Ocular Disease

Question 1

What is the difference in etiology between a corneal abrasion and corneal erosion?

Answer 1

Corneal Abrasion: Recall that corneal abrasions, by definition, are ALWAYS from TRAUMA. The most common reason for a corneal abrasion is a FINGERNAIL INJURY. If you have young children you understand why!

Corneal Erosion: Once the abrasion has healed the patient is now at risk for a corneal erosion for the rest of their life. Corneal erosions occur in patients with past corneal abrasions (e.g. trauma) and those with epithelial dystrophies (most commonly EBMD).

Question 2

What is the most common corneal dystrophy?

Answer 2

It’s not even close….. EBMD. So, when we say that corneal erosions happen in patients with epithelial dystrophies, we are almost always referring to EBMD

Question 3

What is Vossius Ring? What does a positive Seidel’s sign indicate?

Answer 3

Vossius ring: after corneal trauma the iris can be pushed posteriorly and can make contact with the lens. As a result a ring of pigment (where the iris contacted the lens) can remain; this is called vossius ring. As a buzz phrase for the exam…. VOSSIUS RING = TRAUMA.

Seidel’s sign: A wound leak is present if Seidel’s sign is positive. If a leak exists,the fluorescein dye will appear as a dark (diluted by the aqueous) stream within the green dye of the tears.

Question 4

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 4

Trauma

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 5

Name the 5 most common reasons for lens subluxation

Answer 5

Trauma
Marfan's Syndrome
Honocystinuria
Ehlers-Danlos Syndrome
Weill-Marhesani Syndrome

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 crepitus?

Answer 8

Repitus refers to the CRackling, rattle-like noise that can occur when two fractures 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 bleading and inflammation; the crackling sign of crepitus also increases during nose blowing.

On the exam…. CREPITUS = orbital wall fracture

Question 9

Which wall is most likely to fracture with trauma?

Answer 9

Floor. More specifically, the posterior-medial portion of the floor. Maxillary bone within the floor is the most likely bone to fracture.

Question 10

thinnest bone in the orbit?

Answer 10

Ethmoid

Question 11

weakest bone in the orbit

Answer 11

maxillary

Question 12

mucomycosis

Answer 12

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

Question 13

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

Answer 13

RCE

Question 14

Which of the folllowing is the most common primary pediatric orbital malignancy?

Answer 14

Recall that primary indicates the tumor began in the orbit.

A) Rhabdomyosarcoma = rapid bone destructing tumor.

Question 15

A) Rhabdomyosarcoma
B) Neuroblastoma
C) Capillary Hemangioma
D) Cavernous Hemangioma

Answer 15

Know em

Question 16

What is the most common orbital tumor in children?

Answer 16

Capillary Hemangioma: benign, look for deprivation ambylopia

Question 17

What is the most common orbital tumor in adults?

Answer 17

Cavernous Hemangioma

Question 18

What is the most common secondary metastatic pediatric tumor?

Answer 18

Neuroblastoma = malignant. The tumor commonly arises from the abdomen, so these patients are in typically in poor systemic health.

Question 19

What condition classically results in bilateral, PERIORBITAL swelling of the eyelids and is typically associated with switching cosmetics, allergic irritants, or recent instillation of eye drops? Hint: onset of symptoms typically occurs within 24-48 hours of irritant exposure).

Answer 19

CONTACT DERMATITIS
Periorbital swelling is associated with contact dermatitis. If they ask a question on boards about a patient recently switching cosmetics (eyeliner for example) with allergic-type symptoms (e.g. conjunctival chemosis), contact dermatitis should be high on your list of differentials.
-Recall that this condition results from a Type-4 DELAYED hypersensitivity reaction (see Hint above).
-Remember, conjunctival chemosis is a phrase you should immediately associate with ALLERGY on the exam.

Question 20

What is ankyloblepharon? Name a condition where this sign is found?

Answer 20

ANKYLOBLEPHARON and SYMBLEPHARON are the two main signs found in PEMPHIGOID, a condition that is most common in females 60 yrs and older.

Ankyloblepharon occurs when the outer eyelids become stuck together. Symblepharon occurs when the bulbar and palpebral conjunctiva become stuck together.

Recall that pemphigoid is an idiopathic condition that attacks MUCOUS MEMBRANES; the eye is a natural place for attack considering the mucous surface of the orbital and palpebral conjunctiva.

Question 21

What are the two main signs found in pemphigoid?

Answer 21

Ankyloblepharon and symblepharon.

Question 22

What are the three ocular conditions associated with mucous membrane damage?

Answer 22

1) Pemphigoid
2) Bechet’s Disease (mouth ulcers with uveitis)
3) Steven Johnson’s Syndrome

Question 23

What is the difference between an external hordeolum and an internal hordeolum?

Answer 23

External hordeolums affect glands of Zeis and/or Moll.

Internal hordeolums affect meibomian glands.

Question 24

What is the function of the glands of Zeis?

Answer 24

Lubrication of the eyelashes

Question 25

What is the function of the glands of Moll?

Answer 25

sweat glands

Question 26

all contributors to the lipid layer

Answer 26

MG, Zeis, Moll. MG#1

Question 27

MC Etiology of ectropian

Answer 27

Involutional

Involutional indicates that the condition is AGE-RELATED. Remember that the Facial Nerve (CN VII) is responsible for innervating the orbicularis oculi, the muscle that allows for eyelid closure. Bell’s Palsy is a condition that affects the lower portion of CN VII; poor innervation to this musculature leads to ectropion and subsequent corneal exposure issues.

Question 28

LC of infectious blindness worldwide

Answer 28

Trachoma

Question 29

What causes trachoma blindness

Answer 29

entropian, K scarring

Question 30

What do Blepharospasm and Myokymia have in common?

Answer 30

Both conditions affect ORBICULARIS OCULI musculature. Myokymia ONLY affects the orbicularis oculi; Blepharospam affects three muscles - the orbicularis oculi, procerus and corrugator musculature.
Recall that BLEPHAROSPASM = BILATERAL TWITCHING that progresses to eyelid closure.
MYOKYMIA = UNILATERAL TWITCHING.

You will have lots of patients in clinical practice who report twitching of the eyelid. Immediately ask if the twitching is unilateral or bilateral. I have never heard a patient say bilateral (b/c blepharospasm is extremely rare!). For myokymia, ask about the following… all of which are common causes of the condition:

Increase in caffeine intake?
Increase in stress at home and/or work?
Less sleep as of late?