Transcript LAC.SYSTEM I-ANATOMY, PHYSIOLOGY, CONGENITAL

O , my sustainer!
Open my Heart
and
make my task easy for me
and loosen the knot from my tongue
so that, they might understand my
speech
Surah Taha (16:25-290)____Al Quran
DR. FAIZUR RAHMAN
Professor of Ophthalmology
PESHAWAR MEDICAL COLLEGE
LEARNING OBJECTIVES
BY THE END OF THE SESSION THE STUDENTS
WOULD BE ABLE TO:
 Correlate the structure of the lacrimal system with its
function and clinical presentation in common clinical
disorders.
 Outline the clinical examination protocol for the assessment
of lacrimal system in patient presenting with epiphora.
Lacrimal System
 Consist of two parts:
Tear production
Tear drainage
 Tear production:
*Main Lacrimal gland
*Accessory lacrimal glands
Glands of Krause
Glands of Wolfring
LACRIMAL GLANDS
 Serous glands
 Situated at the upper and outer angle of the orbit, just
within the orbital margin, in a depression on the
orbital plate of the frontal bone (Fossa for the lacrimal
gland)
Embryology
Lacrimal gland forms as a series of ectodermal buds
that grow supero-laterally from the sup. fornix of the
conjunctiva into the underlying mesenchyme. These
buds then canalize forming the secretary units and
multiple ducts of the gland.
Lacrimal sac and NLD develop as a solid cord of
ectodermal cells between lat. nasal process &
maxillary process of the developing face.
LACRIMAL GLANDS-Anatomy.
 Anteriorly divided by aponeurosis of levator palpabrae
superioris into:
Upper orbital part
Lower palpabral part
 Ducts are 12 in number, pass through the palpabral
part of the gland and open into the conjunctival sac,
4.5 mm above the upper border of the superior tarsus
Location
 LACRIMAL GLAND

LOCATION
LACRIMAL GLAND
LACRIMAL GLAND
12 ducts of the lacrimal gland pass from the
orbital part through the palpebral part into the
superior conjunctival fornix.
In addition to Lacrimal gland, small accessory
glands are also present in the conjunctiva.
In case of non functioning of lacrimal gland, these
glands keep cornea wet .
MICROSCOPIC STRUCTURE
Lacrimal gland is lobulated tubuloacinar structure. On cross section, the
acini are seen as round or tube shaped
masses of columnar cells.
Acini cells 80% are surrounded by
Myoepithelial cells for squeezing out the
secreted fluid.
RELATIONS
Palpebral part of Lacrimal gland lies below the
Aponeurosis of Levator palpebrae superioris.
It extends into the upper eye lid.
Superiorly=Aponeurosis of Levator Palpabrae
Superioris.
Inferiorly= Superior fornix- conjunctiva.
BLOOD SUPPLY
Is from Lacrimal artery ( a branch of Ophthalmic artery) ,
and from Infra orbital artery ( a branch of Maxillary
artery)
VENOUS DRAINAGE
Venous drainage is through Sup. Ophthalmic vein into
cavernous sinus.
LYMPHATIC DRAINAGE
Lymphatic drainage occurs into the superficial Parotid
lymph nodes.
NERVE SUPPLY
Two types of nerve supply that is
Autonomic and sensory nerve supply.
Autonomic nerve supply consist of
Parasympathetic and sympathetic
components.
In parasympathatic system, the Nervous intermedius from
the secretomotor nucleus of Facial nerve join a branch
of Great petrosal nerve to form nerve of Pterygoid
canal which goes to Pterygo palatine ganglion. From
here nerve fibers pass through Maxillary , Zygomatic
N; Zygomatico temporal and finally Lacrimal nerve.
 In sympathatic system, superior cervical
sympathatic ganglion,Plexus of nerves around
ICA, deep petrosal nerve, nerve of Pterygoid
canal, Maxillary nerve, Zygomatic N .Zygomatico
temporal nerve & Lacrimal nerve
Sensory nerve supply;
Lacrimal nerve.
SECRETORY INNERVATION
 LACRIMAL GLAND
 SECRETORY INNERVATION
 POSTGANGLIONIC SYMPATHATIC
FIBRERS
Accessory lacrimal glands
 Same structure as main lacrimal gland
 Very small in size
 Glands of Krause:
20 in number, in the upper lid and 8 in the lower
lid, deeply situated in the conjunctiva near the
fornix on lateral side
 Glands of Wolfring:
are few in number, situated near the upper border
of the tarsal plate
Physiology
 Secretes tear, a slightly alkaline serous fluid.
 Consist of water and minute quantities of sodium
chloride, sugar , urea and protein.
 Contains lysozyme which is bactericidal
 Starts 3-4 weeks after birth.
Tear drainage system
 Consist of puncta, ampula, canaculi, lacrimal sac
and nasolacrimal duct
*Punctum:
Situated near the medial end of each eyelid.
Face slightly posterior in normal condition.
slightly evert the medial end of the eyelid and the
punctum will become visible.
*Ampula: (Vertical canaliculus)
The most proximal portion of the canaculus,
measuring 2 mm.
Tear drainage…cont.
*Horizontal canaliculus:
-8 mm long, in 90% the upper and lower unite to open
in the lateral wall of the sac.
-In 10% both open separately.
-A flap of mucosa (valve of Rozenmuller) prevents
regurg from the sac.
Tear drainage…cont.
*Lacrimal sac:
- It is 10 mm long and lies in the lacrimal fossa.
- Lacrimal bone and frontal process of Maxilla
separate it from middle meatus of nose.
*Nasolacrimal duct:
-Passes down medially & posteriorly to open in the
inferior meatus.
-Opening is gauded by a valve. (valve of Hasner)
Physiology
 Tear drainage:
Tears are drained from conjunctival sac by two
mechanisms:
1. Gravity.
2. Active pump mechanism.
 By gravity:
Gravity plays a small part and most of the tears are
drained by active pump.
Physiology
 Active pump (Suction):
-70% of the tears are drained through the lower
punctum and 30% through the upper punctum
-Upper and lower marginal strips of tears go
medially
-The tears enter the puncta by capillary action and
suction.
- Pretarsal orbicularis oculi splits into superficial
and deep heads around the ampulae and some
fibres are attached to the sac.
Physiology
-During closure of the eye:
*Ampulae is compressed.
*Horizontal canaliculus shortens.
*Puncta move medially.
*Deep head of the orbicularis (attached to sac)
causes dilatation of the sac.
Physiology
All these causes a negative pressure in the sac and tears
are sucked into the sac.
-When the eye closes, the sac goes to its original
volume, forcing the tears into the nasolacrimal duct,
and the puncta move laterally sucking tear into it.
Congenital disorders.
 Canalicular abnormalities:
Very rare and often undiagnosed.
 Absence of punctum:
very rarely one or both the puncta may be absent
congenitally, usually the site may be visible
(congenital stenosis)
Congenital disorders.
 Congenital NLD blockage:
More common condition leading to epiphora in
small children (non-canalization of the NLD cord)
Managed by massages and simple antibiotics till
the age of 6 months in the hope of spontaneous
canalisation
If no improvement in 6 months the probing is tried
three times till the age of 2 years.
Congenital disorders
After the age of 2 years the success of probing decreases
and the child may require a DCR when he/she reaches
the age of 6 years.
EVALUATION
 History
*watering, discharge, swelling and pain
*usually prolonged, usually unilateral
 Examination
*Inspection
ectropion, swelling, fistula
*Palpation
cystic swelling, any stones, regurg test
EVALUATION…Cont.
*Slitlamp exam
*Punctal exam for malposition, stenosis
*Press canaliculus for infection
*Examine marginal tear strip
*Froceful closure of lids—puncta may
evert—lids may overlap
*Fouroscein disappearance test—2
minutes
EVALUATION…Cont.
 Clinical tests
Probing
*Hard stop
*Soft stop
Irrigation
*Canacular block
*Partial block
*NLD block
Patency of Canaliculus
Jones tests
 Jones I (Primary)
Hypersecretion or
Obstruction
 Jones II (Secondary)
Upper passages
obstruction or
Pump failure
Dacrocystography
Types:
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Plain DCG
Distention DCG
Macro DCG
Cinematography
Dacroscintigraphy
Contrast DCG
Digital substraction DCG
Dacrocystography
 Radiopaque dyes:
Lipoidal in water or lipoidal with olive oil
Iodized oil
Neohydroil angioraphin
Dionosil aqueous
Conray
Diagonal viscous
Dacrocystography
 Conventional (Lipiodal ultra fluid is used)
Dacrocystography
Macrodacrocystography
 Computerized:
Subtsaction
Dacrocystography
Dacrocystography
Scintiligraphy
 Dynamic
 Radioactive technetium is used
 Site of obstruction can be documented
Daffodil (Nargus)
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