditary hereditary optic neuropathy neuropathy c. retinitis pigmentosa d. Stargardt disease 9. Mitochondrial inheritance is transmitted by what route? a. paternal mitochondria b. maternal mitochondria mitochondria c. acquired mitochondria d. de novo mitochondria 10. Mutations of PAX6 are associated with what disorder? a. aniridia b. retinal coloboma coloboma c. renal hypoplasia d. corneal granular dystrophy
11. An unaffected woman has a brother, maternal uncle, and son affected with retinitis pigmentosa. What is the most likely mode of inheritance? a. autosomal dominant b. X-linked recessive recessive c. autosomal recessive d. sporadic 12. What is the basis for complex genetic diseases? a. a single recessive gene b. X-linked genes genes c. a single spontaneous genetic mutation d. the resultant effect of many genes, in combination with health habits and environmental factors 13. What structure, if inflamed, would be considered a sign of uveitis? a. optic nerve b. Descemet membrane membrane c. choroid d. retinal pigment epithelium 14. What pair accurately matches a cell-type origin with the correct tearlayer product? a. goblet cells- lipid layer b. meibomian glands-mucin glands-mucin layer layer c. glands of Krause-aqueous layer d. glands of Wolfring-mucin Wolfring-mucin layer 15. What option most accurately describes the immunoglobulin(s) that can be found in the tear film? a. IgA only b. IgA and IgG only c. IgG and IgM only d. IgA, IgG, IgM, and IgD 16. What intraocular structure is a true basement membrane (basal lamina)? a. Bowman layer b. zonule of Zinn Zinn c. Descemet membrane d. anterior border layer of iris
17. What is the principal structural protein in the Descemet membrane? a. type I collagen b. type II collagen collagen c. type III collagen d. type IV collagen 18. What mechanism holds the flap created during laser in situ keratomileusis (LASIK) in place after surgery? a. endothelial- Descemet membrane interaction b. endothelial pump pump c. Bowman layer- stromal adhesions d. Stromal collagen adhesions 19. What property of the retina renders it susceptible to oxidative stress? a. high content of polyunsaturated polyunsaturated fatty acids in photoreceptor outer segments segments b. high concentration concentration of carotenoids carotenoids compared compared with other intraocular intraocular structures structures c. presence of vitamin E d. absence of retinal vessels in the foveal avascular zone 20. What pigment within the retinal pigment epithelium is responsible for the signal generated in fundus auto fluorescence imaging? a. melanin b. lipofuscin c. rhodopsin d. lutein 21. The retinal pigment epithelium is the first site of melanogenesis in the body. Ocular melanin has been shown to participate in what process? a. pathogenesis of retinitis pigmentosa b. vitamin A metabolism metabolism c. retinal adhesion d. retinal development and neuronal migration 22. Age-related loss of type IX I X collagen has been implicated in what process related to the vitreous? a. vitreous hemorrhage b. angiogenesis c. increased diffusion of oxygen from the anterior segment into the posterior segment d. vitreous liquefaction
23. What vitamin is most critical for the photoreceptor response to light? a. A b. B c. C d. E 24. In prescribing for elderly patients, what pharmacologic pharmacologic adjustments must be considered? a. Hepatic perfusion and enzymatic activity increase with age. b. Renal function function decreases with with age. c. Elderly patients have more albumin relative to weight. d. Elderly patients have more body water relative to weight. 25. What technique or strategy improves the ocular absorption of eye drops? a. rapid instillation of eye drops one after the other without interruption b. application of digital pressure pressure at the lateral canthus canthus to prevent the the eye drop from escaping c. keeping the eye open and rolling the eye around after instillation of each drop d. increasing the viscosity of the delivery vehicle 26. Atropine, 1%, has how many milligrams milligrams of drug per drop, assuming 20 drops per milliliter? a. 1 mg b. 0.5 mg c. 0.1 mg d. 0.05 mg 27. How much epinephrine is present in 1 mL of the 1:10,000 epinephrine solution? a. 1 mg of epinephrine b. same amount of epinephrine epinephrine as in 1 mL of 0.01% epinephrine epinephrine c. same amount of epinephrine as in 1 mL of 1:1000 epinephrine d. same amount of epinephrine as in 1 mL of 0.1% epinephrine 28. Direct-acting muscarinic agents (miotics) have what clinical effect? a. hyperopic shift in refraction b. increased range range of accommodation accommodation c. central anterior chamber deepening d. increased night vision
29. What management strategy has been shown to reduce postsurgical endophthalmitis? a. preoperative preparation of the eye with topical povidone-iodine b. intracameral intracameral vancomycin c. intracameral aminoglycosides aminoglycosides d. subconjunctival subconjunctival fluoroquinolones fluoroquinolones 30. What property of latanoprost may limit its usefulness? a. It is a pro drug of prostaglandin E20. b. It reduces intraocular intraocular pressure pressure by increasing increasing trabecular meshwork outflow. c. It can cause darkening of the iris and periocular skin and hypertrichosis of the eyelashes. d. It increases the number of melanocytes. 31. What systemic side effect may result from treatment with oral carbonic anhydrase inhibitors? a. insomnia b. weight gain c. hyperkalemia d. aplastic anemia 32. What is a clinically important important property of brimonidine? a. Brimonidine is a selective a 1-adrenergic 1 -adrenergic agonist. b. Brimonidine Brimonidine is more lipophilic lipophilic than apraclonidine. apraclonidine. c. Brimonidine has been associated with tachycardia and hyperventilation when used in infants. d. Rates of tachyphylaxis and allergic reaction are higher in brimonidine than in apraclonidine.
Answers 1. b. Cranial nerve IV passes through the superior orbital fissure but not through the annulus Of Zinn. 2. c. The lateral rectus muscle originates from the annulus of Zinn. The superior, inferior, medial, and lateral rectus muscles all arise from the annulus of Zinn. 3. d. Anatomical studies demonstrate that more axonal fibers cross at the optic chiasm than do not cross, in a 53:47 ratio. 4. b. The cavernous sinus is where the trigeminal nerve (ophthalmic (ophthalmic branch) and the nerves controlling eye movement are in proximity to one another. 5. a. The ganglion cells are the first cells to differentiate in the embryonic eye. 6. d. The hereditary pattern in familial retinoblastoma retinoblastoma is autosomal dominant and associated with a mutation in the nuclear tumor-suppressor tumor-suppressor gene on chromosome 13 (the retinoblastoma, or RBl, or RBl, gene). The other conditions named have been associated with mutations in mitochondrial genes. 7. c. The retinoblastoma gene is located on the long arm of chromosome 13. The aniridia gene, PAX6, gene, PAX6, and the Wilms tumor gene are a re adjacent on chromosome 11; their proximity is important to recognize, as children with aniridia need to be screened for Wilms tumor. Retinoblastoma Retinoblastoma occurs at a rate of approximately 1 per 15,000-20,000 li\e births. Most cases of retinoblastoma are unilateral and not inherited. Of people who inherit the gene mutation, 90% will develop retinoblastoma (90% penetrance). 8. c. More than 100 different mutations in the rhodopsin gene are known to cause retinitis pigmentosa. Juvenile glaucoma is associated with myocilin mutations, Leber hereditary optic neuropathy is associated with mitochondrial DNA mutations, and Stargardt disease is associated with ABCA4 with ABCA4 gene mutations. 9. b. A significant number of disorders associated with the eye or visual system involve mitochondrial deletions or mutations. Because a fertilized embryo receives most of its mitochondria from the egg (maternal side), mitochondrial disease should be considered whenever the inheritance pattern of a trait suggests maternal transmission. transmission.
10. a. A PAX6 A PAX6 mutation is associated with aniridia. The PAX6 The PAX6 gene product is a transcription factor that is required for normal development of the eye. Almost all cases of aniridia are the result of PAX6 of PAX6 mutations. 11. b. Three affected males connected through an unaffected female suggest an X-linked inheritance. The other modes are possible but much less likely. 12. d. Many common eye diseases are complex genetic diseases involving the effects of multiple genes. Examples include glaucoma, age-related macular degeneration, and myopia. The combined effects of many genes, along with health habits and environmental factors, result in the disease. 13. c. The optic nerve, cornea, and retinal pigment epithelium are not part of the uvea. The uveal tract is the main vascular compartment of the eye and consists of the iris, ciliary body, and choroid. 14. c. Goblet cells produce the mucin layer, and meibomian glands form the lipid layer. Glands of Krause and Wolfring produce the aqueous layer. 15. d. Proteins in the tear film include immunoglobulin immunoglobulin A (IgA) and secretory IgA (sigA). IgA is formed by plasma cells in interstitial tissues of the main and accessory lacrimal glands and by the substantia propria of the conjunctiva. The secretory component is produced within lacrimal gland acini, and sigA is secreted into the lumen of the main and accessory lacrimal glands. IgA plays a role in local host -defense mechanisms mechanisms of the external eye, as shown by increased levels of IgA and IgG in human tears associated with ocular Inflammation. Other immunoglobulins immunoglobulins in tears are IgM, IgD, and IgE. Vernal conjunctivitis causes elevated tear and serum levels of IgE, increased IgE producing plasma plasma cells in the the giant papillae of the superior tarsal tarsal conjunctiva, conjunctiva, and elevated histamine levels. 16. c. The Descemet membrane is a true basement membrane produced by the basolateral surfaces surfaces of the basal layer of the the corneal endothelium. endothelium. 17. d. The Descemet membrane is a 10-12-f.Lm 10 -12-f.Lm-thick -thick basement membrane between the endothelium endothelium and the posterior corneal stroma. stroma. Type IV IV collagen is the most abundant collagen in the Descemet membrane. Type I collagen, however, is the major collagen component of the corneal stroma.
18. b. The endothelial pump is responsible for generating the negative hydrostatic pressure that is necessary for holding the laser in situ keratomileusis (LASIK) flap in place after surgery. 19. a. polyunsaturated fatty acids have increased numbers of carbon-carbon double bonds, which enhances their susceptibility to lipid peroxidation. Other aspects of the retina that increase its susceptibility to oxidative stress include an increased concentration of mitochondria, a high oxygen tension, and photo-oxidation photo-oxidation triggered by light exposure. exposure. 20. b. Lipofuscin molecules are the fine yellow-brown pigment granules of the retina. They are thought to be "wear-and-tear" deposits deposits resulting from phagosomal activity. activity. Histologically, Histologically, lipofuscin lipofuscin stains with with Sudan stain and exhibits auto fluorescence. 21. d. Melanin acts as a neutral-density filter on all wavelengths of light. Patients with oculo cutaneous albinism have foveal hypoplasia and more contralateral projections of the retinal ganglion ganglion cells, thought thought to be due to reduced melanin melanin levels resulting from defects in the tyrosinase gene. Additional functions of melanin include stabilization of free radicals and detoxification. 22. d. Vitreous liquefaction, also known as syneresis, as syneresis, begins begins with the breakdown of collagen fibrils into smaller fragments. This liquefaction is thought to occur because of a loss loss of "shielding" "shielding" of type type II collagen by type type IX collagen. This This process has no direct effect effect on the development development of vitreous hemorrhage unless unless it leads to the development of posterior vitreous detachment (PVD). A PVD can protect against retinal neovascularization neovascularization by eliminating the scaffold for fibrovascular proliferation. Oxygen tension increases in the posterior chamber in post vitrectomized eyes. 23. a. 11-cis-retinal is a vitamin A derivative. Vitamins C and E play antioxidant roles in the retina but do not participate in the light response of the retina. 24. b. Compared with younger patients, older patients have less lean body mass because of decreased decreased muscle bulk, bulk, less body water, decreased albumin, albumin, and increased relative adipose tissue. These physiologic differences alter tissue binding and drug drug distribution. distribution. Human renal function decreases with age. Hepatic perfusion and enzymatic activity decrease with age.
25. d. Increased viscosity of the vehicle generally increases drug retention in the inferior culde-sac, aiding drug penetration. 26. b. A 1% solution has 1 g/ 100 mL, or 1000 mg/ 100 mL, of active ingredient. Assuming there are 20 drops/mL, 1 drop contains 0.05 mL of drug. Multiplying 1000 mg/100 mL x 0.05 mL yields 0.5 mg per drop of atropine available for systemic absorption. 27. b. A 1:10,000 dilution has 1 g of drug in 10,000 mL (or 1000 mg/10,000 mL). This concentration is equivalent to a 0.01% solution (0.01 g/100 mL, or 10 mg/100 mL). One milliliter of the 1:10,000 dilution of epinephrine contains 0.1 mg of epinephrine. If the concentration c oncentration of the solution increases to 1:1000, 0.1 mL of it contains the same amount of epinephrine as in 1 mL of the 1:10,000 solutions. 28. b. Miotic agents constrict the pupillary sphincter and the ciliary muscle. Ciliary muscle contraction results results in increased myopia and a decreased central anterior chamber. Pupillary constriction causes decreased night vision but increases the range of accommodation accommodation (pinhole effect). 29. a. Topical povidone-iodine solution, 5%, exhibits broad-spectrum antimicrobial activity when used to prepare the surgical field and rinse the ocular surface. It has been shown to have a significant effect on postsurgical endophthalmitis. 30. c. Latanoprost is a prodrug of prostaglandin F2a that reduces the intraocular pressure primarily primarily by increasing increasing the uveoscleral uveoscleral outflow. It increases the number of melanosomes (increased melanin content, or melanogenesis) within the melanocytes but has not been shown to cause melanocytosis (increased number of melanocytes). 31. d. Use of oral carbonic anhydrase inhibitors can cause paresthesias, imbalance, anorexia, weight loss, hypokalemia, hypokalemia, somnolence, kidney stones, metabolic acidosis, and aplastic anemia. 32. b. Brimonidine is a selective a2-adrenergic agonist. It is more lipophilic than apraclonidine and penetrates the blood- brain barrier better. Its use in infants is contraindicated, and it should be used with caution in small children because of severe systemic toxicities, in particular bradycardia and apnea. Brimonidine has lower rates of tachyphylaxis and allergic reaction than apraclonidine.
