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Anatomy and diseases of the orbit
Anatomy of the orbit:
It is pyramidal in shap- the base is
represented by the orbital margin and the apex
by the optic foramen. The walls of the orbit are:
1)Roof
2)Medial wall
3)Lateral wall
4)Floor
It has 3 openings:
1)Optic foramen transmitting optic nerve and
ophthalmic artery.
Anatomy of the orbit
2)superior orbital fissure transmitting
3rd,4th,6th cranial nerves and branches of
ophthalmic division of 5th cranial nerve
,superior ophthalmic vein .
3)inferior orbital fissure – transmitting the
zygomatic nerve, infra orbital nerve etc.
From the surgical point of view there are 4spaces.
1) the subpetiosteal space between the bones of
the orbital wall and the periosteum .
2)The peripheral space between tha periosteum
and the extraocular muscles,which are joined
by fascial connections .
3) Central space or muscle cone – a cone shaped raea
enclosed by muscles .
4)Tenon s space around the globe .
Orbital cellulitis:
Definition : Inflammation of the cellular tissue of the
orbit
Etiology:
1) It is due most frequently to extension of
Inflammation from neighbouring parts , especially the
para nasal sinuses (ethmoid etc .) teeth in children ,
orbital periostitis .
2) Deep injuries especially those with retained foreign
body .
3) septic operation , particularly enucleation of eye
ball
4)Facial erysipelas
5)Metastasis in pyaemia
6) extension of Inflammation in panophthalmitis
,dacryocystitis .
Orbital cellulitis
Symptoms:
1-constitutional symptoms-high fever, vomiting ,
violent pain in the orbit.
2- vision may be effected .in some cases it may be
reduced owing to optic neuritis .
3-diploppia
4-cerebral symptoms such as convulsions may be
added.
Signs:
It is usually unilateral :
1-Lid swollen , oedematous
2-Conjunctiva – ciliary and conjunctival congestion
chemosis of conjunctiva .
3-Proptosis and marked limitation of movement of
eyeball.
4-After sometime pus appears at a certain part of the
skin of lids (usally below supra orbital margin ) and
perforates or less frequently it may empty into the
superior fornix. After evacuation of pus ,pain subsides.
5-Fundus may be normal or may show picture of
papilloedema or optic neuritis- blurred disc margin
,hyperaemia of the disc etc.
Differential diagnosis:
Orbital cellultis
Panophthalmitis
Cavernous sinus
thrombosis
(1) Unilateral
Unilateral
Initially unilateral
but soon becomes
of intercavernous
communications.
(2) Vision not
affected in early
stage.
Complete loss
vision from the
onset.
Vision not affected
in early stage
(3) Cornea, AC are
normal.
Cornea may show
perforated ulcer
whole eyeball full
of pus.
Corneal insensitive.
(4) Pupil normal.
Cannot be seen.
Semidilated and
fixed.
(5) Marked
limitation of
movement of
eyeball.
Partial limitation of Marked limitation
movement of
of movement of
eyeball.
eyeball.
(6) No oedema over No oedema over
mastoid region.
mastoid region.
Oedema over
mastoid region due
thrombosis of
emissary vein.
(7) Consitutional
symptoms _ fever
Mild
Sever, patient may
be in cornea.
(8) Prognosis of
vision and life
good.
Prognosis of vision
poor, life good.
Prognosis of life
serious.
Complications :
1-Thrombosis of central retinal vein.
2-Cavernous sinus thrombosis.
3-Due to exposure of cornea _ ulcer develops ,
perforation of ulcer leads to panophthalmitis .
4-Purulent meningitis, cerebral abscess.
5-Optic atrophy.
Treatment:
1-General treatment by antibiotics – chloromycetin
250 mg q.i.d. injection crystalline penicilline 5 -10
lakhs q.i.d.
2-Analgesics / antipyretic tab. Paracetamol .
3-Hot fomentation.
4-Peripheral surgical space – opened by an incision
through the skin at the orbital margin .This
operation is to be undertaken only when the pus is
pointing under the skin .
5-Cause and source of infection (paranasal sinuses
ets. )should be determined and treated .
Cavernous sinus thrombosis:
Etiology :
This may be due to extension of thrombosis from
various sources. The anatomy of the venous
channels which communicate with the cavernous
sinus is of great importance in this connection.
Infection may occur via :
1-Orbital veins as in erysipelas , furuncle of face
and orbital cellulites .
2-Infective condition of mouth , pharynx , ear ,
nose and accessory sinuses.
3-Metastases as in pyaemia.
Cavernous sinus thrombosis
Symptoms :
1-There is severe supra orbital pain owing to involvement of
the branches of the ophthalmic division of the 5th cranial
nerve.
2-Constitutional symptoms – high grade fever , vomiting .
3-Vision may not be affected in early stage; later it may be
reduced owing to optic neuritis.
4-Cerebral symptoms may be severe and patient may be
comatose.
Signs:
Initially it may be unilateral later it becomes bilateral.
This is because the cavernous sinus of one side
communicates with that of the other by 2 transverse sinuses .
The first sign is often paralysis of the opposite lateral rectus.
1- The lids are oedematous and swollen. In addition there is
oedema over the mastoid region behind the ear due to
thrombosis of emissary vein.
2) Congestion and chemosis of conjunctiva.
3) Proptosis and limitation of movement (due
to involvement of 3rd,4th and 6th cranial nerves)
4) The cornea is insensitive due to involvement
of 5th cranial nerve.
5) The pupil is semidilated and fixed due to the
involvement of 3rd cranial nerve.
6) Fundus examination shows typical picture
of papilloedema or papillitis.
Differential diagnosis : Refer orbital cellulitis.
Treatment :
1) Massive doses of intravenous
antibiotics 25 mega units of penicillin,
methicillin, oxacillin, cloxacillin.
2) Anticoagulants – heparin,
dicoumarol.
Proptosis (exophthalmos)
Proptosis (exophthalmos) :
Abnormal protrusion of the globe is called
proptosis or
exophthalmos. It is due to many causes, among which
increase
in the orbital contents is the most important. Accurate
estimates
of the amount of proptosis can be obtained by special
mechanical
devices known as exophthalmometer e.g. Hertel`s
exophthalmometer.
Causes of unilateral proptosis:
I) Inflammatory causes:
1) Orbital cellulitis
2) Panophthalmitis
3) Dacryoadenitis
4) Pseudo-tumour
II) Cysts and tumours of orbit :
1) Dermoid cyst , parasitic cyst
2) Benign tumour-haemangioma
3) Malignant tumour – rhabdomyosarcoma , lymphosarcoma, adenocarcinoma of lacrimal gland.
4) Tumour of optic nerve-glioma
5) Tumours extending from the eye ball – retinoblastoma,
malignant melanoma of choroid.
6) Tumours extending from the cranium - meningioma
of sphenoid ridge.
7) Tumours extending from paranasal sinuses – like
maxillary antrum, and from nasopharynx.
8) Metastases from carcinoma breast, cervix, thyroid.
III) Traumatic
1) Retrobulbar haemorrhage
IV) Vascular
1) Varicosity of orbital veins – causes
intermittent proptosis.
2) Carotico cavernous fistula
Causes of bilateral proptosis:
1) Endocrine exophthalmos – both thyrotoxic
and thyrotrophic.
2)Cavernous sinus thrombosis.
3) Leukaemia
4) Developmental anomalies of the skull and
orbit as in oxycephaly.
5) Hand – Schuller Christian disease.
Causes of pulsatng proptosis:
1) Carotico – cavervous fistula – there is
communication between the internal carotid artery
and cavernous sinus.
2) Von – Reckling-hausen`s disease or
neurofibromatosis:
due to erosion of the roof of the orbit the cerebral
pulsations are transmitted to the orbit.
ENDOCRINE EXOPHTHALMOS :
Graves` disease :
It is well recognised that
exophthalmos with the associated ocular
manifestations and the general signs of
hyperthyroidism may appear together or
separately or vary independently. They can be
considered as 2 aspects of one disorder – Graves`
disease :
1) Hyperthyroidism or the general thyrotoxic
component.
2) Ophthalmic form which may be
a) Thyrotoxic exophthalmos
b) Thyrotrophic exophthalmos.
Graves` disease
Etiology :
1) Hyperthyroidism is caused by an increase in the
circulating level of thyroid hormone.
a) Auto – immune disease : LATS may be an
antibody to some thyroid antigen and the reaction
with the latter may trigger of the thyroid over activity.
b) Genetic factor
2) Ophthalmic features : The ocular
manifestation do not respond satisfactorily to
antithyroid drugs, radioactive iodine or
thyroidectomy like the general features of
hyperthyroidism.
Cross reaction between thyroid and eye muscle
antigens with subsequent infiltration by
lymphocytes and inflammatory edema is believed
to be responsible for exophthalmos.
Thyrotoxic exophthalmos
thyrotrophic
or progressive exophthalmos or
Malignant exophthalmos
exophthalmos
1) most commonly seen in
hyperthyroid patients
2) lid retraction due to…
a) overaction of L.P.S
(levator palpebrae superioris)
b) overaction of Muller's
muscle.
Rim of sclera seen above
The cornea ,it becomes wider
As the eyes are depressed
(lid lag) Von Graefe's sign.
. ..Most commonly seen in
euthyroid (normal thyroid)
patient.
…. lid retraction seen in
initial stage .later this
is replaced by sewlling
of eye lids and even
Ptosis.
3) no chemosis of conjunctiva
...chemosis of conjunctiva.
4) exophthalmos mild or
moderate symmetrical and
reducible on pressure.
…severe and asymmetrical
irreducible on pressure.
5) ophthalmoplegia slight
Weakness of convergence
(Mobius sign) .
6) Fundus-normal .
….external ophthalmoplegia
may occure.
…May show papilloedema,
Optic atrophy.
Treatment :
• Hyperthyroidism
1. Medical – carbimazole , methyl or propyl
thiouracil
2. Radioactive iodine.
3. Surgical –subtotal thyroidectomy
•
1.
2.
3.
Ocular features
0,7% methyl cellulose drops to protect the cornea
Guanethidine (adrenergic blocking agent) drops
Lateral tarsorrhaphy in case of lagophthalmos to
protect the cornea from exposure keratitis.
4. Radiotherapy to orbit.
5. Systemic cortico steroids in some cases of malignant
exophthalmos.
Enophthalmos
Enophthalmos
Abnormal retraction of the eye ball is called
Enophthalmos . it is rare.
Causes of Enophthalmos:
blow out fracture of orbit
horner's syndrome due to paralysis of cervical
sympathetic.
Duane's retraction syndrome due to muscular facial
anomalies of lateral and medial recti.