B. NADPH. These agents are found along the sorbitol pathway. This pathway is important in understanding the breakdown of glucose in the body. One molecule of glucose can either undergo reduction to sorbitol in a low oxygen environment or can be converted directly to fructose 6-phosphate.

D. Epinephrine is derived from Tyrosine. Tyrosine molecules are converted to dopamine which leads to production and release of norepinephrine. Norepinephrine is converted to epinephrine via methyltransferase.

B. Acetaminophen, also known as Tylenol, functions as an analgesic and antipyretic that does not have anticoagulant nor anti-inflammatory properties. Tylenol is safe to use in all ages and during pregnancy.

A. Weight GAIN is common in chronic steroid use. Chronic steroid use comes with many risks including the above as well as hypertension, diabetes mellitus, or peptic ulcers. Ocular effects include PSC cataracts, glaucoma, and risk of secondary infections.

E. Vitamin K reverses the effects of Warfarin. Warfarin, also known as Coumadin, is a Vitamin K antagonist. It prevents clots by interfering with formation of clotting factors that are dependent on Vitamin K.

B/D. TCAs function by increasing levels of serotonin, norepinephrine/epinephrine, and anticholinergic activity. These three functions lead to increased sympathetic output.

C. Natamycin is an antifungal that works by inhibiting ergosterol thereby forming pores in cell walls. This leads to cell death. Recall that Natamycin is NOT a macrolide – a drug class that inhibits the 50s subunit of bacterial ribosomes. Penicillins inhibit transpeptidase.

C. Oseltamivir, also known as Tamiflu, is used in the treatment of Influenza. The remaining options are antifungals. Of note, Natamycin is NOT a Macrolide as the name indicates.

D. Bacitracin prevents bacterial wall synthesis by inhibiting transfer of peptidoglycan into the growing wall. Oxacillin and Cephalexin inhibit transpeptidase. Gentamicin inhibits bacterial protein synthesis by binding 30s subunits of the bacterial ribosome.

D. If a patient is on Warfarin, it is best to prescribe a Penicillin. Cephalosporins may destroy normal intestinal flora thus altering Vitamin K absorption. This may lead to excessive thinning of the blood in conjunction with Warfarin.

A. Simvastatin, also known as Zocor, is one of three cholesterol medications that function by inhibiting HMG-CoA reductase. This enzyme is responsible for production of cholesterol. These medications are first line therapies. Gemfibrozil binds to PPAR-alpha leading to breakdown of VLDL. Cholestyramine binds bile acids in intestines to prevent reabsorption. Isotretinoin is a distractor as it is used in treatment of acne.

B. Levothyroxine, also known as Synthroid, is a synthetic T4 agent that is used for the treatment of Hypothyroidism. Many patients take this medication chronically post-thyroidectomy. Side effects include Hyperthyroidism and IIH.

C. Mannitol, also known as Osmitrol, is a diuretic that affects the entire nephron. It works by increasing plasma osmolarity to draw water out.

A, C: MACI is formed by the anastomosis of the long posterior ciliary and anterior arteries. It is located within the iris stroma and is non-fenestrated.

D. The liver is the only region above that does not drain into the right lymphatic duct.

D. The descending limb of the loop of Henle is permeable to water and impermeable to NaCl. The opposite is true of the ascending limb.

B. In the proximal convoluted tubule, the ATPases drive Na+ out into the interstitial space and K+ in to the proximal convoluted tubule for excretion. Water will follow the Na+

D. IgG is able to cross into the maternal placenta and attack the fetal cells. IgA is the main immune component found in tears. IgE is involved in Type 1 Hypersensitivity reactions which cause the degranulation of mast cells. IgD is found on the plasma membranes of immature B-cells. IgM is the first antibody produced in response to a novel antigen. It is the largest and is capable of producing IgG.

D. Interleukin 2 is released by helper T cells in response to antigen binding. This release, paired with binding of helper T cells to Class II MHC, stimulates the production of more immune factors.

A,D: Thayer-Martin, also known as a chocolate culture agar, is used for culturing and primarily isolating pathogenic Neisseria bacteria, including Neisseria gonorrhoeae and Neisseria meningitidis, as the medium inhibits the growth of most other microorganisms. Gram staining is used to identify bacteria. Sabouraud’s is used in the identification of fungi. Heat treated E. coli plates are used to culture Acanthamoeba.

D. The hypothalamus is responsible for regulating body temperature, hunger, and sleep. The epithalamus contains the pineal gland which regulates circadian rhythms. The thalamus acts as a relay station for sensory input to different cortical regions. The subthalamus and basal ganglia communicate to control muscle movement.

D: Seven – Frontal, Ethmoid, Sphenoid, Lacrimal, Maxilla, Palatine, and Zygomatic

B: Preauricular nodes – the site of palpation in cases of red eye. Medial conjunctival lymphatics travel to the submandibular nodes.

C: The corneal ENDOTHELIUM has the most mitochondria to supply energy to the Na/K pumps that maintain corneal water concentration.

E: Palpebral conjunctiva and within caruncle are two sites of mucous production

D. Although inflammation does cause a widening of meibomian ducts, meibum that has become more viscous will block the further secretions. This blockade leads to acinar atrophy, a primary cause of dry eye.

C. Pterygopalatine innervates the lacrimal gland to stimulate aqueous secretion.

E. All of the above are correct. It is important to understand the general pathways innervation travels to the orbit and adnexa. Try to draw out these pathways with blanks that you can fill in and erase later.

E. The Superior and Inferior ophthalmic veins travel above and below the common tendinous ring, respectively. The remaining options first traverse through the superior orbital fissure and travel through the CTR en route to the globe.

A: The recti muscles are primary facilitators of movement when the eye is turned out at 23 degrees. The obliques are responsible for elevation and depression when the eye is turned in at 51 degrees. Remember O’s to the nose.

B. The CRA has networks within both the Nerve Fiber Layer and the Inner Nuclear Layer. Dot and blot hemes are seen in the OPL as bleeding from INL leaks down layers.

A: Melanopsin is found in the intrinsically photosensitive ganglion cells. These cells are thought to be regulators of the circadian rhythms found in mammals.

A. Vitamin A is the main component of opsins. Vitamin B can be found in all cells and usually depleted in alcoholics. Vitamin C is important in collagen synthesis, antioxidants, wound healing, bone formation, and many other functions. Vitamin D is supplied by the sun and helps in digestion. Vitamin E is an antioxidant found in vapes that in conjunction with nicotine, can increase the likelihood of developing cancer.

D. The INL is not found in the foveola. The six retinal layers in the foveola include: RPE, PRs, ELM, ONL, Henle’s, ILM

B: Microglial cells phagocytose waste and cells in the retina. Alveolar cells are found in lungs. WBCs are found in the bloodstream. Kupffer are phagocytic cells in the liver.

C. Zonula Occludens/Adherens are responsible for tight barriers. Desmosomes maintain structure integrity. Hemidesmosomes are responsible for connecting cells to their basement membranes. Gap junctions serve a role in small ion transport and cell-cell signalling. Keratocytes are cells responsible for structural integrity of the cornea.

Correct Answer d) Pars plana

Explanation:
The zonules (or zonular fibers) are primarily produced by the non-pigmented epithelium of the ciliary body, which is part of the pars plana and pars plicata regions. Most zonular fibers arise from the pars plana and extend forward to attach to the equator of the lens. Some fibers also arise near the valleys between the ciliary processes in the pars plicata.

So, the best answer is pars plana, since that is where the majority of the zonular fibers originate.

Incorrect but educational choices:

a) Pars plicata
This region is part of the ciliary body and contains the ciliary processes. Some zonules do arise here, especially secondary fibers, and they pass between the ciliary processes. However, most zonules originate from the pars plana, which makes pars plana the better choice when both are options.

Board Tip: Questions sometimes ask which region gives rise to the bulk of the zonular fibers, not just any origin. Keep that in mind when similar choices like this appear.

b) Ciliary body stroma
The stroma is the connective tissue core of the ciliary body. It contains blood vessels, nerves, and some muscle, but does not produce zonules. Zonules pass through or near this area, but they are secreted by the non-pigmented epithelial cells, not the stromal tissue.

Board Tip: Be careful with questions that mention “supporting structures.” The stroma supports the ciliary epithelium but does not create zonules. Watch out for similar distractors on anatomy questions.

c) Posterior lens capsule
This is the insertion point for some zonules, not the origin. Zonules attach around the equator of the lens and help suspend and shape it during accommodation, but the posterior capsule does not produce them.

Board Tip: Know the difference between origin and insertion, especially for fibers like zonules or muscles of the eye. These distinctions come up frequently.

e) Pigmented iris epithelium
This is the innermost layer on the posterior surface of the iris. It is not involved in zonule production. It has roles in iris structure and pupil function but does not contribute to suspensory ligaments.

Board Tip: The pigmented layers of the iris and ciliary body often get confused. Remember that zonules come from the ciliary body’s non-pigmented epithelium, not the iris.

Summary:

Correct: d) Pars plana

Best to review further: Differences between pars plana and pars plicata – roles of ciliary body layers

Board strategy: Focus on origin vs. insertion, and what each anatomical layer actually produces

D: Common Tendinous Ring is the site of origin of all four recti muscles. Circle of Zinn is composed of short posterior ciliary arteries. The Spiral of Tillaux involves the insertion of the recti muscles.

C. Cyclobenzaprine, also known as Flexeril, is a muscle relaxant used in treatment of muscle spasms. It works by decreasing somatic motor activity by inhibiting tonic activity of alpha and gamma neurons. Caution as this medication may cause Narrow Angle Glaucoma.

A. Donepezil, also known as Aricept, is used to treat Alzheimer’s. It functions by inhibiting CNS acetylcholinesterase. Adverse effects include cataracts, blur, and ocular irritation. Aricept has been known to reduce intraocular pressure which may rebound with cessation of medication.

D. Methylphenidate, also known as Ritalin, is commonly used in treatment of ADHD, narcolepsy, and depression. Methylphenidate works by increasing release of dopamine. When given in high doses and/or chronically, mydriasis and dry eye disease may occur. Use with caution in patients with Narrow Angles.

B,C,E: Superior limbic keratoconjunctivitis (SLK) is related to FRICTION. Dry eye, thyroid eye disease, and contact lens hypersensitivity are most commonly associated with SLK.

C. Ligneous conjunctivitis is caused by a systemic plasmin deficiency leading to development of thick mucous membranes. Other conditions associated with PAN include viral, inflammatory systemic, and hyperacute bacterial infections.

B. Brinzolamide is a carbonic anhydrase inhibitor that is not associated with follicular conjunctivitis. Recall that chlamydia presents with both follicles AND papillae. Herpes and adenovirus can cause viral conjunctivitis of which follicles are a classic finding. Alphagan, CL solution, and molluscum can all lead to toxic conjunctivitis which presents with follicles.

E. Indirect illumination is used to assess non-opaque corneal lesions by focusing oculars adjacent to the beam of light (i.e EMBD). Sclerotic scatter is used to evaluate the clarity of the cornea. Optic section is used to determine depth (i.e. Van Herick, corneal scar). Conical beam is used to assess anterior chamber for cells and flare. Specular reflection is used to assess the corneal endothelial cells (i.e. Fuchs).

A,D,E: A normal result for phenol red thread test is >10mm in 15 secs, Schirmer 1 test is >10mm in 5 minutes, Schirmer 2 testing (with anesthesia) is >5mm in 5 minutes. Tear osmolarity should be greater than 308 mOsm/L. Tear meniscus is measured under a slit lamp and should be greater than 0.2mm. Tear break up time (TBUT) is evaluated under slit lamp and blue light conditions. The tear film should remain intact for up to 10 secs.

A,E: Either the nasociliary branch of the trigeminal (V1) and/or the facial nerve (VII). The nasociliary nerve is responsible for sensory information from the cornea. Corneal regeneration is reduced as there is little feedback from the corneal nerves that indicate damage. Common causes of damage include HSV, DM, LASIK, contact lens overwear, and chronic corneal injury. The facial nerve can also cause NK due to reduced reflex tearing and inability to close the eyelid leading to chronic damage of ocular surface and further damage to VI. The cotton-swab test is used for aid in diagnosis of NK.

D. The patient is most likely suffering from a recurrent corneal erosion which is caused by poor hemidesmosome attachment. This attachment problem is preceded by corneal abrasion, corneal dystrophies, and/or age-related changes to the basement membrane. Ultraviolet keratopathy is caused by the excessive absorption of short wavelengths – symptoms occur 6-12hrs after exposure. Dry eye is caused by increased levels of MMPs and can cause symptoms at any time of day. Poorly managed blood sugar may lead to neurotrophic keratopathy – patients will have no pain complaints.

D. Progression to late stage K-cone can cause tears in DM, otherwise known as corneal hydrops. Early signs include Fleischer’s ring (an IRON ring that develops early and best visualized with cobalt blue filter), scissor reflex on retinoscopy, and INFERIOR steepening of the cornea on topography. Late signs include Vogt’s striae (VERTICAL folds in the cornea), Munson’s sign (cone appearance of the cornea when patient viewed from above), and hydrops (tears in Descemet’s membrane). Horizontal folds are called Haab striae and are related to glaucoma.

B. The minimum number is 400-700 cells/mm². This range is seen in older patients or those diagnosed with Fuchs’ endothelial dystrophy. From birth, the average range is 3,000-4,000. After 80, that number drops to about 1,000-2,00 cells. Recall that endothelial cells do not regenerate.

E. Disciform keratitis is described as secondary stromal edema in the presence of endotheliitis. The remaining options all impact Bowman’s layer directly. Recall that Bowman’s layer does NOT regenerate.

C. Diabetes is only considered a RELATIVE contraindication. Absolute contraindications include young age, unstable refractive error, unrealistic expectations, k-cone, active herpes, contact lens warpage, connective tissue disease and/or immunocompromised state (including chronic steroid use. Relative contraindications include ocular surface disease (anything related to lid hygiene), fluctuating blood sugar levels, POAG, pregnancy, and/or retinal thinning.

A,C,D: These conditions lead to development of trabeculitis and iritis that reduces aqueous outflow. This reduction in outflow leads to spikes in IOP as high as the 40s-50s. Sarcoidosis may cause inflammation anywhere in the body. Most often, Sarcoidosis leads to bilateral uveitis and may also include posterior or panuveitis. Toxoplasmosis does not often cause anterior uveitis, rather posterior or panuveitis.

C,D: Stellate KPs are unique to Herpes simplex and Fuch’s iridocyclitis. Other options listed here are also considered granulomatous. However, these conditions present with Koeppe (found at pupillary margin) or Busacca nodules (other locations on iris).

A. The most common cause of NVG is a central vein occlusion. Other causes include proliferative diabetic retinopathy, retinal detachments, and ocular ischemic syndrome. All of these conditions cause a release of VEGF. Release of growth factors leads to development of new blood vessels. In NVG, new vessels grow into the drainage angle leading to poor outflow. This change to the angle leads to elevated IOP and development of NVG, aka 90 day glaucoma.

C. Peak incidence of CME post-cataract surgery is 6-10 weeks. The most common cause of CME is post-cataract surgery and is known as Irvine-Gass syndrome. Most cases are resolved with NSAIDs within 6 months. On FA, HYPERfluorescence appears in a petaloid pattern.

A. An S-shaped ptosis is classically associated with dacryoadenitis – inflammation of the lacrimal gland. Dacryoadenitis can occur acutely or chronically. Acute infections present with S-shaped ptosis, pain, redness, and preauricular lymphadenopathy. Acute infections are often bacterial or viral in nature. Chronic infections have a similar set of signs/symptoms, however, to a much lesser degree. Chronic infections are related to inflammatory disorders such as the other answer choices.

E. H. influenzae is the most common cause of simple bacterial conjunctivitis in children. The most common cause in adults is Staph aureus.

D. Negative Jones I and Positive Jones II. Jones I tests the patency of the nasolacrimal system. A Positive Jones I means a Patent system. With NLDO, you would expect a negative Jones I. Jones II is used to attempt to open an obstructed system. Saline is irrigated with pressure into the canal. If a patient is able to gag and taste the saline, you have opened the system – positive Jones II. If patient does not gag/taste and there is retrograde discharge with increased pressure is a negative Jones II. At this point it is important to refer for dacryocystorhinostomy

D. Floppy Eyelid Syndrome is the most likely diagnosis. Snoring is related to obstructive sleep apnea and FES. Patients with FES are known to have issues with elastin – specifically within the tarsal plate with regards to FES. Common signs/symptoms include dryness, papillary conjunctivitis and mild discharge. Recall that dry eye and redness in FES is related to FRICTION.

B. Mueller’s muscle is the culprit. Horner’s is known to affect the sympathetic nervous system. Mueller’s muscle is innervated by sympathetic input and acts to lift the eyelid 2-3mm. This is the reason for the mild ptosis in Horner’s patients.

B. A consequence of congenital aberrant degeneration, the motor branches of the trigeminal nerves will simultaneously communicate with the superior division of the oculomotor nerve which controls the levator.

D. Cholesterol. The condition we are seeing is known as Xanthelasma. The yellow plaques develop over time with elevated cholesterol levels. The patient can be referred for excision/cryotherapy after cholesterol levels are brought back to normal levels.

D. H. influenzae is the most common culprit for cellulitis in children. Staph aureus is the most common cause of cellulitis in adults.

C. The correct order is Inferior rectus, Medial rectus, Superior rectus, Lateral rectus, and then the obliques. The mnemonic for this condition is “IM SLO”.

B. Poliosis is the whitening of eyelashes often caused by chronic eye infections. Madarosis describes a loss of eyelashes. Tylosis is thickening of the lid margin. Trichiasis is an inward turned eyelash. Sudoriferous is a term used to describe a cyst.

D. Verruca is a painless, multi-lobulated lesion with a frondular appearance that may or may not regress over time. It is most believed to be a consequence of HPV. Molluscum is the result of a DNA pox virus that is seen in children or in immunocompromised populations. Contact dermatitis is caused by exposure to allergens. Papillomas are benign “skin tags” that develop spontaneously as we age.

A. Basal cell carcinomas are the most common malignant eye tumors. Next is squamous, then sebaceous, and most rare is malignant melanoma. A nevus is a benign finding on the eyelid that requires monitoring.

C: Ocular Cicatricial pemphigoid is an example of type II hypersensitivity as it involves autoantibodies that target basement membranes. Stevens-Johnson is considered either type 3 or 4 hypersensitivity that affects mucous membranes. Contact dermatitis is a type 4 hypersensitivity reaction as it takes 24-72 hours to develop after exposure. Atopic Keratoconjunctivitis is considered both Type 1 and 4. Phlyctenular keratoconjunctivitis is a type 4 hypersensitivity to staphylococcus.

B, C, D are all findings that elevate the diagnosis from preseptal to orbital cellulitis. In orbital cellulitis, key findings include reduced VA, EOM restrictions, proptosis, and optic nerve involvement. These findings demonstrate the importance of proper treatment of adnexal infections.

A, C, E: The three noted signs are Von graefe, Dalrymple, and Kocher. Von Graefe’s sign is upper eyelid lag during downgaze. Dalrymple’s sign is lid retraction resulting in the “look of surprise”. Kocher’s sign is globe lag compared to lid movement when looking up. Seidel’s sign is aqueous leakage seen in laceration/penetration of the globe. Munson’s sign is the peaked appearance of a cornea from a bird’s eye view of the (looking down from above).

C. Hollenhorst plaques (an example of an emboli) is the most common cause of BRAO. Other causes include GCA, elevated IOP, and other diseases that affect the retina. Calcific emboli are most associated with CRAO. Thrombi are the main cause of BRVOs.

D. NVE with associated preretinal or vitreous hemorrhage is a high risk characteristic. Other high risk characteristics include NVD > ¼ DD within 1 DD of the optic nerve and any NVD or NVE with associated preretinal or vitreous hemorrhage. The other options refer to non-proliferative diabetic retinopathy. Severe NPDR follows the 4-2-1 rule: 4 quadrants with severe hemorrhaging, 2 quadrants of venous beading, and 1 quadrant of IRMA.

B,C,D: CSME, macular edema in the presence of diabetic retinopathy, needs to meet at least one of the three main criteria. The three criteria include: retinal thickening within 1/3DD of the foveal center, hard exudates within ⅓ DD of the foveal center with adjacent retinal thickening, or retinal thickening of at least 1 DD within 1 DD of the foveal center.

A,C,D: The classic triad of signs in RP include bone spicules in the periphery, waxy optic disc pallor, and arterial attenuation. Late stage signs include PSC cataracts, optic disc drusen, macular changes, and progressive loss on visual fields. These are not considered classic findings but rather associated. PSC is responsible for central vision loss in patients with RP.

C. One would expect a high LAG of accommodation as the patient does not have the ability to accommodate. The remaining options are expected findings in AI.

B. 12.5 D. Hofstetter defines three equations: 1. Average Amp of ACC = 18.5 – 0.3(Age), 2. Minimum Amp of Acc = 15 – 0.25(age), 3. Maximum Amp of Acc = 25 – 0.4(age). For this problem, we use equation 2.

A. Fixation disparity is measured under ASSOCIATED conditions. Associated is defined as when two eyes are focused on the same target and fusing images. The other options rely on disassociating the eyes to complete measurements.

E, 4.5 years is roughly when a child should be able to draw and identify a square. Some important shapes to know include: Straight line near the end of 2 years of age, Circle at 3 years, and Triangle near 5 years.

A. Accommodative response is present at birth and reaches maturity at about 3 months of age. It is important to review key ocular motor and visual development milestones.

C. Minus lenses indirectly test NEGATIVE fusional vergence. Adding minus lenses increases accommodation and convergence. In order to maintain images on the fovea,negative fusional vergence is required to overcome the changes. Prisms directly test the direction of their apex.

B. There is an issue with the Superior Oblique of the right eye. To answer this question, you must implement Parks 3-Step. First, we note right hyper in primary gaze which indicates either RIR/RSO or LIO/LSR. Next is the head tilt. The patient is tilted to the right meaning RSR/RSO or LIO/LIR. Last, which gaze is the hyper worse? In this case left gaze which indicates RIO/RSO or LSR/LIR. RSO is the only muscle in all three.

Step-by-step breakdown:
1. Hirschberg Test Purpose:
The Hirschberg test is used to detect ocular misalignment in children. It works by observing the position of the corneal light reflex relative to the center of the pupil.

2. Rule of thumb:
Every 1 mm of reflex displacement = approximately 15 prism diopters (Δ).

If the reflex is nasal to the pupil, the eye is turned outward (exotropia).

If the reflex is temporal to the pupil, the eye is turned inward (esotropia).

3. Apply the findings:

Right eye: reflex is 0.5 mm nasal → ~7.5Δ exotropia

Left eye: reflex is 1.5 mm nasal → ~22.5Δ exotropia

Since the left eye shows a larger deviation, it is the deviating eye, and the right is likely fixating. This means the child has a left exotropia (Left XT) of approximately 22Δ.

Final answer: 22Δ Left XT

Study Tip (Optional “Hint” or “Additional Info” field):
Tips for the NBEO Part I and II:

Memorize: 1 mm displacement ≈ 15Δ

Reflex nasal = exotropia; reflex temporal = esotropia

Use diagrams and photos to practice estimating alignment

Label answer choices clearly (XT = exotropia, ET = esotropia)

Review similar tests: Cover Test, Krimsky, Bruckner, etc.