1
The Eyelids
The eyelids protect the eye from injury and excessive light. And prevent
excessive dryness of the cornea and conjunctiva.
Macroscopic anatomy:
The eyelids are two movable mucocutaneous folds, which act as shutters.
The upper lid extends above to the eyebrow while the lower lid passes
without a line of demarcation into the skin of the cheek.
The palpebral fissure is the space enclosed between the two lid margins
when the lids are open.
In adults the palpebral fissure is 30 mm in length and 15 mm in width.
Microscopic Anatomy:
The eyelid is formed of 6 layers:
1. Skin: very thin skin loosely attached to the underlying structures.
2. Subcutaneous areolar layer: loose connective tissue containing no fat.
3. Muscular layer: containing the levator palpebrae superioris, and
Muller's muscle.
4. Submuscular layer: loose connective tissue containing the main blood
vessels and nerves of the lid.
5. Tarsus: the tarsal plate is a condensed fibrous tissue resembling
cartilage it acts as the skeleton of the lid.
6. Palpebral conjunctiva: The conjunctive is very thin, vascular, and
firmly adherent to the tarsus by fibrous bands.
The muscles of the lid:
Orbicularis oculi muscle: the orbicularis muscle is the sphincter of the
lid and has 3 portions.
1. Palpebral portion:
it is the central part of the muscle and may be divided into presseptal and
pretarsal parts.
Action: simple closure of the lids as in blinking. It supports the lower
lid in its place.
2. Orbital portion:
Action: tight closure of the lids.
2
3. Horner's muscle (pars lacrimalis):
a thin layer of muscle fibers arising from the posterior lacrimal crest and
lacrimal fascia, when this muscle contracts it opens the lacrimal sac
Nerve supply:
the orbicularis muscle is supplied by the 7th cranial nerve (facial) .
Levator palpebrae superioris muscle:
Origin: the levator muscle arises from the lesser wing of the sphenoid
bone at the apex of the orbit.
Insertion: the muscle has several insertions
1.
Skin of the upper lid at the upper palpebral sulcus.
2.
Upper tarsus.
3.
Upper fornix of conjunctiva.
Nerve supply: 3rd cranial (oculomotor ) nerve via its superior division
Action: elevation of upper lid.
Paralysis of the levator muscle leads to ptosis
CONGENITAL ANOMALIES OF THE LIDS
1.
Epicanthus :
Definition: Semi- lunar fold of skin at the side of the nose.
Etiology:
1. Congenital.
2.Racial(Mongolians)
3.Familial.
Clinical picture:
1.
Usually bilateral.
2.
Semilunar fold of skin is seen covering the caruncle.
3
2.
LID COLOBOMA : notching of the lid margin ( full thickness
developmental defect)
3.
CONGENITAL MALPOSTION:
a) Ptosis
b) Entropion
c) Ectropion.
4.
DISTICHIASIS: extra row of lashes.
5.
ANKYLOBLEPHARON: Adherent lid margins.
BLEPHARITIS
Belpharitis usually presents as a chronic blepharoconjunctivis and it is the
most common external eye disorder in clinical practice.
Types:
1.
Squamous Blepharitis :
Low grade infection on top of abnormal secretions of the lid similar to
seborrheic dermatitis.
Clinical picture:
1.
Small, white, scales are present between the lashes.
2.
Removal of the scales reveals a hyperemic lid margin without
ulceration.
Treatment:
1.
General treatment of seborrhea.
2.
Remove scales with 3% sodium bicarbonate or diluted baby
shampoo.
3.
Rub antibiotic ointment into the lid margin.
4.
The treatment must be prolonged 2 – 3 weeks.
4
2.
Ulcerative Blepharitis:
Etiology:
Infection
of
the
lid
margin
with
staphylococcus
aureus
(sebaceous, sweat gland and hair follicles)
Signs:
a.
Yellow crusts glue the lashes together.
b.
Minute ulcers of the lid margin which bleed easily when crusts are
removed.
Treatment:
Lid hygiene
I.
Frequent massage to evacuate meibomian secretions
II.
Meticulous removal of scales by scrubbing the lid margins with
baby shampoo or 3% sodium bicarbonate lotion.
Elimination of infection
INFLAMMATION OF THE GLANDS OF THE LID
1.
Stye: (Hordeolum externum)
Acute suppurative inflammation of Zeis gland and the lash follicle,
forming a small abscess.
Etiology:
1.
Infection of a Zeis gland by staphylococcus aureus
2.
Predisposing factors: diabetes, poor general resistance, errors of
refraction and ulcerative blepharitis.
Clinical picture:
Symptoms:
1.
Swelling of the lid
2.
Severe pain, first dull then throbbing.
5
Signs:
Diffuse red swelling
a.
Related to a lash
b.
Close to the lid margin.
c.
Points on the skin side.
Treatment:
1.
Hot fomentations.
2.
Local antibiotic drops and ointment.
3.
Systemic antibiotics.
4.
When pointing occurs. The pus must be evacuated by :
a) Epilation of the related lash
b) Horizontal incision
For recurrent cases: correct the underlying cause
2. Hordeolum internum
Acute suppurative inflammation of the meibomian gland caued by
staphylococcus aureus. It may be primary or it may occur on top of a
chronic inflammation of the mebomian gland (chalazion) Hordeolum
internum should be differentiated from hordeolum externum(stye).
Chalazion (cyst)
It is a chronic non – specific inflammatory granuloma of mebomian
gland.
Etiology:
Etiology unknown. It is a granuloma produced by the retained contents of
the gland following obstruction of its duct, or as a result of chronic
irritation by a low virulence organism.
6
Clinical Picture:
Symptoms:
1.
Painless swelling of a long duration felt under the lids.
2.
Pain occurs only when it become infected
Signs:
A slowly growing painless swelling of the tarsus.
If the lid everted, the conjunctiva is seen red over the nodule.
Treatment:
1.
Very small chalazion: Vitamin A, local antibiotic and steroid
preparation.
2.
Marginal chalazion : scraping from lid margin followed by
diathermy
3.
Moderate or large chalazion: vertical incision and scraping through
the conjunctival side.
4.
Multiple chalazia: combined excision of tarsus and conjunctiva
leaving the lower third of the tarsus (to avoid lid notching) with
replacement by a mucous graft from the lip.
5.
Recurrent chalazion of the same gland: excision biopsy to exclude
malignant tumor.
DISORDERS OF EYELASHES
1.
Trichiasis: Trichiasis is a acondition where more than 4 lashes are
rubbing against the cornea or conjunctiva.
2.
Rubbing lashes: Rubing is a term applied to the condition when 4
lashes or less are misdirected or rub against the cornea or conjunctiva.
3.
Madarosis: permanent absence of eye lashes due to destruction of
the lash follicles.
4.
Distichiasis: An extra row of lashes situated in or near to the
openings of the meibomian glands.
5.
poliosis: whitening of the lashes.
7
MALPOSTION OF THE EYELID
ENTROPION
Definition:
Entropion is the rolling inwards of the eyelid. The whole row of the lashes
will be rubbing against the cornea and finally there will be a deformity of
the tarsus.
Types:
1.
Cicatricial (fibrotic) entropion: Fibrosis of the palpebral conjunctiva
due to trachoma, chemical burns, diphtheria and ocular cicatricial
pemphigoid.
2.
Spastic entropion: due to spasm of orbicularis muscle in response to
ocular irritation e.g inflammation, exposed sutures, operations following
enucleation or enophthalmos.
3.
Involutional (senile) entropion : affects only the lower lid due to
overriding of the preseptal portion of orbicularis muscle over the pretarsal
portion.
4.
Congenital entropion: usually affecting the whole lower eyelid.
ECTROPION
Definition:
Ectropion is rolling outwards of the eyelid from the globe. It usually
affects the lower lid as it stands against gravity.
Types:
1.
Involutional (senile) ectropion: due to senile weakness of the
orbicularis muscle and relaxation of the palpebrall ligaments.
2.
Cicatricial (fibrotic) ectropion: due to scarring and contracture of
the skin of the lower lids by burns, trauma or tumor.
3.
Paralytic ectropion: due to paralysis of orbicularis muscle in facial
nerve palsy.
8
4.
Mechanical ectropion: due to increased weight of lower lid by e. g.
multiple chalazia.
5.
Congenital ectropion: rare
PTOSIS
Definition:
Ptosis is the drooping of the upper eyelid that normally covers the upper
1/6 of the cornea.
Etiology (types)
1.
Myogenic ptosis : due to disorders of levator muscle.
a.
Congenital ptosis: due to dystrophy of levator muscle.
b.
Acquired ptosis: myasthenenia gravis: due to a defect at the
myoneural junction.
2.
Neurogenic ptosis: due to a disorder of nerve supply.
a.
Third nerve palsy: paralytic ptosis (diabetes, congenital, or
traumatic)
b.
Horner's syndrome: due to disorder of sympathetic nerve supply
leading to Mullers muscle paralysis. (partial ptosis, miosis, anhydrosis
and enophthalmos)
3.
A poneurotic ptosis: due to disorder of levator aponeurosis .
a.
Involutional (senile) ptosis: degenerative process with age.
b.
Postoperative ptosis: after cataract or retinal detachment surgery.
4.
Mechanical ptosis:
a.
Excess weight due to edema, trauma, tumor.
b.
Conjunctival scarring.
Important clinical points:
1.
Measurement of degree of ptosis:
9
1.
Measure the vertical distance bet. Center of upper lid margin &
lower limbus (VFH)
-
Normally: 9mm
-
Mild : dropping 1-2 mm
-
Moderate : dropping 3 mm
-
Severe: drooping 4mm or more.
2.
Margin – reflex distance (MRD):
Measure the distance between upper lid margin & corneal light reflex.
-
Normally: 4 – 4.5 mm.
2.
Determine the levator function:
-
Correct head position & ask patient to look down to relax frontalis
ms.
-
Fix eye brow against supra- orbital margin using the thumb to
prevent elevation by frontalis ms.
-
Ask patient to look up.
-
Measure elevation of lid margin in mm using ruler:
Grades: normal
15mm
Good
12 – 15 mm
Fair
5 - 11mm
Poor
4 mm
3.
Test of extra- ocular ms movement: to exclude 3
rd
n. palsy.
4.
Evaluation of ptosis:
Degree of ptosis : measure the height of palperal fissure.
Leavator function: after pressing on the brow to avoid function of
occipitofronalis.
Skin crease.
10
Treatment:
Treatment of congenital ptosis
Amount of ptosis: Severe ptosis should be treated early to prevent
amblyopia.
Bilaterality: Unilateral ptosis should be corrected early to avoid
amblyopia.
Age: Time of surgery at 6 years (school age) allows growth of the muscle,
except in extensive and unilateral cases where has to be corrected earlier.
Associated squint: Should be corrected before ptosis to avoid diplopia.
Associated congenital anomalies as epicanthus should be corrected first
Xanthelasma:
Subcutaneous deposits of cholesterol in the medial canthus region. It is
seen in diabetics and in patients with hypercholesterolemia.