2.3 Ocular adnexa 1
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What are the ocular adnexa? (6)
- muscles of the eyelids and adjacent facial muscles
- lacrimal apparatus
- orbit and contents - EOM, orbital fat, nerves, vessels
- innervation and vascular supply
Orbicularis oculi is divided into 3 parts. What are they?
- orbital part
- palpebral part
- ciliary part
What is the role of the orbital part of the OO?
What is the role of the palpebral part of the OO?
soft closure e.g. sleeping, blinking
What muscle and nerve is involved in lid closure?
What muscles and nerves are involved in lid opening?
- levator - CN3
- Muller's muscle - sympathetic innervaion
What are the branches of the LPS and what do they give rise to?
- levator palpebrae superioris
- superior - anterior and posterior layers of aponeurosis
- inferior - muller's muscle
The bulbar conjunctiva merges with the __________ at the ___________
The palpebral/tarsal conjunctiva adheres tightly to the ________ and ________ to the inferior lid
- tarsus of the superior lid
- less tightly
Normally there are more lashes in the:
a. upper lid
b. lower lid
a. upper lid
What are the fornices and what do they contain?
- loosely attached conj
- accessory lacrimal glands of Kraus (and Wolfring)
- high conc of goblet cwwla, lymphocytes (CALT)
Where are eyelashes located?
At the anterior tarsal surface between orbicularis oculi and muscle of Riolan
Where do the lashes exit?
At the anterior lid margin and curves away from the globe
What eyelid glands are there?
Meibomian, Zeis, Moll, Krause, Wolfring
What are meibomian glands?
Modified sebaceous glands
What are Zeis glands?
Modified sebaceous glands at base of eyelash follicle
What are Moll glands?
Modified sweat glands
What are Krause and Wolfring glands?
Accessory lacrimal glands
What is trichiasis?
Abnormal misdirected growth of lashes
What is the cause of trichiasis?
Trichiasis is commonly acquired
Trichiasis is often secondary to? (4)
- chronic bleph
- tarsal plate or conj scarring (e.g. trachoma, Stevens-Johnson syndrome
- ageing changes (entropion)
How is pain from trichiasis relieved?
Pull the lid away from the eye
Signs and symptoms of trichiasis (8)
- check history
- posterior misdirection of normal lashes
- most frequently lower lid
- corneal epithelial defects
- red eye
- FB sensation
Complications associated with trichiasis? (3)
- corneal irritation
- worse with blinking
Worst case scenario associated with trichiasis? (3)
- pannus (if long term)
Management of trichiasis? (3)
- treat underlying cause
- treat infection
- remove aberrant eyelashes
How can aberrant eyelashes be removed? (5)
What is trachoma?
A bacterial infection
Epidemiology of trachoma (5)
- ~84mil ppl in 51 endemic countries have active trachoma
- WHO estimates ~6mil cases of blindness due to trachoma occur yearly
- 3% of global blindness
- 7 previously endemic countries (Gambia, Ghana, Iran, Morocco, Myanmar, Oman and Vietnam)
- elimination of blinding trachoma as a public health problem
Cause of trachoma (2)
- Infectious agent: Chlamydia trachomatis
- a gram negative bacteria
Serotypes of C. Trachomatis
- Serotypes A, B, Ba, C: classic trachoma (poor hygeine)
- Serotypes D to K: adult inclusion conjunctivitis (sexually transmitted), neonatal conjunctivitis (Chlamydia most common infectious cause)
- Serotypes L1 to L3: lymphogranuloma venerem (a STD)
What are the two phases of trachoma
Signs during active phase of trachoma (5)
- usually seen in children
- conj inflammation (follicles and papillae)
- limbal follicles
- irritating and watery discharge
Signs during cicatrical phase of trachoma (4)
- tarsal conj scarring(esp upper) - linear/stellate then confluent
- distortion of eyelid and trichiasis
- secondary trichiasis/entropion and associated corneal scarring leading to blindness
- resolved limbal follicles result in gaps in corneal pannus (Herbit's Pits)
Trachoma Grading Scale
- TF: Trachamatous inflammation - follicular
- TI: Trachomatous inflammation - intense
- TS: Trachomatous scarring
- TT: Trachomatous trachiasis
- CO: Corneal opacity
What is distichiasis? (3)
- extra row of lashes arising from meibomian gland orifices
- associated with trichiasis
Causes of congenital distihiasis
- differentiation of complete pilosebaceous glands (hair follicles) cf normal sebaceous (meibomian glands)
- meibomian glands may be abnormal
Cause of acquired distichiasis (metaplastic lashes)
- transformation from normal meibomian glands to hair follicles (pilosebaceous units)
- related to conjunctival scarring
- e.g. chemical burns, ocular pemphigoid, Stevens-Johnsons Syndrome
Treatment for distichiasis (3)
- surgical excision
- division into anterior and posterior lamellae
- cryotherapy to posterior lamella
- reapposition of lamellae
What is madarosis
Loss of eyelashes/eyebrows partial or complete
Cause of madarosis (6)
- local disease
- systemic disorders
- eyelash removal
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