Synopsis of Ophthalmology (eBook)

Chapter 1 The eyelids Publisher Summary This chapter discusses cystic lesions. The cause of external hordeolum (stye) is an acute staphylococcal infection of a lash follicle and its associated gland of Zeis or Moll. This very common lesion presents at any age with an acute onset of a tender swelling, which erupts through the skin. The treatment includes removal of the associated eyelash and application of an antibiotic ointment to the lid margin to prevent spread of the infection; incision of a large abscess may be required. Meibomian gland dysfunction is characterized by the following symptoms: (1) duct obstruction and retention of sebum and (2) secondary chronic lipogranulomatous inflammation. Meibomian cyst (chalazion)—a very common lesion—presents at any age with a gradual onset of a painless swelling in the tarsal plate. Incision through the conjunctiva is the treatment of choice, and injection of triamcinolone into the cyst may also be effective. CYSTIC LESIONS External hordeolum (stye) Cause An acute staphylococcal infection of a lash follicle and its associated gland of Zeis or Moll. Clinical features This very common lesion presents at any age with an acute onset of a tender swelling which points through the skin. Treatment • Removal of the associated eyelash and application of an antibiotic ointment to the lid margin to prevent spread of the infection. •Incision of a large abscess may be required. Meibomian cyst (chalazion) Cause Meibomian gland dysfunction is characterized by: •Duct obstruction and retention of sebum. •Secondary chronic lipogranulomatous inflammation. Clinical features This very common lesion presents at any age with a gradual onset of a painless swelling in the tarsal plate. Treatment •Incision through the conjunctiva is the treatment of choice. •Injection of triamcinolone into the cyst may also be effective. Internal hordeolum Cause An acute staphylococcal infection of a meibomian gland. Clinical features This very common lesion presents in a similar manner to a stye but it is more painful and it may discharge anteriorly or posteriorly. Treatment This is similar to a stye but incision may be necessary if a hard nodule remains. Miscellaneous Cyst of Moll is a tiny translucent retention cyst of a modified sweat gland which contains clear fluid. Cyst of Zeis is a retention cyst of a modified sebaceous gland which is less translucent than a cyst of Moll. Sebaceous cyst is a cyst of an ordinary sebaceous gland which contains cheesy secretions. BENIGN TUMOURS Molluscum contagiosum Cause Virus infection. Clinical features Signs – presents usually in children with small pale umbilicated lid nodules. Complications – ipsilateral chronic follicular conjunctivitis and epithelial keratitis. Treatment Expression or cauterization of the nodule. Miscellaneous Squamous papilloma may be sessile or pedunculated. Verruca vulgaris characterized by filiform warts which may grow in crops. Seborrhoeic keratosis which is greasy brown and friable. Senile keratosis characterized by multiple, flat and scaly lesions which may occasionally undergo malignant change. Xanthelasma are flat, yellow plaques. Keratoacanthoma which starts as a red papule, then turns into a nodule with a crater and regresses within weeks. It may mimic a squamous cell carcinoma. MALIGNANT TUMOURS Basal cell carcinoma Clinical features This is the most common malignant eyelid tumour. It is locally invasive but does not metastasize. The tumour typically presents in old age in one of the following two ways. Noduloulcerative (rodent ulcer) is the most common type. It consists of a well-defined nodule with telangiectatic blood vessels, central ulceration and a ‘pearly’ appearance due to associated hyperkeratosis. Sclerosing (morphea type) is less common. The tumour may be multifocal and because it grows radially it has a flat, ill-defined, scar-like appearance. Treatment • Local excision is the treatment of choice. •Radiotherapy for tumours unsuitable for exision but it should be avoided for the medial canthus because deep infiltration is common. •Cryotherapy for small superficial tumours. •Mohs’ micrographic technique (chemosurgery) for diffusely growing tumours in which the lesion is excised in layers and examined by frozen section. •Exenteration in the rare event of orbital invasion. Squamous cell carcinoma Clinical features This very rare tumour presents in late adult life as an ulcer (most common), a nodule, a ‘papilloma’ or a cutaneous horn. The tumour grows faster than a rodent ulcer and it may metastasize. Treatment Wide excision. Sebaceous gland carcinoma Clinical features This very rare tumour may be multifocal and it may mimic ‘recurrent chalazion’ or ‘severe chronic blepharitis’, hence the frequent delay in diagnosis and poor prognosis. Treatment Wide excision. DISORDERS OF EYELASHES Trichiasis Definition An inward misdirection of normal eyelashes. Causes •Primary (rare). •Secondary to entropion (common). Treatment •Epilation is easy but recurrence occurs within 4–6 weeks. •Electrolysis is tedious and recurrences are common. •Cryotherapy is effective but it may cause skin depigmentation in Black patients. •Argon laser destruction is effective but may need to be repeated. •Protective contact lenses as a temporary measure. Distichiasis Definition An extra row of lashes arising from meibomian gland orifices. Causes •Congenital and familial (very rare). •Secondary to cicatrizing conjunctivitis (see Chapter 4). Treatment •Cryotherapy for the lower eyelid. •Lid splitting and cryotherapy for the upper lid. ENTROPION Classification •Involutional •Cicatricial •Congenital •Acute spastic Involutional entropion Cause A combination of the following age-related changes: •Preseptal orbicularis overrides pretarsal orbicularis (factor a). •Horizontal lid laxity (factor b). •Weakness of lower lid retractors (factor c). Treatment •Cautery through the skin – corrects factor a. •Transverse lid eversion suture – corrects factor a. •Wies procedure (horizontal lid splitting and marginal rotation) –corrects factors a and...