Ocular Disease 1

Question 1

When is arcus NOT normal (give two scenarios)?

Answer 1

Patients under 40 years old – lipid profile warranted in these patients.
Unilateral arcus – this is associated with carotid artery disease

Question 2

What condition results in the classic patient complaint of pain in the morning after opening the eyes?

Answer 2

Recurrent corneal erosion

Question 3

What is mucormycosis?

Answer 3

A life-threatening FUNGAL infection that can occur in DIABETICS and/or IMMUNOCOMPROMISED patients with orbital cellulitis.

Question 4

What is crepitus? What is it associated with?

Answer 4

CRepitus refers to the CRackling, rattle-like noise that can occur when two fractured bones rub against one another. After an orbital wall fracture patients should be told NOT to blow their nose for at least 48 hrs following the incident. Blowing the nose increases pressure within the area of trauma and can further bleeding and inflammation; the crackling sign of crepitus also increases during nose blowing.

Question 5

Which wall of the orbit is most likely to fracture with trauma?

A. Roof
B. Lateral wall
C. Medial wall
D. Floor

Answer 5

D. Floor. More specifically, the posterior-medial portion of the floor. Maxillary bone within the floor is the most likely bone to fracture. Recall that the ethmoid bone is the thinnest bone in the orbit, the maxillary bone the weakest.

Question 6

What is a hyphema? What is the most common cause of non-trauma related hyphemas?

Answer 6

Hyphema is blood in the anterior chamber. Recall that the blood in a hyphema is from the iris and/or ciliary body.

NSAID (e.g. aspirin, ibuprofen) use, blood clotting disorder (e.g. sickle cell anemia) is often the cause in a non-trauma related hyphema.

Question 7

Why would a B-scan be indicated in a patient with an 8-ball hyphema?

Answer 7

8-ball hyphema means that the entire anterior chamber is full of blood. Thus, no view of the posterior chamber would be possible. You should associate the use of B-scan with two main scenarios

To view posterior segment when media opacities (e.g. dense cataracts) or other pathology (vitreous hemorrhage, for example) do not allow an adequate view.
To aid in diagnosis of optic nerve drusen.

Remember, A-scans are used to measure axial length; a popular use is for calculation of IOL power for cataract surgery. B-scan for blocked fundus and ONH drusen.

Question 8

What is the most common reason for lens subluxation?

A) Marfan’s syndrome
B) Trauma
C) Homocystinuria
D) Ehlers-Danlos Syndrome
E) Weill-Marhesani Syndrome

Answer 8

B. Trauma is the No. 1 cause of lens subluxation. Make sure you know the other options listed above…. all of those options can cause lens subluxation. Most of you would correctly state that Marfan’s Syndrome is a common cause, but be sure to take a minute or two to memorize the other three conditions that you should also associate with this complication.

Question 9

Which of the following peripheral corneal findings is the most common?

A. Arcus
B. Staphylococcal marginal keratitis
C. Moorens Ulcer
D. Salzmanns nodular degeneration
E. Terriens marginal degeneration

Answer 9

A. Arcus is the most common peripheral corneal opacity and is associated with aging and high-cholesterol.

Question 10

Which of the following tests can be used to evaluate syphilis? (Pick 6)

1. Purified protein derivative (PPD) test
2. Enzyme immunoassay (EIA) test
3. Rapid plasma reagin (RPR) test
4. Venereal disease research laboratory (VDRL) test
5. Treponema pallidum particle agglutination assay (TPPA)
6. Darkfield microscopy
7. Microhemagglutination assay (MHA-TP)
8. Antinuclear Antibody (ANA) test

Answer 10

Correct Answers = 2,3,4,5,6,7.

(PPD testing is for tuberculosis. ANA testing is for autoimmune diseases.)

Does this surprise you that this many tests are available to evaluate syphilis? I wrote this question just to make sure that you did NOT merely memorize the most common tests for syphilis (e.g.RPR, VDRL, and FTA-ABS) and miss a potential detailed NBEO question that expected you to know more.

A simplistic overview of syphilis evaluation can be thought of as the following:

Screening Tests: RPR, VDRL, EIA
Diagnostic Tests: FTA-ABS, TPPA, Darkfield Microscopy, MHA-TP

Question 11

Which of the extraocular muscles in a thyroid eye disease (TED) patient is most likely to have the highest concentration of glycosaminoglycans (GAGS)?

1. Lateral rectus
2. Medial rectus
3. Inferior rectus
4. Superior rectus

Answer 11

Correct Answer = INFERIOR RECTUS. Another way I could have asked this question would have been to ask which EOM swells first in a TED patient.

Recall that EOM swelling is a significant concern in patients with TED; increased muscle swelling (water follows GAGS) can lead to compression of the EOM’s against the optic nerve, leading to nerve damage and an APD. The order of EOM swelling in TED is typically the following — INFERIOR RECTUS, MEDIAL RECTUS, SUPERIOR RECTUS, LATERAL RECTUS, OBLIQUES. Some students prefer the pneumonic: “I’m slow,” which is written as “IMSLO” (Inferior rectus, Medial rectus, Superior rectus, Lateral rectus, Obliques) as the order in which the EOM swelling occurs.

Exposure keratopathy and superior limbic keratoconjunctivitis (SLK), are always a concern with these patients as well, but permanent optic nerve damage from EOM compression tops my list of concerns in these patients.

Kocher sign (globe lags behind the movement of the upper eyelid in upward gaze), Dalrymple’s sign (stare appearance) and Von Graefe’s sign (lid lag during downgaze) are the three major signs to know for this condition.

Recall that exposure keratopathy = corneal issue secondary to EYELID problem (e.g. TED, Bell’s palsy, nocturnal lagophthalmos).

Question 12

Which of the following is TRUE regarding thyroid eye disease? (Pick 3)

1. Women are more commonly affected
2. Cigarette smoking is a risk factor
3. Myasthenia Gravis is correlated with the condition
4. Most common in 3rd to 4th decades of life

Answer 12

Correct Answers = 1,2,3

Thyroid eye disease (TED) is MOST commonly associated with 4th to 5th decade of life, NOT 3rd to 4th. Carefully look at the other answers and be sure to know those facts, because all are true regarding TED.

Other Clinical Pearls about TED….
-The No.1 cause of unilateral OR bilateral proptosis in a middle-aged patient is thyroid eye disease. Most of us would have chosen TED as the No.1 cause of bilateral proptosis, but REMEMBER… it is also the leading cause of unilateral as well! When you have an older patient with proptosis, a tumor should be high on your list of differentials (especially lymphoma). I remember in residency having a 80 yr old male with unilateral proptosis and immediately my residency director told me that we were likely dealing with a lymphoma. I couldn’t believe how quickly he came to that conclusion (he had several similar cases in the past); we ordered a CT scan and he was correct.

• Thyroid eye disease causes PAINLESS proptosis in young patients. Other less common causes of painless proptosis in young to middle-age patients would be schwannomas and meningiomas.
• Orbital pseudotumor causes PAINFUL proptosis in young to middle-age patients.

Question 13

Which of the following is correlated with Basal Cell Carcinoma? (Pick 3)

1. Rodent ulcer
2. 2nd most common eyelid cancer
3. Actinic keratosis
4. Telangiectasia
5. Stratum spinosum
6. Often misdiagnosed as a “recurrent chalazion”
7. Stratum Basale

Answer 13

Correct Answers = 1,4,7

The classic appearance of BCC is a shiny, firm, pearly nodule with superficial telangiectasia. If not recognized or treated at early stage, BCC can progress to a “rodent ulcer” appearance (late stage). BCC occurs in the stratum basale layer of the skin. BCC is the most common eyelid cancer – it is 40-50x’s more common than SCC.

Recall that sebaceous gland carcinoma is often mistaken for a recurrent chalazion. To be more specific, some patients have a sebaceous gland carcinoma that is initially mistaken for a chalazion. They have surgery to remove the lesion and instead of it being permanently removed (which is what is expected with chalazion surgery) the lesion returns. This can be mistaken as another chalazion, but appropriate evaluation with biopsy would reveal the cancer.

Question 14

Which of the following is TRUE regarding Thygeson’s superficial punctate keratopathy? (Pick 4)

1. Most common in 2nd to 3rd decade
2. Rare type of chronic keratitis with an unknown etiology
3. Bilateral, “crumb-like” intraepithelial opacities
4. Occurs in a white, quiet issue with no anterior chamber reaction or conjunctival injection
5. Intense fluorescein staining is common in the areas of the corneal lesions

Answer 14

Correct Answers = 1,2,3,4

Classic presentation of Thygeson’s includes bilateral (90%), small, multiple, asymmetric gray-white INTRAEPITHELIAL clusters (“crumb-like in appearance) of corneal lesions (typically central in location). These findings are typically in a white, quiet eye with no conjunctival injection or anterior chamber reaction.

Several conditions result in subepithelial opacities, but Thygeson’s is unique in that it results in intraepithelial opacities.

Question 15

Why does Dalrymple’s sign sign occur in a thyroid eye disease (TED) patient?

Answer 15

Recall that Dalrymple’s sign refers to the classic stare appearance seen in TED patients.

Correct Answer = EOM swelling posterior to the globe pushing the eye anterior in location AND overactive sympathetic nervous system resulting in eyelid retraction from innervation to Muller’s muscle.

Why does TED result in an overactive sympathetic nervous system and what type of symptoms, in what gender patient, would you expect for these patients?

Correct Answer = TED is an autoimmune disorder that creates a molecule that acts like thyroid stimulating hormone (TSH). This TSH mimic acts on the thyroid gland, over and over, and results in the production of too much T3 and T4; the sympathetic effects of these hormones result in tachycardia (very common complaint), hair loss, heat intolerance, and weight loss. TED affects women (8:1) more than men.

Question 16

Why does a patient with a recurrent corneal erosion often report pain in the morning after opening their eyes?

Answer 16

Correct Answer = opening the eyes pulls epithelial cells off of the basement membrane.

Recall that corneal abrasions are often the culprit for later development of recurrent corneal erosions. The concept to understand is what type of initial corneal abrasion occurred. If the initial defect was only a mild epithelial defect (and no subsequent damage to the basement membrane), the epithelium will regenerate within 24-48 hours and the risk of future corneal erosion is low.

However, if the initial abrasion resulted in trauma to the basement membrane (such as in fingernail, paper cuts, and other cutting-type insults), an 8 week healing period is required for the basement membrane to fully regenerate and connections to overlying basal cells to occur. These patients are much more likely to develop a recurrent corneal erosion in the future, especially in the 8 week period immediately following the healing of the abrasion.
Understanding this is awesome for your clinical knowledge because it will help you understand treatment approaches for RCEs that involved BM damage at a very high level. Knowing the basic anatomy and understanding the importance of the 8 week healing window allows you to properly explain the pathophysiology to the patient, which in turn motivates them to be compliant with your treatment regimen, which decreases their risk (after the abrasion) for a RCE.

In the above discussion, I mentioned that it takes 8 weeks for the basement membrane to heal and for connections to overlying basal cells to regenerate.

Question 17

What types of connections are present between the corneal BM and basal cells?

Answer 17

Correct Answer = Hemidesmosomes. Remember from the histology chapter that this is the only type of cell junction that does NOT connect cell to cell. Hemidesmosomes always connect BM to CELLS.

Question 18

Which bacterial conjunctivitis is characterized by ocular findings characteristic of viral etiology?

Answer 18

Correct Answer = GONOCOCCAL CONJUNCTIVITIS

Two key signs in gonococcal conjunctivitis are unusual for a bacterial conjunctivitis, they include:

1) Marked preauricular lymphadenopathy
2) Pseudomembranes

Also, remember that gonorrhea classically causes HYPERACUTE signs and symptoms. For example, a patient with viral conjunctivitis will commonly report a red eye that has gradually come on over the past couple of days. A patient with Gonorrhea, on the other hand, will often be able to tell you the exact hour that the signs and symptoms started. Remember that Gonorrhea causes PURULENT discharge and these patients often have pain during urination.

Question 19

What does the gram stain for N. gonorrhea reveal?

Answer 19

Correct Answer = GRAM(-) INTRACELLULAR DIPLOCOCCI.

Question 20

Describe the classic clinical findings for a chlamydia patient.

Answer 20

Correct Answer = Unilateral red eye of chronic duration (often 3 months or longer) with GIANT follicles in the inferior fornices. In a young patient with chronic red eyes, dry eye is the most likely culprit; however, chlamydia should also be on your list of differentials!

So, remember…. Chlamydia is Chronic…. Gonorrhea is Acute (HYPERACUTE to be more specific)

Question 21

Why are papillae red and follicles white? Name two clinical scenarios where you would expect to see papillae and two clinical scenarios where you would expect to see follicles.

Answer 21

Papillae are RED because their core consists of a central vessel (vascular core).
Follicles are WHITE because their core consists of lymphocytes and macrophages (avascular core).
Correct Answers =

Follicles are specific to toxic, viral and chlamydia. I would know these three conditions verbatum!…. toxic, viral, chlamydia….. toxic, viral, chlamydia… chant it over and over!
Papillae are non-specific, but often found in allergic and bacterial infections. One student told me they remember this is pABillae = Allergic, Bacterial

Question 22

What two conditions are associated with giant papillae?

Answer 22

Correct Answers = GPC and VKC (called “Cobblestone papillae”)

Question 23

Why does a lesion on the tip of the nose (Hutchinson’s sign) denote likely ophthalmic involvement in a Herpes Zoster patient?

Answer 23

Correct Answer = The NASOCILIARY DIVISON branch of V1 provides sensory innervation to the side of the NOSE, to the CORNEA and to the iris. Since this same branch innervates both (cornea and nose) structures, a lesion in one area denotes likely involvement in the other as well.

Question 24

Which of the following conditions affect Descemet’s membrane? (Pick 2)

1. Hydrops
2. Pterygium
3. EBMD
4. Haab’s striae
5. Crocodile Shagreen
6. Band keratopathy

Answer 24

Correct Answers = 1,4

Recall that hydrops is a rupturing of Descemet’s that can occur in keratoconus patients. Haab’s striae are folds in Descemet’s membrane that occur in CONGENITAL GLAUCOMA.

Question 25

Describe the pathophysiology and most likely associated systemic conditions with Central Retinal Vein Occlusions (CRVO’s). Why is primary open angle glaucoma (POAG) the most common ocular disease associated with CRVO’s?

Answer 25

Correct Answer = This is a complex question. In most cases, a CRVO results from an artery compressing the central retinal vein — the artery compresses the vein because of HTN (most common) and DM, and high cholesterol (contributes to hardening of the arteries). As you could imagine, an artery compressing a vein leads to poor blood flow in the vein, which results in turbulent blood flow and a subsequent thrombus (localized blood clot).

Correct Answer = Did you remember that the optic nerve is literally comprised of millions of individual axons of ganglion cells? Good. Did you remember that the central retinal vein gains access to the retina by traveling through the optic nerve? Sure you did, because when you look at the optic nerve in clinic you always see the central retinal vein on the surface of the disc as it begins to branch into different segments. In most eyes, as the central retinal vein travels through the optic nerve (as it approaches the optic disc) it is tightly surrounded within the optic nerve by the axons of ganglion cells. You could imagine, however, in an optic nerve with unhealthy axons, that the central retinal vein would not be tightly surrounded, and thus the vein could actually cork on itself (similar to a water hose). This central retinal vein corking AND/OR the artery compressing on a vein (described above) is what occurs in eyes with CRVO’s. Isn’t that interesting? You might be asking what this has to do with POAG? Well, vein corking results from poor optic nerve architecture (unhealthy ganglion cell axons), correct? POAG also results from damage to ganglion cell axons. Here is the clinical relevance…. If you have a patient with a CRVO in the right eye and vision is 20/400. For the rest of their life, as you follow their good eye (OS), you need to assume that vein corking could have been the culprit in the right eye AND that that the left eye could have the exact same nerve architecture, which could damage more easily with increased IOP. In residency we were trained to constantly write this concern in the patient’s chart (I”ll use the scenario above as the example for the following:)
OD: 20/400 secondary to CRVO
OS: 20/15 – watch for POAG, no glaucoma yet!

By stating “no glaucoma yet”, this serves a constant reminder to watch the good eye for POAG development. I loved how much this was stressed in my education because it would have been too easy to constantly focus on the 20/400 eye and simply forget that the other eye is at risk for POAG! BTW, this example is likely too specific of information for a Part 1 examination. However, if you followed the information above, this is awesome clinical knowledge to have moving forward in your education!

Question 26

Describe the appearance of the retina several weeks after a Central Retinal Artery Occlusion (CRAO).

Answer 26

Correct Answer = At first glance, the retina will look completely normal

In residency, I was told that I would likely have a patient in the future who was an older male or female who would enter my office with complaints of severe vision loss in one eye AND upon dilated evaluation, I would not be able to find anything abnormal in the eye. My residency director was correct. This scenario has happened to me many times in practice….. BUT, he told me what to watch for and I haven’t missed it yet. The diagnosis is a CRAO.

The retina will look absolutely normal EXCEPT for the ARTERIAL vessels, which will appear ATTENUATED. If you look closely with your BIO at the optic disc you will notice a significant difference in arterial vessel size as you compare between the eyes. This is an awesome clinical tip AND you WILL notice the difference when you do this clinically.

Remember, in these cases the patient will typically have severe vision loss and an APD and you will know that something is seriously wrong. After dilation, upon fundus evaluation, you might initially be confused as to why the vision is so poor (b/c the eye looks relatively normal), but upon comparison of vessel size, with BIO, you won’t miss it.

Recall that a fresh CRAO will have superficial WHITENING of the inner retinal layers. As weeks progress, the retinal tissue dies (whiteness goes away) and then appears to look normal.

Question 27

Which of the following organisms is MOST commonly associated with the formation of "true" membranous conjunctivitis?
A. Corynebacterium diphtheriae
B. Streptococcus pyogenes
C. Neisseria meningitidis. 
D. Staphylococcus aureus
E. Haemophilus influenzae

Answer 27

A. Explanation - The formation of a true membrane in cases of acute membranous conjunctivitis is most commonly associated with a Corynebacterium diphtheria infection. Several other organisms can also cause membranous conjunctivitis (Strep hemolyticus, Strep pneumonia, N. gonorrhoeae, S. aureus, H. aegypticus, E. coli, adenoviruses, and herpes simplex); however, membranes are more or less synonymous with diphtheric conjunctivitis.

The difference between a true membrane and pseudomembrane is that in a pseudomembrane, the coagulum is deposited on the surface of the epithelium, while true membranes infiltrate the superficial layers of the conjunctival epithelium. A pseudomembrane can typically be easily peeled off, leaving the epithelium intact; while attempted removal of a true membrane can lead to bleeding and tearing of the conjunctival epithelium.