NBEO PART 1 CORRECT EXAMS SCRIPT
QUESTIONS AND ANSWERS SURE A+
✔✔Numerous reports have suggested that increased tear film osmolarity is a key
consequence in dry eye. Although osmolarity is not easily measured in the clinical
setting, tear osmolarity increases in most dry eye sub-types due to which of the
following processes?
The lipid layer is altered in most dry eye states, leading to ion pairing
Decreased capillary exchange leads to ionic bonding
Patients with dry eye tend to blink less than normals, leading to increased evaporation
Reactive oxygen species are increased in the tears of most dry eye sub-types; this
increases osmolarity
In aqueous tear deficiency, the lacrimal gland produces more ionic species
Loss of tear stability induces an increased evaporation rate, leading to increased
osmolarity - ✔✔Tear instability leads to greater evaporation and higher osmolarity
through a mechanism of concentration of the remaining tears, since only the aqueous
tear portion evaporates rather than the ionic species. Several studies have indicated
that normal tear osmolarity is less than or equal to 300 Osm/L, with values exceeding
308 Osm/L indicating increased osmolarity. As a single measure, tear osmolarity has
recently been found to correlate the best (r squared 0.55) to dry eye severity of several
clinical tests in a large, multi-center study (Sullivan et al., IOVS 51:6125-6130, 2010).
,✔✔Many skin anomalies may mimic malignant lesions. Which of the following skin
conditions has the HIGHEST risk of becoming malignant?
Cutaneous horn
Papilloma
Actinic keratosis
Seborrhoeic keratosis - ✔✔Actinic keratosis is a precursor to squamous cell carcinoma
and appears as scaly, dry skin that does not heal. People with skin that is of lighter
pigmentation along with excessive exposure to ultraviolet light tend to be most at risk for
development of this condition.
Papillomas may take on various forms and may be viral or non-viral in origin. They can
commonly be found on the eyelids or surrounding orbital skin. Viral warts tend to grow
at an accelerated rate while non-viral papillomas are fairly slow to grow. Papillomas can
mimic neoplastic growths so be sure to rule this out while watching carefully for color
change, ulceration, lash loss, bleeding, and vascularization.
Cutaneous horns or tags are also benign and are likely a form of papilloma but appear
to involve more keratin. Treatment is similar to that of a papilloma.
Seborrhoeic keratosis is more commonly seen in middle-aged and elderly persons. This
benign, epidermal growth is quite superficial and does not extend into the dermis. It
appears like a brown plaque that has been stuck onto someone's skin. The borders are
very distinct and there may be some elevation. The lesions may be removed if the
patient is concerned about cosmesis.
✔✔In addition to the meibomian glands which other accessory glands secrete oil?
Zeiss and Moll
Moll and Krause
Zeiss and Wolfring
Wolfring and Krause - ✔✔The glands of Zeiss and Moll are accessory oil glands located
on the lid margins adjacent to the base of the lash follicles. The lipid layer of the tear
film is superficial and as such it is exposed to the environment protecting the aqueous
layer from evaporation.
The glands of Wolfring and Krause are located deep in the fornix of the eyelids and
serve to secrete a portion of the aqueous layer of the tear film.
✔✔Dacryoadenitis refers to an inflammation or infection of which of the following ocular
structures?
The nasolacrimal sac
The lacrimal sac
The lacrimal gland
The puncta - ✔✔Dacryoadenitis describes inflammation of the lacrimal gland, generally
due to infection. The swelling is categorized as either chronic or acute. Acute
presentations appear more commonly as a unilateral swelling of the upper eyelid, along
with pain, excessive lacrimation, probable ipsilateral lymphadenopathy, and potential
,proptosis. If the condition is bilateral it is likely due to a systemic infection. Chronic
dacryoadenitis is generally bilateral and presents with hard masses that are palpable at
the location of the lacrimal gland. This form is often painless and caused by
inflammatory diseases such as Grave's, Sjogren's, or sarcoidosis. The chronic type
warrants further investigation in order to rule out a lacrimal gland tumor.
✔✔Chronic blepharitis, if left untreated, can cause which of the following structural
changes to the anterior ocular segment?
Hypertelorism
Distichiasis
Tristichiasis
Madarosis - ✔✔Blepharitis is a condition caused by pathogens, usually of
Staphylococcus origin, that colonize along the eyelid margins. The bacteria produce
exotoxins which take the form of flakes and are generally seen along the base of the
eyelashes. Unfortunately, this condition is chronic but will wax and wane in its
presentation. Long-term complications include madarosis (missing lashes), trichiasis,
neovascularization of the eyelid margin, keratitis, erythema, phlyctenule formation and
infiltrates. Patients may complain of dry, irritated eyes, stinging, pain, itching, frequent
eye infections, foreign body sensation, and decreased acuity (if there is corneal
involvement). Treatment includes eye lid scrubs, antibiotic ointments and sometimes
transient topical steroid use to decrease lid inflammation (usually used in conjunction
with a topical antibiotic). Occasionally oral antibiotics are prescribed, especially in the
event of poor compliance.
Distichiasis is a rare congenital phenomenon marked by an absence of meibomian
glands. In the place of the meibomian glands is an extra row of eyelashes.
Hypertelorism is a term used to describe the incidence in which the orbits are located
quite far apart. This generally occurs along with other congenital cranium anomalies.
Tristichiasis is a very rare occurrence in which a person possesses three rows of
eyelashes.
✔✔Ptosis can be caused by dysfunction or damage to which of the following muscles?
Inferior rectus
Muscle of Horner
Superior tarsal muscle (muscle of Muller)
Pars ciliaris (Riolan's muscle) - ✔✔Ptosis is a condition in which the upper eyelid sags.
It can be caused by dysfunction of either the superior palpebral levator or the superior
tarsal muscle (muscle of Muller). Because the levator is the major muscle responsible
for raising the upper eyelid, ptosis from levator damage is often more severe then ptosis
from dysfunction of the muscle of Muller.
The muscle of Horner (also known as the pars lacrimalis) is part of the palpebral portion
of the orbicularis oculi. The fibers for the muscle of Horner come from the lacrimal crest
and encircle the lacrimal canaliculi. This assists the flow of tears into the nasolacrimal
, drainage system when the orbicularis oculi contracts to close the eye. The muscle of
Riolan (also known as the pars ciliaris) is another section of the palpebral portion of the
orbicularis oculi; it lies near the lid margin to maintain the margins next to the globe. The
orbicularis oculi is the major muscle responsible for closing the eyelids.
✔✔Tear volume in a normal, healthy, young adult measures approximately between
which of the following values?
13.0-16.0 microliters
6.0-8.0 microliters
17.0-20.0 microliters
2.0-5.0 microliters
9.0-12.0 - ✔✔Tear volume has been measured by several methods to be approximately
6-7 microliters in normal individuals, with lesser values occurring in conditions of
aqueous tear deficiency. This has implications for drug delivery, since the normal
ophthalmic drop volume varies between 25 and 50 microliters, effectively overwhelming
the native tear value upon instillation.
✔✔The lymphatic system serves many important roles in the human body. The lateral
portion of the eyelid lymphatics drain into which of the following structures?
The puncta
The conjunctiva
The submandibular lymph node
The pre-auricular lymph node - ✔✔The lateral 2/3 of the upper lid and the lateral 1/3 of
the lower lid lymphatics drain into the pre-auricular lymph node located directly in front
of the ear. The medial 1/3 of the upper eye lid and the medial 2/3 of the lower lid
lymphatics drain into the submandibular node located just under the jaw-line. Therefore,
it is very important to evaluate these two nodes separately, especially when a condition
of viral etiology is suspected.
✔✔A 2.5x Galilean telescope has a -25D ocular lens. When focused for infinity, what is
the length of the telescope?
5 cm
4 cm
6 cm
10 cm
14 cm - ✔✔M = -Doc/Dobj where Doc=power ocular; Dobj= power objective; t=
separation of lenses
2.5= - (-)25/Dobj
Dobj= 10D
t= f'obj + f'oc
f'obj=1/10D = 0.10 m
f'oc = 1/-25D = 0.04 m
t=0.10 + -0.04 = 0.06 m or 6 cm
QUESTIONS AND ANSWERS SURE A+
✔✔Numerous reports have suggested that increased tear film osmolarity is a key
consequence in dry eye. Although osmolarity is not easily measured in the clinical
setting, tear osmolarity increases in most dry eye sub-types due to which of the
following processes?
The lipid layer is altered in most dry eye states, leading to ion pairing
Decreased capillary exchange leads to ionic bonding
Patients with dry eye tend to blink less than normals, leading to increased evaporation
Reactive oxygen species are increased in the tears of most dry eye sub-types; this
increases osmolarity
In aqueous tear deficiency, the lacrimal gland produces more ionic species
Loss of tear stability induces an increased evaporation rate, leading to increased
osmolarity - ✔✔Tear instability leads to greater evaporation and higher osmolarity
through a mechanism of concentration of the remaining tears, since only the aqueous
tear portion evaporates rather than the ionic species. Several studies have indicated
that normal tear osmolarity is less than or equal to 300 Osm/L, with values exceeding
308 Osm/L indicating increased osmolarity. As a single measure, tear osmolarity has
recently been found to correlate the best (r squared 0.55) to dry eye severity of several
clinical tests in a large, multi-center study (Sullivan et al., IOVS 51:6125-6130, 2010).
,✔✔Many skin anomalies may mimic malignant lesions. Which of the following skin
conditions has the HIGHEST risk of becoming malignant?
Cutaneous horn
Papilloma
Actinic keratosis
Seborrhoeic keratosis - ✔✔Actinic keratosis is a precursor to squamous cell carcinoma
and appears as scaly, dry skin that does not heal. People with skin that is of lighter
pigmentation along with excessive exposure to ultraviolet light tend to be most at risk for
development of this condition.
Papillomas may take on various forms and may be viral or non-viral in origin. They can
commonly be found on the eyelids or surrounding orbital skin. Viral warts tend to grow
at an accelerated rate while non-viral papillomas are fairly slow to grow. Papillomas can
mimic neoplastic growths so be sure to rule this out while watching carefully for color
change, ulceration, lash loss, bleeding, and vascularization.
Cutaneous horns or tags are also benign and are likely a form of papilloma but appear
to involve more keratin. Treatment is similar to that of a papilloma.
Seborrhoeic keratosis is more commonly seen in middle-aged and elderly persons. This
benign, epidermal growth is quite superficial and does not extend into the dermis. It
appears like a brown plaque that has been stuck onto someone's skin. The borders are
very distinct and there may be some elevation. The lesions may be removed if the
patient is concerned about cosmesis.
✔✔In addition to the meibomian glands which other accessory glands secrete oil?
Zeiss and Moll
Moll and Krause
Zeiss and Wolfring
Wolfring and Krause - ✔✔The glands of Zeiss and Moll are accessory oil glands located
on the lid margins adjacent to the base of the lash follicles. The lipid layer of the tear
film is superficial and as such it is exposed to the environment protecting the aqueous
layer from evaporation.
The glands of Wolfring and Krause are located deep in the fornix of the eyelids and
serve to secrete a portion of the aqueous layer of the tear film.
✔✔Dacryoadenitis refers to an inflammation or infection of which of the following ocular
structures?
The nasolacrimal sac
The lacrimal sac
The lacrimal gland
The puncta - ✔✔Dacryoadenitis describes inflammation of the lacrimal gland, generally
due to infection. The swelling is categorized as either chronic or acute. Acute
presentations appear more commonly as a unilateral swelling of the upper eyelid, along
with pain, excessive lacrimation, probable ipsilateral lymphadenopathy, and potential
,proptosis. If the condition is bilateral it is likely due to a systemic infection. Chronic
dacryoadenitis is generally bilateral and presents with hard masses that are palpable at
the location of the lacrimal gland. This form is often painless and caused by
inflammatory diseases such as Grave's, Sjogren's, or sarcoidosis. The chronic type
warrants further investigation in order to rule out a lacrimal gland tumor.
✔✔Chronic blepharitis, if left untreated, can cause which of the following structural
changes to the anterior ocular segment?
Hypertelorism
Distichiasis
Tristichiasis
Madarosis - ✔✔Blepharitis is a condition caused by pathogens, usually of
Staphylococcus origin, that colonize along the eyelid margins. The bacteria produce
exotoxins which take the form of flakes and are generally seen along the base of the
eyelashes. Unfortunately, this condition is chronic but will wax and wane in its
presentation. Long-term complications include madarosis (missing lashes), trichiasis,
neovascularization of the eyelid margin, keratitis, erythema, phlyctenule formation and
infiltrates. Patients may complain of dry, irritated eyes, stinging, pain, itching, frequent
eye infections, foreign body sensation, and decreased acuity (if there is corneal
involvement). Treatment includes eye lid scrubs, antibiotic ointments and sometimes
transient topical steroid use to decrease lid inflammation (usually used in conjunction
with a topical antibiotic). Occasionally oral antibiotics are prescribed, especially in the
event of poor compliance.
Distichiasis is a rare congenital phenomenon marked by an absence of meibomian
glands. In the place of the meibomian glands is an extra row of eyelashes.
Hypertelorism is a term used to describe the incidence in which the orbits are located
quite far apart. This generally occurs along with other congenital cranium anomalies.
Tristichiasis is a very rare occurrence in which a person possesses three rows of
eyelashes.
✔✔Ptosis can be caused by dysfunction or damage to which of the following muscles?
Inferior rectus
Muscle of Horner
Superior tarsal muscle (muscle of Muller)
Pars ciliaris (Riolan's muscle) - ✔✔Ptosis is a condition in which the upper eyelid sags.
It can be caused by dysfunction of either the superior palpebral levator or the superior
tarsal muscle (muscle of Muller). Because the levator is the major muscle responsible
for raising the upper eyelid, ptosis from levator damage is often more severe then ptosis
from dysfunction of the muscle of Muller.
The muscle of Horner (also known as the pars lacrimalis) is part of the palpebral portion
of the orbicularis oculi. The fibers for the muscle of Horner come from the lacrimal crest
and encircle the lacrimal canaliculi. This assists the flow of tears into the nasolacrimal
, drainage system when the orbicularis oculi contracts to close the eye. The muscle of
Riolan (also known as the pars ciliaris) is another section of the palpebral portion of the
orbicularis oculi; it lies near the lid margin to maintain the margins next to the globe. The
orbicularis oculi is the major muscle responsible for closing the eyelids.
✔✔Tear volume in a normal, healthy, young adult measures approximately between
which of the following values?
13.0-16.0 microliters
6.0-8.0 microliters
17.0-20.0 microliters
2.0-5.0 microliters
9.0-12.0 - ✔✔Tear volume has been measured by several methods to be approximately
6-7 microliters in normal individuals, with lesser values occurring in conditions of
aqueous tear deficiency. This has implications for drug delivery, since the normal
ophthalmic drop volume varies between 25 and 50 microliters, effectively overwhelming
the native tear value upon instillation.
✔✔The lymphatic system serves many important roles in the human body. The lateral
portion of the eyelid lymphatics drain into which of the following structures?
The puncta
The conjunctiva
The submandibular lymph node
The pre-auricular lymph node - ✔✔The lateral 2/3 of the upper lid and the lateral 1/3 of
the lower lid lymphatics drain into the pre-auricular lymph node located directly in front
of the ear. The medial 1/3 of the upper eye lid and the medial 2/3 of the lower lid
lymphatics drain into the submandibular node located just under the jaw-line. Therefore,
it is very important to evaluate these two nodes separately, especially when a condition
of viral etiology is suspected.
✔✔A 2.5x Galilean telescope has a -25D ocular lens. When focused for infinity, what is
the length of the telescope?
5 cm
4 cm
6 cm
10 cm
14 cm - ✔✔M = -Doc/Dobj where Doc=power ocular; Dobj= power objective; t=
separation of lenses
2.5= - (-)25/Dobj
Dobj= 10D
t= f'obj + f'oc
f'obj=1/10D = 0.10 m
f'oc = 1/-25D = 0.04 m
t=0.10 + -0.04 = 0.06 m or 6 cm
