Day 2 (1): Physiology of the Eyelids and Methods of Examination Flashcards
Upper and lower eyelid with respect to the limbus
Upper eyelid: covers the superior 1-2 mm of the superior limbus
Lower eyelid: tangential to the inferior limbus
Layers of the eyelids
A. Anterior Lamella
- Skin
- OO
- Preseptal fat pads
B. Orbital Septum
C. Middle Lamella
- Pre-aponeurotic fat pads
- Levator aponeurosis/muscle
- Muller’s muscle/Superior Tarsal Muscle
D. Posterior Lamella
- Tarsus
- Palpebral conjunctiva
Functions of the eyelids
- Integrity of corneal surface and tear film
- Proper position of the globe within orbit
- Protection from external environment
- lashes: sensory
- blinking: reflexive and spontaneous
- glandular secretions - Light regulation (by blinking)
- Cosmesis
Describe the cilia of the eyelids.
- Upper > Lower
- (+) neural plexus
- (+) Glands of Zeis: sebaceous glands at the base of the follicle of each cilia
- lifespan: 3 - 5 mos
- regenerates faster with cutting than epilation
Eyebrows: facial expression, sensor for objects from above
- M: horizontal
- F: arched, lateral 3rd directed to tragus
What are the different glands of the eyelids?
- Main Lacrimal Gland
- exocrine gland in the superotemporal orbit
- secretes aqueous layer of tear film
- REFLEX tear production - Gland of Krause
- accessory lacrimal gland in superior conjunctival fornix
- secretes aqueous layer of tear film
- BASAL tear production - Gland of Wolfring
- accessory lacrimal gland in the non-marginal border of tarsal plate
- secretes aqueous layer of tear film
- BASAL tear production - Gland of Zeis
- SEBACEOUS gland at the base of follicles of the eye lashes - Gland of Moll
- APOCRINE SWEAT glands in eye lid margin - Meibomian Glands
- SEBACEOUS glands at the upper and lower tarsus
- secretes MEIBUM: forms the superficial lipid layer of the tear film
What are the Meibomian Glands
- sebaceous glands imbedded within tarsal plates; upper > lower
- secretes Meibum: superficial lipid layer of the tear film
- prevents evaporation of the mucoaqueous layer beneath
- forms a hydrophobic barrier at the margin of the eyelids preventing spillage of tears
- makes closed lids airtight
What muscles open the eyelids
UPPER Eyelids
- Levator Palpebrae Superioris/Aponeurosis
- innervation: Oculomotor nerve
- yoked to SR: lids will automatically retract with upgaze - Muller’s Muscle/Superior Tarsal Muscle
- innervation: Sympathetic fibers
- smooth muscle attached to the superior aspect of the superior tarsus - Frontalis Muscle
- innervation: Facial nerve
- action: elevates eyebrows
LOWER Eyelids (Retractors)
- Capsulopalpebral Head/Fascia
- originates from the IR - Inferior Tarsal Muscles
- innervation: Sympathetic fibers
What is the Bell’s Phenomenon
Palpebral Oculogyric Reflex
- Reflexive UPward and OUTward movement of the eyes for 15 degrees when eyelids are FORCIBLY CLOSED
- Present in majority of the population
- Defensive mechanism to protect cornea against sudden contact with noxious stimuli
- Reason why traumatic abrasions are commonly found in the INFERIOR or CENTRAL cornea
- NOT found in REFLEX blinking
- Afferent: Facial n. (to orbicularis oculi)
- Efferent: Oculomotor n. (to SR)
- Observed in Bell’s Palsy because of lagophthalmos
What is the Inverse Bell’s Phenomenon?
- Eye moves DOWNward instead of upward with FORCEFUL closure of eyelids
- Result: Exposure Keratitis
Causes:
1. Immediate post-op from eyelid sx causing edema around SR
2. Pts with ptosis
3. Hx of multiple sx for ptosis: inadvertent injury to SR or CN III
What muscle closes the eyelids?
Orbicularis Oculi
- innervation: Facial nerve
- Orbital: anterior to orbital rim
- Preseptal: anterior to orbital septum
- Pretarsal: anterior to tarsal plate
Embryology of lacrimal drainage
- 7 mm embryo: Naso-optic fissure
- Shallows + formation of solid rod of surface epithelium
- 32-36 mm: Canalization of lacrimal sac –> canaliculi –> NLD
- 7 mos AOG: Eyelids separate; puncta open
Lacrimal clearance is facilitated by what processes?
- Evaporation: 25%
- Lacrimal Pump system: 75%
- with some capillary action and effect of gravity - Residual/Krehbiel Flow
- Conjunctival absorption
How does the lacrimal pump system work?
- Lids close: tear film moved medially into the tear lake close to the puncta
- Lids open: tears sucked into and enter the puncta and canaliculi by capillary action
- Lids close:
- OO contraction
- medial displacement of horizontal portion of canaliculi (squeezing action)
- pulling force on the insertion of the Jones muscle on the lateral wall of the lacrimal sac
- expansion of the sac and negative pressure inside (suction effect) - Lids open: tears exit into the NLD by gravity
Sequelae of facial nerve palsy in relation to lacrimal drainage
Lacrimal Pump Failure –> Epiphora
- secondary to weakness of OO
What are the theories explaining the lacrimal pump mechanism?
- Jones: lid closure –> pulls on the lateral wall of the lacrimal sac –> negative pressure inside (SUCTION effect)
- Rosengran-Doane: lid closure –> squeezes the walls of lacrimal sac –> positive pressure inside (SQUEEZING effect)
- Becker Tri-Compartment: lid closure –> negative pressure in superior aspect of lacrimal sac
- Thale: helical pattern of collagen, elastic and reticular fibers of lacrimal sac cause contraction likened to wringing a wet cloth
Explain the Jones Theory of Lacrimal Pump
Eyelid closure: Contraction of the Jones muscle (medial deep head of the preSEPTAL OO) attached to the lateral wall of the lacrimal sac pulls the wall laterally causing expansion of the sac and build-up of negative pressure inside (SUCTION EFFECT)
Explain the Rosengran- Doane Theory of Lacrimal Pump
Eyelid closure: contraction of the OO compresses the lacrimal structures causing lacrimal sac to empty
Eyelid opening: relaxation of the OO causes expansion of lacrimal structures creating negative pressure inside which sucks tears into the sac
What are the parts of the examination of the eyelids?
- Gross Examination
- Eyelid Measurements
- Snap Back/Distraction Test: lid laxity
- Eyelid Malpositions: ptosis, ectropion/entropion
- Eyelid Tumors
Distance between the two medial commissures
Inter-Canthal Distance (ICD)
Distance from medial to lateral commissure of one eye
Horizontal Fissure Distance (HFD)
Distance from Hirschberg/corneal light reflex to SUPERIOR eyelid margin center while in PRIMARY gaze
Margin Reflex Distance 1 (MRD1)
- measures degree of ptosis/retraction
Distance from Hirschberg to INFERIOR eyelid margin center while in PRIMARY gaze
Margin Reflex Distance 2 (MRD2)
- measures degree of reverse ptosis/retraction
Distance between superior eyelid margin and upper eyelid fold/superior eyelid crease.
Margin-to-Fold Distance (MFD)
Reminders when taking measurements of the eyelids:
- Eyes in PRIMARY gaze
- Pt and examiner at the same level
- Use transparent millimeter ruler
Principle when repairing eyelid trauma to recreate normal anatomy.
ICD = HFD
Reflection of light on the pt’s cornea with the pt in primary gaze
Hirschberg Light Reflex
What is the importance of Langer’s Lines
- Incision on the face and periorbital skin should fall along Langer’s Lines for better cosmesis
- FISHMOUTH incisions preferred instead of circular to avoid dog ears.
How is levator function measured in patients with ptosis?
- [DOWNGAZE] Ask pt to look down. Location of superior eyelid margin is marked as 0.
- [NEGATE] Negate the action of the Frontalis by pressing on the eyebrows with the thumb.
- [UPGAZE] Ask the pt to look up and note location of superior eyelid margin.
Lid EXCURSION
- measured distance from downgaze to upgaze
What is the normal MRD1 and how is ptosis classified?
Normal: 4 mm
Mild Ptosis: 2 mm
Moderate Ptosis: 1 mm
Severe Ptosis: 0 - 0.5 mm or negative (light reflex not seen)
What is the normal lid excursion measurement and levator function?
Excellent: > 11 mm
Good: 7 - 11 mm
Fair: 5 - 7 mm
Poor: 0 - 4 mm
How to classify pts presenting with blepharoptosis?
- Classify ptosis:
NORMAL: 4 mm
MILD Ptosis: 2 mm
MODERATE Ptosis: 1 mm
SEVERE Ptosis: 0 - 0.5 mm or negative (light reflex not seen)
- Classify levator function/lid excursion:
EXCELLENT: > 11 mm
GOOD: 7 - 11 mm
FAIR: 5 - 7 mm
POOR: 0 - 4 mm
- Determine probable cause:
- MECHANICAL
- APONEUROTIC
- NEUROGENIC
E.g. Mild ptosis with good levator function probably involutional.
Incomplete closure of the eyelids
Lagophthalmos: OO; CN 7
Drooping of eyelids
Blepharoptosis: LPS/LA; CN 3
Review: What are the different measured parameters of the eyelids?
- Palpebral fissure: MRD1 and MRD2
- Lid crease height: MFD
- Horizontal fissure: HFD
- Levator function: Lid excursion (poor, fair, good, excellent)
- InterCanthal Distance: ICD = HFD
- (+/-) Lagophthalmos: if (+), measure distance of opening
- (+/-) Bell’s Phenomenon: if (+) ptosis, measure PUPIL SIZE because CN 3 might also be affected
- OO function: ask pt to forcefully close eyelids then try prying it open with 2 fingers; note if with good resistance
- Botox treatments: tx still working if eyelids are easily pried open
What to take note in pts presenting with eyelid tumors?
- Color
- Consistency (solid, cystic)
- Movement
- Location
- Signs of inflammation: warmth, redness, pain
- Borders (well-circumscribed, poorly-delineated)
- Orbital signs (infiltration of septum: proptosis, resilience, limitations in EOM movement)
- Integrity of normal structures of eyelids
- Lymphadenopathy
What tests are used to check for lid laxity and malpositions?
- Snap Back Test:
- pinch lower eyelids, slightly tug and release
Result:
- Normal/(-) laxity: immediately snaps back
- Grade 1: 2 - 3 s to return to position
- Grade 2: 4 - 5 s
- Grade 3: > 5 s
- Grade 4/Severe: does not return to position
- Distraction Test:
- pull lower lids downward away from the globe and the distance is measured
Result: Medial Canthal Test
- Normal/(-) laxity: 0 - 1 mm displacement
- Grade 1: 2 mm
- Grade 2: 3 mm
- Grade 3: > 3 mm
- Grade 4/Severe: does not return to baseline
Result: Lateral Canthal Test
- Normal/(-) laxity: 0 - 2 mm displacement
- Grade 1: 2 - 4 mm
- Grade 2: 4 - 6 mm
- Grade 3: > 6 mm
- Grade 4/Severe: does not return to baseline
Ectropion vs Entropion vs Trichiasis vs Distichiasis
ECTROPION: outward turning of lid MARGIN
- Involutional
- usually due to aging
- increased horizontal laxity of the lower eyelid
- disinsertion of the lower eyelid retractors - Cicatricial
- due to scar formation or tissue contraction from chronic inflammation, traumatic or iatrogenic
- shortening of the ANTERIOR lamella - Paralytic
- decreased orbicularis muscle tone supporting the lower eyelid - Mechanical
- when a mass, such as a tumor, displaces the lower eyelid margin
Entropion: inward turning of lid MARGIN
- Involutional
- usually due to aging
- most common type of entropion
- due to mechanical failures of horizontal and vertical lid laxity, lower lid retractor weakness, and orbicularis oculi override - Spastic
- intermittent but may be a precursor to persistent lower eyelid malposition
- due to muscle spasm of the orbicularis muscle induced by local irritation, infection or recent ocular surgery - Cicatricial
- results from chronic inflammation, trauma or iatrogenic injury leading to fibrosis and scarring
- shortening of the POSTERIOR lamella - Congenital
- rotated inward since birth
- due to disinserted lower lid retractors, posterior lamella vertical insufficiency or kinking of the tarsal plate
Trichiasis:
- eyelashes are misdirected posteriorly towards the ocular surface
- problem is the direction of lash growth and not a margin malposition
Distichiasis
- growth of lashes from the meibomian gland orifices
Causes of entropion?
- Overriding of preseptal over the pretarsal OO
- preseptal OO can travel superiorly and override the pretarsal OO causing margin to rotate against the eye - Tarsal plate atrophy
- loss of support to lids causing horizontal eyelid laxity
How to differentiate involutional from cicatricial entropion?
Eyelid Margin repositioning using thumb:
- press on the lower eyelid margin to attempt to turn it to normal position
INVOLUTIONAL
- margin returns to normal for a few seconds
CICATRICIAL
- margin immediately snaps back to abnormal position or return to normal position with test not possible (scar tissue pulls margin inwards)
What are the lid stabilizers?
Keeps the lids in their normal position
Horizontal:
1. Tarsus
2. Medial and Lateral Canthal Tendons
Vertical: Lower Lid Retractors
Congenital anomaly where eyelids are underdeveloped.
Blepharophimosis Syndrome
- Blepharophimosis
- horizontal shortening of the palpebral fissures
- eyes appear more narrow - Ptosis
- upper eyelid droop
- vertical narrowing of the palpebral fissures
- due to maldevelopment of the LPS - Epicanthus inversus
- prominent skin folds extending from the lower to the upper eyelid - Telecanthus
- widened distance between the medial canthi
- eyes appear spaced more widely apart
Condition where normal tissue in and around the eye is undeveloped at birth.
Coloboma
Tx: Tenzel Flap
- mobilize skin from temporal region to reconstruct defect in medial eyelids
Primary differential for masses in the eyelids with loss/destruction of surrounding normal structures
Carcinoma
Dx: Biopsy
Tx: Hughes Procedure/Tarsoconjunctival Flap Advancement
- wide excision with reconstruction of the full eyelid defect
Primary differential for midline facial/orbital masses
Rule out Meningocoeles
Guidelines in doing biopsy of eyelid masses.
- Obtain samples on the BORDER of normal tissue and tumor for comparison.
- Avoid necrotic tissues.
- May take multiple samples.
Widespread, persistent, thick, dry, fish-scale like skin
Ichthyosis
- (+) secondary lagophthalmos
- tx: Oral Retinoids
Common sequelae of eyelid or facial burns.
Cicatricial ectropion
- caused by shortening of the anterior lamella (skin and orbicularis muscle)
- contracted scar tissue pulls eyelid margin outwards
- Tx: Full thickness skin graft: replace shortened anterior lamella
Most important diagnostic examination for patients presenting with eyelid masses.
BIOPSY of mass
When to intervene when presented with capillary hemangioma on the eyelids?
Capillary Hemangioma:
- BENIGN overgrowth of capillaries
- presents during 1st year of life
- consideration: intervene if with risk for AMBLYOPIA if tumor is blocking visual field
Considerations in lacerations of the eyelids.
(-) margin involvement: SIMPLE closure
(+) margin involvement: LAYERED closure
- Tarsal plate: Vicryl sutures
- Meibomian line: Silk sutures
- Gray line: Silk sutures
- Lash line: Silk sutures
Dacryocystitis vs Lacrimal Sac/NLD Mass
Dacryocystitis
- acute onset
- swelling and pain BELOW the horizontal midline
- associated with redness and other signs of inflammation
Mass
- subacute to insidious
- swelling and pain CROSSING the horizontal midline
Medial Canthal Tendon
- prevents infection from encroaching upwards
What structures are affected in tear trough deformities?
Orbitomalar ligament = Infraorbital Hollow
Tx: Hyaluronic Acid fillers
- used to fill the area and obliterate shadows
- lasts for 12-18 mos
What is epiblepharon?
- Pretarsal OO and skin ride above the eyelid margin to form a horizontal fold of tissue that causes the cilia to assume a vertical position which can touch the cornea.
Epiblepharon vs Entropion
Epiblepharon
- overriding preTARSAL OO and skin over eyelid margin
- eyelid margin is NOT rotated inwards
Entropion:
- overriding preSEPTAL OO over pretarsal OO
- eyelid margin is ROTATED inward
Aesthetic treatment for pts with small or absent lid creases?
Blepharoplasty
Alternative treatment for pts with CN 7 palsy presenting with lagophthalmos.
Surgical implantation of gold weight in the upper eyelids
- assists eyelid closure with gravity
Surgical intervention that corrects the characteristic signs of aging that occur in the periorbita (excess eyelid skin, lid laxity, orbital fat malposition) through an approach FROM INSIDE the lid
Transconjunctival Blepharoplasty
How does orbital floor blow-out fractures cause limitation in upgaze and downgaze?
Causes entrapment of IO, IR or both in the roof of the maxillary sinus
Upgaze:
1. SR contracts while IR relaxes and extends but since trapped = limited movement
2. IO (elevator) can’t contract properly
Downgaze:
1. IR contracts while IO (and SR) relaxes and extends but since trapped = limited movement
2. IR (depressor) can’t contract properly
What are xanthelasmas and treatment?
Xanthelasmas
- yellowish plaques most commonly near the upper and inner canthus of the eyelids
- deposition of cholesterol-rich material in which lipids accumulate inside foam cells of the skin
- Tx: Fractional Laser Resurfacing
