Ocular Anatomy (with some accidental Disease mixed in) Flashcards
What is sclerotic scatter used to look for?
Corneal edema
What is the illumination angle for sclerotic scatter?
60 degrees
What is an optic section used for?
Depth assessments - angle, corneal lesions
About how wide should an optic section be?
0.5mm
What is specular reflection used for?
Evaluate corneal endothelium and anterior/posterior lens surfaces
What is indirect illumination used to view?
Non-opaque corneal lesions
When a cobalt filter is used without fluorescein, what is highlighted, and in what color, that is commonly found in keratoconus?
Fleischer rings - corneal iron rings
Appear black
What may happen to IOP in cases of severe chemical burns?
Increase
Why are alkali burns worse than acid burns?
They raise tissue pH, breaking down fatty acids, allowing for faster penetration
Which are more common, alkali burns or acid burns?
Alkali - 2x as common
What is the most common cause of alkali burns?
Calcium hydroxide
In which type of chemical burn is limbal blanching more common?
Alkali
What are the common symptoms of a corneal abrasion?
Pain FBS Photophobia Tearing Blurred vision Mild AC reaction Miotic pupil
A corneal abrasion typically stains with fluorescein, but doesn’t have what?
SEIs
What should always be done before removing a corneal foreign body?
Check VA
What is hyphema?
Blood in the AC
What systemic diseases may cause hyphema?
Sickle-cell retinopathy
Clotting disease
(others)
What typically causes hyphema?
Trauma to the iris and/or ciliary body
What should NOT be performed on a patient with hyphema?
Gonio
Scleral depression - they can cause re-bleeds
How long after an injury that causes hyphema can gonio be performed?
About 1 month
What are some additional signs associated with hyphema?
Iris sphincter tear Iridodialysis Cataract (traumatic) Vossius ring on anterior lens capsule Commotio retinae Angle recession
Why might there be a significant IOP increase in a patient with hyphema?
Blood cells block the TM, blocking outflow
What should you ask about if a patient presents with an idiopathic hyphema?
Use of blood thinners
What tests might you order if a patient presents with idiopathic hyphema?
CBC
Prothrombin time/partial thromboplastin time
Sickle cell screen
Which ethnicities have a higher prevalence of sickle cell?
African American
Mediterranean
Which type of intraocular foreign might cause significant inflammation?
Iron
Steel
Copper
Vegetable matter
What bone breaks in an orbital blow out fracture?
Maxillary bone
A patient presents with a blow out fracture and complains of loss of sensation of the cheek. What is the probable cause?
Damage to the infraorbital nerve
What is commotio retinae of the macula termed?
Berlin’s edema
What is iridodialysis?
Disinssertion of the iris root from the ciliary body
If a patient has an iridodialysis, what should they be monitored for?
Angle recession glaucoma
What is Purtscher’s retinopathy commonly associated with?
Chest compressing trauma
What characterizes Purtscher’s retinopathy?
Diffuse retinal hemorrhages
Exudates
Cotton wool spots
Acute pancreatitis may also cause this type of retinopathy that is commonly associated with chest-compressing trauma.
What is: Purtscher’s retinopathy
What does choroidal rupture usually appear as?
Single or multiple areas of subretinal hemorrhage, usually within the temporal posterior pole, with crescent shaped tears concentric to the optic nerve head
Choroidal rupture occurs in 5-10% of what?
Blunt trauma
What is the name for the most superficial portion of the orbicularis oculi?
Muscle of Riolan
What is the function of the Muscle of Riolan?
Keeps lid margin apposed to the globe during eye movement
Do the meibomian glands arise anterior or posterior to the Muscle of Riolan (gray line)?
Posterior
Which is the thinnest of the corneal layers?
Endothelium
What are the layers of the cornea from anterior to posterior?
Epithelium Bowmans Stroma Descemet's Endothelium
Which layer of the cornea thickens with age?
Descemet’s membrane
What vascular system nourishes the lens during fetal development?
Cloquet’s canal (hyaloid vascular system)
What is a remnant of Cloquet’s canal left on the posterior lens called?
Mittendorf dot
What is a Bermeister Papilla?
Remnant of cloquet’s canal left on the optic disc
What 3 cell types are found within the foveola?
PRs (cones)
Glial cells
Muller cells
What 5 retinal layers are found within the foveola?
RPE PRs ELM ONL Henle's fiber layer ILM
What is the size of the fovea?
1.5mm or 1500 micrometers or 1 DD
What are the approximate thickness of the cornea?
Cornea - 550 microns
What is the thickness of the thinnest part of the choroid, and where is it located?
Ora serrata
.1mm
What is the thickness of the thickest part of the choroid, and where is it located?
Posterior pole
.2mm
How thick is the thickest part of the sclera, and where is it located?
1.0mm
Near the ONH
Where is the thinnest part of the sclera, and what does it measure?
Insertions of the rectus muscles
.3mm
How thick, and where is the thickest part of the retina?
Papillomacular bundle
.23mm
How thick, and where is the thinnest part of the retina?
.1mm
Foveola
What are the 2 functions of the ciliary body?
Accommodation
Aqueous humor formation
What 2 cranial nerves transmit parasympathetic innervation to ocular structures?
CN 3
CN 7
Where do the parasympathetics begin for CN 3?
Edinger Westphal Nucleus
What structures and receptors are innervated by the parasympathetics from CN 3?
Ciliary body - M2 and M3 receptors
Sphincter muscle - M3 receptors
From where does the Edinger Westphal nucleus arise?
Midbrain
Where do the parasympathetics begin for CN 7?
Lacrimal nucleus
From where does the lacrimal nucleus arise?
Pons
What structures and receptors are innervated by the parasympathetics from CN 7?
Lacrimal gland - M2, M3 receptors
What is the course of the parasympathetics that arise from CN 3?
Edinger Westphal nucleus
Ciliary ganglion
Innervates ciliary body and sphincter muscle
What is the course of the parasympathetics that arise from CN 7?
Lacrimal nucleus
Sphenopalatine ganglion
Innervates lacrimal gland
Parasympathetics to the eye innervate what 3 structures?
Lacrimal gland (CN 7) Ciliary muscle (CN 3) Sphincter muscle (CN 3)
What 3 structures make up the uvea?
Iris
Ciliary body
Choroid
What is required for the formation of a CNVM?
A break in Bruch’s membrane
What are 4 conditions that can cause a break in Bruch’s membrane?
Exudative ARMD
Lacquer cracks
Angioid streaks
Histoplasmosis
What are the 2 xanthophyll pigments found in the macula?
Lutein
Zeaxanthin
What is the relationship of lutein and zeaxanthin to ARMD risk?
The act as antioxidants, and so protect against ARMD
How many layers of ganglion cells are contained in the macula?
2 or more layers of ganglion cells
What are the 2 types of sinuses within the cranium?
Air - ex. paranasal
Blood - ex. cavernous
What would be the expected facial finding in a patient with a lesion of the superior division of CN III?
Ptosis
What condition results from a lesion at the location of the ciliary ganglion?
Adie’s tonic pupil - the ciliary ganglion carries parasympathetics from CN 3 to the ciliary body and sphincter muscle
What are the findings of Adie’s tonic pupil?
Unilateral dilated pupil
Which nervous system is affected in Adie’s tonic pupil?
Parasympathetic - sympathetic takes over and dilates the pupil
What drug is used for diagnosis of Adie’s tonic pupil?
Pilocarpine 0.125%
Patient’s with Adie’s tonic pupil will have a delayed what?
Light response
Near response
Why do patient’s with Adie’s tonic pupil have a delayed light and near response?
There is a lesion of the ciliary ganglion, which is responsible for both the light and near response
Which cranial nerve is used for shoulder shrugging/head turning?
XI - accessory
The optic nerve gives off fibers to what 3 structures?
LGN
Pretectal nucleus
Superior colliculus
Where do preganglionic parasympathetic fibers that course to the pupil originate?
Edinger Westphal nucleus
Where do postganglionic parasympathetic fibers that course to the pupil originate?
Ciliary ganglion
What bones make up the medial wall of the orbit?
Sphenoid (body)
Maxilla
Ethmoid
Lacrimal
What bone makes up the majority of the floor of the orbit?
Maxillary bone
What degree of abduction makes the inferior rectus the primary depressor?
23 degrees
Which muscle cause intorsion, abduction, and depression?
Superior oblique
When are the oblique muscles responsible for elevation and depression?
When the eye is adducted 51-55 degrees
If a patient is instructed to look straight up, which muscles are performing this action?
Superior rectus
Inferior oblique
Where does the inferior oblique muscle start its course?
Maxillary bone
Which 2 bones make up the lateral wall of the orbit?
Zygomatic bone
Greater wing of sphenoid
(Lateral wall = Great-Z)
The bulbar conj and ciliary body both receive part of their blood supply from which vessels?
Anterior ciliary artery
What comprises the major arterial circle of the iris?
Long posterior ciliary arteries
Anterior ciliary arteries
Where is the major arterial circle of the iris located?
In the ciliary body
Why does a uveitis patient have inflammation of the ciliary body and circumlimbal injection?
Because they are both supplied by the anterior ciliary arteries
Lateral conj lymphatics drain into what?
Preauricular lymph nodes
Medial lymphatics drain into what?
Submandibular lymph nodes
Which glands lubricate the eyelashes?
Glands of Zeis
What is a second major function of the glands of Zeis?
Assist the glands of Moll and meibomian glands to produce the lipid layer of the tear film
Which layer of the tear film is secreted by blinking?
Lipid layer
What produces the lipid layer of the tear film?
Goblet cells
A deficiency in what will cause decreased production from goblet cells, causing evaporative dry eye?
Vitamin A
Which layer of the eyelid contains goblet cells?
Palpebral conjunctiva
What pupil abnormality would be most prevalent in the light?
Adie’s tonic pupil - (acute, dilated pupil)
Which pupil abnormality is most prevalent in the dark?
Horner’s
Sympathetic innervation to the dilator follows the course of which sensory nerve?
Nasociliary nerve
Sympathetics on the nasociliary nerve have what two options?
Go to pupil dilator
Go to Muller’s muscle
What nervous fibers does a pancoast tumor upset?
Sympathetic fibers
What are the symptoms of a pancoast tumor?
Miosis Ptosis Reverse ptosis Anhydrosis Dilation lag (Much like Horner's)
Does a Pancoast tumor affect pre or post ganglionic sympathetic fibers?
Preganglionic - synapse in the superior cervical ganglion
Why does Bell’s cause ipsilateral paralysis?
It is damage to a lower motor neuron, so it stays ipsilateral
What is the main ocular concern with Bell’s palsy?
Exposure keratopathy
Bell’s palsy is an idiopathic palsy of what nerve?
CN 7
What is the main ocular function of CN 7?
Close the eye
A patient with a pupil involved CN 3 palsy should be suspected of an aneurysm at the junction of what 2 arteries?
Posterior communicating artery
Internal carotid
A pupil sparing CN 3 palsy typically occurs from what 2 systemic diseases?
HTN
DM
A lesion of the facial nerve would elicit what symptoms?
Loss of anterior 2/3 taste
Loss of facial expression
Loss of lacrimation
Loss of sound dampening
Which cranial nerve is most likely affected in a patient with papilledema?
CN VI - due to the intracranial course ( and no protection by the cavernous sinus, like the other nerves) a rise in pressure will most affect this nerve
What nerve innervates the lateral conj and lateral portion of the upper eyelid?
Lacrimal nerve (of V1)
What nerve innervates the lateral part of the lower eyelid?
Zygomatic nerve (of V2)
A palsy of which muscle will cause a patient to tilt their head to to opposite side of the palsy?
CN 4 - the entire nerve decussates, and the head tilts toward the side of the nuclear lesion, but away from the palsy
Which extra ocular muscle has a different anatomical and physiological origin?
Superior Oblique
What is the anatomical origin of the superior oblique?
Lesser wing of the sphenoid, and common tendinous ring (annulus of Zinn)
What is the physiological origin of the superior oblique?
Trochlea
Inability for a patient to look up during abduction is most likely a result of a lesion of what nucleus?
Contralateral superior rectus
-SR fibers decussate
Which lens fibers are the most immature?
Lens cortex
Which region of the lens continues to grow throughout life?
Cortex
What are the vitreo-retinal attachments from strongest to weakest?
Ora serrata Posterior lens Optic nerve Macula Retinal vessels
The posterior pigmented iris epithelium is continuous with what?
Nonpigmented ciliary body epithelium and neural retina
How does accommodation influence IOP?
Ciliary muscle contracts, pulling on the scleral spur, which is attached to the TM, pulling it open and opening the pores, increasing outflow
Where do the lens zonules begin?
Pars plana of the ciliary body
What part of the ciliary body secretes aqueous?
Pars plicata
What is another name for the pars plicata?
Corona cilaris
What percent of the eye does the vitreous comprise?
80%
The pupillary ruff is formed by what layer of the iris?
Posterior pigmented epithelium
Which layer of the iris is the primary contributor to iris color?
Anterior border layer
Which iris layer is a minor contributor to iris color?
Iris stroma
Which veins drain Schlemm’s Canal?
External collector channels
Deep scleral venous plexus
Intrascleral veins
Episcleral veins
Where do corneal stem cells originate?
At the Pallisades of Vogt (limbus)
Which corneal epithelia cells are the only type that undergo mitosis?
Basal cells
Corneal limbal stem cells become what type of cell?
Basal cells
When a corneal basal cells undergoes mitosis, what does it produce?
Wing cells
What is the approximate axial length of the adult eye?
24mm
Which is the most anterior angle structure?
Schwalbe’s line
Which is the most posterior angle structure?
Iris
Which layer of the eye is considered avascular?
Sclera
Which areas of the eye have non-fenestrated capillaries?
Iris
Retina
Which areas of the eye have fenestrated capillaries?
Ciliary body
Choroid
What can pass through the tight junctions of non-fenestrated capillaries?
Water
Small ions
What nerves supply the cornea?
Long ciliary nerves
Short ciliary nerves
-both are branches of V1
Where do corneal nerves enter the cornea?
Mid-stromal region
Which layer of the cornea is devoid of nerve supply?
Descemet’s membrane
Why type of nerve endings are found in the cornea?
Open ended
AKA nocioreceptors
What is the approximate volume of the orbit?
30 cc
-Globe is 6.5cc
About what percent of the orbit is occupied by the globe?
22%
What is the purpose of the Valve of Hasner?
To prevent nasal cavity fluid from entering the nasolacrimal system
Where is the lacrimal gland located?
In a fossa of the frontal bone
What types of tears does the lacrimal gland shed?
Reflex tearing
Emotional tearing
What glands shed maintenance tears?
Accessory lacrimal glands
A 45 y/o man has a loss of corneal sensation, cannot abduct, and tilts his head to his left shoulder as you examine him. No facial asymmetry is found, nor are there hearing difficulties. Where is the site of the lesion?
Cavernous sinus
-Symptoms stem from affected CNs IV, V1 and VI
Macular sparing homonymous hemianopsias are often the result of what?
Stroke
What two arteries supply the macula?
Middle cerebral artery
Posterior cerebral artery
A cuneus gyrus lesion would give what VF defect in the macula?
Inferior VF defect
-That is where superior fibers terminate
A temporal lobe lesion would yield what VF defect?
“Pie in the sky”
A parietal lobe lesion would yield what VF defect?
“Pie on the floor”
-You “Par(ietal)ty on the floor)
Which fibers would medial in the left optic tract?
Ipsilateral superior temporal
Contralateral superior nasal
Superior fibers in the optic tract always go which way?
Medial
Inferior fibers in the optic tract always go which way?
Lateral
Which optic nerve fibers never cross?
Temporal fibers
The left optic tract carries what fibers?
Ipsilateral temporal fibers
Contralateral nasal fibers
Contralateral nasal macular fibers
Which region of the optic nerve head do the superior temporal retinal fibers occupy?
Superior pole
Vision loss from anterior AION results from lack of blood flow through which arteries?
Short posterior ciliary arteries (SPCA)
Where is the thickest region of rods in the retina?
Just outside the perifovea - 5mm outside the foveola
Which region of the macula has the thickest region of ganglion/bipolar cells?
Parafovea
What do neuroglial cells do?
Glycogen metabolism - providing nutrients to the retina
Immunological activities - some are phagocytic
Provide structure, support, and protection
The central retinal artery forms 2 capillary networks within the inner retina. Where are they located?
In the inner nuclear layer (INL)
Where does the first synapse occur in the visual pathway?
Outer plexiform layer
What is the only layer in the retina that receives blood from the central retinal artery and the choriocapillaris?
Outer plexiform layer
Where are the cell bodies for rods/cones located?
Outer nuclear layer
In what layer of the retina are amacrine, bipolar and horizontal cells found?
Inner nuclear layer (INL)
What are the layers of the retina?
-RPE, 2 outer, 2 inner, GNI RPE PRs External limiting ONL - cell body of PRs OPL INL - cell body of bipolar cells IPL GCL - cell body of ganglion cells NFL Inner limiting membrane
The RPE has a tight association with what?
Choroid
RPE is derived from what?
The outer layer of the optic cup
What fibers do the fetal nucleus originate from?
Secondary fibers
Which layer of the lens contains the most crystallins?
Embryonic nucleus
Which layer of the lens has the highest index of refraction?
Embryonic nucleus - because of all the crystallins
Which layer of the lens contains the Y sutures?
Fetal nucleus
What is Henle’s fiber layer?
The outer plexiform layer (OPL) in the foveola
Where does CSF flow within the optic nerve?
Between the pia and arachnoid mater
What is the most common cause of unilateral proptosis?
Hyperthyroidism - it is the number one cause of both unilateral and bilateral proptosis
What is a distinctive sign of a carotid cavernous fistula?
Pulsatile proptosis
Which nerve is responsible for swallowing, and posterior 1/3 taste?
Glossopharyngeal
CN 9 - glossopharyngeal innervates which salivary gland (among other things)?
Parotid - allows salivation
A 40 y/o male reports sudden onset metamorphopsia OD. He had a similar episode about 5 years earlier that “drove him crazy” because it lasted about 3 months. What is the most likely diagnosis?
Central Serous Retinopathy (CSR)
What is the most distinctive FA pattern in CSR?
Smokestack appearance
What are the common signs/symptoms of Phthiriasis palpebarum?
Severe Itching
Pinpoint blood-tinged debris along eyelash margins
Inflamed eyelash margins (but no meibomitis)
What is Phiriasis palpebarum?
Lice
What is madarosis?
Loss of eyelashes
What is the most common etiology for orbital cellulitis?
Extension of a current paranasal sinus infection
What is the main cause of a conjunctival melanoma?
Primary acquired melanosis
What is the most common etiology of conjunctival squamous cell carcinoma?
Conjunctival intraepithelial neoplasia (CIN)
What is the typical demographic for squamous cell carcinoma?
Elderly
Caucasian
Males
What stain is helpful in the diagnosis of squamous cell carcinoma?
Rose bengal
Where does a conj squamous cell carcinoma most commonly arise?
At the limbus - with a feeder vessel
A carcinoma is a cancer of what?
Epithelial tissue
A sarcoma is a cancer of what?
Connective tissue
Which corneal dystrophy is not autosomal dominant?
Macular distrophy (AR)
What is the typical demographic of Fuch’s endothelial dystrophy?
Signs at age 30-40
Symptoms at age 40-50
Female
Often inherited (AD)
What are the common early symptoms of Fuch’s?
Glare
Light sensitivity
What are the common later symptoms of Fuch’s?
Pain (because of bullae) Decreased VA (corneal edema)
What are some early signs/symptoms of Terrien’s marginal dystrophy?
Blurred vision (high astigmatism) Haze in corneal periphery (slowly progresses to circumlimbal peripheral corneal thinning)
What is scleromalacia perforans?
Necrotizing scleritis without inflammation
Scleromalacia perforans is associated with what systemic disease?
Rheumatoid arthritis
What is the worst form of scleritis?
Necrotizing with inflammation
Choroidal melanomas typically arise from what?
Choroidal nevus
What is the most common primary intraocular tumor in adults?
Choroidal melanoma
What are the most common secondary causes of ocular cancer in males and females?
Males - Lung cancer
Females - breast cancer
Choroidal melanomas are more common in which demographic?
Caucasians
What are 3 risk factors for increased progression from dry to wet AMD?
Focal hyperpigmentation
Smoking
Soft drusen
What is the most likely location for a retinal tear?
Superior temporal
What are 2 common causes of exposure keratopathy?
Thyroid eye disease
Ectropion
Name 3 conditions that can cause a mucous tear film deficiency.
Ocular pemphigoid
Steven Johnson’s syndrome
Vitamin A deficiency
What is a common ocular complication of Ehler’s Danlos syndrome?
Lens subluxation
Ehler’s Danlos syndrome is a disorder of what?
Connective tissue
Why is vitamin A deficiency one of the leading causes of blindness in 3rd world countries?
Causes keratinization of the cornea and conj
What is the most common cause of dacryocystitis?
Blockage of the nasolacrimal duct
What things are associated with microcornea?
HVID less than 10mm
Hyperopia
Glaucoma
AD or AR inheritance
What things are associated with megalocornea?
HVID over 13mm
X-linked inheritance
Associated with myopia
What is the buzz-word for Salzmann’s nodular degeneration?
Blue-gray stromal opacities
Unilateral
What are the 4 common etiologies for Salzmann’s?
Dry eye
Trachoma
Phlyctenulosis
Interstitial keratitis
A patient who has suffered what is at higher risk for RCE?
Corneal abrasion
What are the two main etiologies that increase the risk of RCE?
Corneal abrasion Corneal dystrophies (Mainly EBMD)
Retinoschisis is most common in what two retinal locations?
Inferior-temporal
Superior-temporal
What is the inheritance characteristic of juvenile retinoschisis?
X-linked
What is the age classification of a premature baby?
Less than 36 weeks
What is the most common, benign orbital tumor in adults?
Cavernous hemangioma
Where do cavernous hemangioma usually arise?
Directly behind the eye, in the circle of Zinn
What is a common sequelae of a cavernous hemangioma?
Progressive, unilateral proptosis
What is the most common, benign orbital tumor in kids?
Capillary hemangioma
What are the 2 common culprits of Ocular Ischemic Syndrome (OIS)?
Atherosclerosis - most common
Giant cell arteritis
What is the typical presentation of OIS?
Periorbital pain
Gradual VA loss
Unilateral
Midperipheral hemes
What is the most likely etiology of a cavernous sinus thrombosis?
Nasal infection
-Or any infection around the nose or eye
What bacteria is the most common culprit causing a cavernous sinus thrombosis?
Staph aureus
Which causes a higher risk of neovascular glaucoma: CRVO or BRVO?
CRVO
What are the two main risk factors in retinal vein occlusions?
HTN
DM
What is the most common cause of retinal vascular occlusive disease?
Branched retinal vein occlusion
Which corneal layer has the most mitochondria?
Endothelium
- NaK pump uses a lot of energy
What are the average horizontal and vertical dimensions of the ONH?
H: 1.5mm
V: 1.75
What two arteries supply blood to the ONH?
Short posterior ciliary arteries
Central retinal artery - minor contributor
Which portion of the optic nerve has some attachments with EOMs, and causes pain during eye movements in optic neuritis?
Intraorbital
What are the 4 portions of the optic nerve, and their approximate lengths?
Intraocular - 1mm
Intraorbital - 30mm
Intracanalicular - 6-10mm
Intracranial - 10-16mm
What does the optic nerve consist of?
Axons of ganglion cells
How many axons of ganglion cells are found in a typical optic nerve?
1.0 - 1.2 million
The infraorbital nerve is a branch of what nerve?
V2
What bone does the optic foramen pass through?
Lesser wing of the sphenoid
What is another name for the ethmoid bone in the medial wall?
Lamina papyracea
Which orbital wall does not utilize the sphenoid bone?
Floor
What are the 7 bones of the orbit?
Frontal Sphenoid Ethmoid Lacrimal Maxilla Palatine Zygomatic
How many cells thick is the corneal endothelium?
1 cell
What is the main function of the corneal endothelium?
Use NaK pump to remove fluid from the cornea, back into the aqueous
What is the correct order of these muscles from superior to inferior: Superior oblique, Superior levator palpebrae, Superior rectus.
Superior levator palpebrae
Superior rectus
Superior oblique
When does the eye reach maximum size?
Puberty
What is the function of the vortex veins?
Drain the choroid, ciliary body, and iris (vascular tunic)
How many vortex veins are there per eye?
4-7
Muller’s muscle is innervated by what nervous system?
Sympathetic
