8. Lid, Orbit and Trauma Flashcards
Describe the structure of the skin of the eyelids?
Skin
Epidermis
Skin appendages
a. Sebaceous glands located in the caruncle
b. Meibonian glands are modified sebaceous glands
c. Glands of Zeis, modified sebaceous glands in lash follicles
d. Glands of Moll, modified apocrine sweat glands
What is the function of sebaceous glands?
The function of the sebaceous glands located in the lacrimal caruncle is to secrete tears onto the surface of the conjunctiva.
What is the function of meibonian glands?
Special kind of sebaceous gland at the rim of the eyelids inside the tarsal plate, responsible for the supply of meibum, an oily substance that prevents evaporation of the eye’s tear film. Meibum prevents tear spillage onto the cheek, trapping tears between the oiled edge and the eyeball, and makes the closed lids airtight.
What is the function of the glands of Zeis?
Secretion of oily substance into the middle follicle of eyelash
What is the function of the glands of Moll?
Modified sweat glands, Glands of Moll empty into the adjacent lashes. Glands of Moll and Zeis secrete lipid that adds to the superficial layer of the tear film, retarding evaporation.
What conditions affecting the eyelids have been studied?
Benign & malignant lesions Blepharitis Ptosis Ectropion & entropion Watery eye
What conditions affecting the orbit have been studied?
Orbital Cellulitis
What injuries to the ocular areas have been studied?
Orbital wall fracture
Trauma to the globe
What are the clinical characteristics of benign lid lesions?
Lack of induration & ulceration Uniform colour Limited growth Regular outline Preservation of normal lid margin structure
What is the Tx for benign lid lesions?
Excision (+Biopsy)
Marsupialization, remove the top of the cyst allowing drainage
Ablation with laser or cryotherapy
Chronic, sterile, inflammatory lesion caused by retained sebaceous secretion
Chalazion (Meibomian cyst)
A chalazion secondarily infected referred to as an internal hordeolum
What are the clinical features of malignant eyelid tumours?
Ulceration (>3months, suspect malignancy)
Lack of tenderness
Induration
Irregular borders
Destruction of lid margin architecture (now irregular)
What is the most common human malignancy?
Basal Cell Carcinoma
Who does BCC usually affect?
Most frequently affects elderly with fair skin, inability to tan & exposure to sun light
Where does BCC usually manifest?
90% = Head+Neck
10% of those are on the lower lid (more common than upper)
What are the clinical types of BCC?
a. Nodular BCC
b. Noduloulcerative (rodent ulcer)
c. Sclerosing BCC
What should be ensured following excision of BCC?
Clinically appears much smaller, since continuous under the skin. Margins must be left clear following removal (check in lab) as recurrence may occur.
What are the clinical characteristics of squamous cell carcinoma?
Much less common than BCC
More aggressive than BCC with metastasis to regional LN
Exhibit perineural spread to intracranial cavity
Grow out fast, which is distinct from BCC.
What are the clinical types of SCC?
a. Nodular SCC
b. Ulcerative SCC
c. Cutaneous horn
What is SCC often mistaken for?
Squamous CC can appear similar to benign, which is why we always remove+biopsy suspected benign lesions.
Where does melanoma rarely develop?
On the eyelids…
What are the clinical characteristics of Melanoma of the eyelids?
Potentially lethal
Half of them are non-pigmented
Signs
a. superficial spreading melanoma
b. nodular melanoma
What is Blepharitis?
Common eye condition characterized by often chronic inflammation of the eyelid, generally the part where eyelashes grow. It generally presents when very small oil glands near the base of the eyelashes don’t function properly, resulting in inflamed, irritated, itchy, and reddened eyelids.
What are the clinical characteristics of blepharitis?
Often Staph Aureus
Very common ocular discomfort, grittiness & photophobia
With remission & exacerbation
Usually bilateral & symmetrical
Associated with tear film instability = dry eyes
Mild papillary conjunctivitis & hyperaemia
Stye formation & marginal keratitis
What is the prevelance of blepharitis?
Very Common, esp in elderly
Affects 60% of people above the age of 70