to download this presentation from this link https://mohmmed-ink.blogspot.com/2020/11/the-lacrimal-system.html lacrimal system anatomy and clinical

3. the lacrimal glands normally
produce about 1.2 μl of tears per minute. Some
are lost via evaporation.
The remainder are drained via the naso-
lacrimal system.The tear film is reformed
with every blink.

4. Abnormalities are found in:
1. tear composition.
2. the drainage of tears.

5. ABNORMALITIES IN COMPOSITION
If certain components of the tear film are
deficient or
there is a disorder of eyelid apposition
then there can be a disorder of ocular
wetting.

6. A deficiency of lacrimal secretion occurs with
age and results in keratoconjunctivitis sicca
(KCS) or dry eyes..

7. When this deficiency is associated with a
dry mouth and
dryness of other mucous membranes the condition is
called primary Sjögren’s syndrome
When KCS is associated with an auto-immune
connective tissue disorder the condition is called
secondary Sjögren’s syndrome.
is the commonest of these
associated disorders

8. Patients have non-specific symptoms of
grittiness, burning, photophobia,
heaviness of the lids and ocular fatigue. These
symptoms are worse in the
evening because the eyes dry during the day.
In more severe cases visual acuity may be
reduced by corneal damage.

9. In mild cases there are few obvious signs.
Staining of the eye with fluorescein will
show small dots of fluorescence
(punctate staining) over the exposed
corneal and conjunctival surface.
In severe cases tags of abnormal mucus
may attach to the corneal surface
(filamentary keratitis) causing pain due
to tugging on these filaments during
blinking

10. 1- Supplementation of the tears with tear
substitutes helps to reduce symptoms.
2-In severe cases it may be necessary to
occlude the punta with plugs, or more
permanently with surgery, to conserve the
tears.

11. ,
but particularly in cicatricial conjunctival
disorders such as erythema multiforme
(Stevens–Johnson’s syndrome)

12. there is an acute episode of
inflammation causing macular ‘target’ lesions
on the skin and discharging
lesions on the eye, mouth and vulva. In the eye
this causes conjunctival
shrinkage with adhesions forming between the
globe and the conjunctiva (symblepharon).

13. There may be both an aqueous and mucin
deficiency and
problems due to lid deformity and trichiasis.

14. 1-Chemical burns of the eye,
particularly by alkalis
2- trachoma (chronic inflammation of the
conjunctiva
caused by a type of chlamydial infection;

15. The symptoms are similar to those seen with
an aqueous deficiency.
Examination may reveal scarred, abnormal
conjunctiva and areas of fluorescein staining.
Treatment requires the application of artificial
lubricants.

16. is a condition causing childhood
blindness on a worldwide scale. It is associated with
generalized malnutrition
in countries such as India and Pakistan. Goblet cells are lost
from
the conjunctiva and the ocular surface becomes keratinized
(xerosis). An
aqueous deficiency may also occur.
The characteristic corneal melting and perforation which
occurs in this condition (keratomalacia) may be
prevented by early treatment with vitamin A.

17. Abnormal or inadequate production of
meibomian oil
Absence of the oil layer causes tear film
instability, associated with
blepharitis

18. If the lid is not apposed to the eye (ectropion),
or there is insufficient closure of the eyes (e.g.
in a seventh nerve palsy or if the eye
protrudes (proptosis) as in dysthyroid eye
disease) the preocular tear film will not
form adequately

19. Correction of the lid deformity is the best answer to the
problem. If the defect is temporary, artificial tears and
lubricants can be
applied. If lid closure is inadequate a temporary ptosis can be
induced with
a local injection of botulinum toxin into the levator muscle. A
more permanent
result can be obtained by suturing together part of the apposed
margins of the upper and lower lids (e.g. lateral tarsorrhaphy;

21. When tear production exceeds the capacity of the
drainage system,
excess tears overflow onto the cheeks. It may be
caused by:
•00irritation of the ocular surface, e.g. by a corneal
foreign body, infection
or blepharitis;
•00occlusion of any part of the drainage system
(when the tearing is
termed epiphora).

22. Obstruction of tear drainage (infant)
The naso-lacrimal system develops as a solid cord which
subsequently
canalizes and is patent just before term. Congenital obstruction
of the
duct is common. The distal end of the naso-lacrimal duct may
remain
imperforate, causing a watering eye. If the canaliculi also
become partly
obstructed the non-draining pool of tears in the sac may
become infected
and accumulate as a mucocoele or cause dacrocystitis.

23. Diagnostically the
discharge may be expressed from the puncta by pressure over
the
lacrimal sac. The conjunctiva, however, is not inflamed. Most
obstructions
resolve spontaneously in the first year of life. If epiphora
persists beyond
this time, patency can be achieved by passing a probe via the
punctum
through the naso-lacrimal duct to perforate the occluding
membrane
(probing). A general anaesthetic is required.

24. The tear drainage system may become blocked
at any point, although the
most common site is the naso-lacrimal duct.
Causes include infection or
direct trauma to the naso-lacrimal system.

25. The patient complains of a watering eye
sometimes associated with
stickiness. The eye is white. Symptoms may be
worse in the wind or in
cold weather.There may be a history of
previous trauma or infection.

26. SIGNS
A stenosed punctum may be apparent on slit
lamp examination. Epiphora
is unusual if one punctum continues to drain.

27. Acquired obstruction
beyond the punctum is diagnosed by syringing the naso-lacrimal system
with saline using a fine cannula inserted into a canaliculus.
A patent system is indicated when the patient tastes the saline as it reaches
the pharynx. If
there is an obstruction of the naso-lacrimal duct then fluid will regurgitate
from the non-canulated punctum. The exact location of the obstruction
can be confirmed by injecting a radio-opaque dye into the naso-lacrimal
system (dacrocystogram); X-rays are then used to follow the passage of the
dye through the system.

28. It is important to exclude other ocular disease that may
contribute to watering such as blepharitis. Repair of the
occluded naso-lacrimal duct requires surgery to connect the
mucosal surface of the lacrimal sac to the nasal mucosa by
removing the intervening bone (dacryocystorrhinostomy or
The operation can be performed through an incision on the
side of the nose but it may also be performed endoscopically
through the nasal passages thus avoiding a scar on the face.

30. Closed obstruction of the drainage system predisposes to infection
of the sac (dacryocystitis; Fig. 6.4). The organism involved is usually
Staphylococcus. Patients present with a painful swelling on the medial side
of the orbit, which is the enlarged, infected sac.Treatment is with systemic
antibiotics.
A mucocoele results from a collection of mucus in an
obstructed sac, it is not infected. In either case a DCR may be necessary
to prevent recurrence.