Ординатура / Офтальмология / Английские материалы / Oxford American Handbook of Ophthalmology_Tsai, Denniston, Murray_2011

146 CHAPTER 6 Conjunctiva

Allergic conjunctivitis

Seasonal and perennial allergic rhinoconjunctivitis

These extremely common ocular disorders arise from type I hypersensitivity reactions to airborne allergens. These may be seasonal (grass, tree, weed pollens, ragweed) or perennial (animal dander, house dust mite).

Clinical features

•Itching, watery discharge; history of atopy

•Chemosis, lid edema, papillae, mild diffuse injection

Investigation

Consider conjunctival swabs (microbiology), skin prick testing, serum IgE, and radioallergosorbent test (RAST)

Treatment

•Identify and eliminate allergen where possible (e.g., change bedding, reduce pet contact, introduce air conditioning).

•If mild: artificial tears (dilutes allergen).

•If moderate: mast cell stabilizer (e.g., sodium cromoglycate 2% 4x/day, lodoxamide 0.1% 4x/day) or topical antihistamine (azelastine 0.05% 2–4x/day for 6 weeks maximum, levocabastine 0.05% 2–4x/day), and oral antihistamine (e.g., chlorphenamine 4 mg 3–6x/day).

•If case is severe, include a short course of an additional mild topical steroid (e.g., fluoromethalone 0.1% 4x/day for 1 week).

Vernal keratoconjunctivitis (VKC)

This is an uncommon but serious condition of children and young adults (onset age 5–15 years; duration 5–10 years). Before puberty, it is more common in males but subsequently shows no gender bias.

Although its incidence is decreasing among the white population, it is increasing in Asians. Caucasians more commonly exhibit the tarsal/palpebral form, whereas the limbal form is more common in darker-skinned races; however, a mixed picture is often seen. It is more common in warm climates and is usually seasonal (spring to summer).

Over 80% of patients have an atopic history. Although there is type I hypersensitivity involvement, there is also a cell-mediated role with a predominantly Th2 cell type.

Clinical features

•Itching, thick mucous discharge; typically young male, presenting in spring with history of atopy.

•Tarsal signs: flat-topped giant (“cobblestone”) papillae on superior tarsus.

•Limbal signs: limbal papillae, white Trantas dots (eosinophil aggregates).

•Keratitis: superior punctate epithelial erosions, vernal ulcer with adherent mucus plaque (may result in subepithelial scar),

pseudogerontoxon (corneal lesion resembling segment of arcus senilis).

ALLERGIC CONJUNCTIVITIS 147

Treatment

•Topical: mast cell stabilizer (e.g., sodium cromoglycate 2% g 4x/day), 9 topical steroid ± cyclosporine (either 2% drops or 0.2% oinment 3–4x/ day); consider mucolytic (e.g., acetylcysteine 5% 4x/day).

•Acute exacerbations may require intensive treatment with topical steroids (e.g., dexamethasone 0.1% PF hourly) but then titrate down to the minimum potency and frequency required to control exacerbations (e.g., fluoromethalone 0.1% 1–2x/day). Cyclosporine may be used as an adjunct with a steroid-sparing role.

•Systemic: consider an antiviral (e.g., acyclovir 200 mg 4x/day) if using immunosuppressants since these patients are vulnerable to herpes simplex keratitis.

•Surgical: consider debridement or superficial lamellar keratectomy to remove plaques.

Atopic keratoconjunctivitis

This is a rare but serious condition of adults (onset 25–30 years). Patients are usually atopic, commonly with eczema of the lids and staphylococcal lid disease. Control of lid disease is an important aspect of treatment.

This is a mixed type I and IV hypersensitivity response, but with a higher Th1-cell type component than that in vernal disease.

Clinical features

•Itching, redness; photophobia ± blurred vision (if keratitis); history of atopy.

•Lid eczema, staphylococcal lid disease (anterior blepharitis), small tightly packed papillae, otherwise featureless tarsal conjunctiva (due to inflammation); chemosis + limbal hyperemia (acute exacerbations); may cicatrize (chronic) with forniceal shortening.

•Keratitis: inferior punctate epithelial erosions, shield ulcers, pannus, corneal vascularization, herpes simplex, or microbial keratitis.

•Associations: keratoconus, cataract.

Treatment

•Topical: treat as for VKC, including ocular lubricants + mast cell stabilizer (usually less effective than in VKC) ± topical steroid (e.g., initially dexamethasone 0.1% PF hourly) ± cyclosporine (2% drops or 0.2% ointment 3–4x/day).

•Oral: consider antihistamines (they may help with itching) and corticosteroids (for severe acute exacerbations). If using immunosuppressants, consider an antiviral (e.g., acyclovir 200 mg 4x/day), since these patients are vulnerable to herpes simplex keratitis.

•Surgical: consider debridement or superficial lamellar keratectomy to remove plaques.

•For lid disease: consider topical (e.g., erythromycin ointment 4x/day) and oral (e.g., doxycycline 100 mg 1x/day 3 months) antibiotics.

•For secondary infective keratitis, give topical antivirals and antibiotics.

148 CHAPTER 6 Conjunctiva

Cicatricial conjunctivitis

In this potentially blinding condition, conjunctival inflammation with scarring leads to the loss of conjunctival function (such as goblet cells) and architecture. Onset may be insidious, delaying diagnosis. Although there are many causes, cicatrization has broadly similar ocular features, and similar treatment modalities may be considered.

Primary

Ocular mucous membrane pemphigoid (OMMP)

Mucous membrane pemphigoid is more common in women, usually >60 years of age but may occur in adolescents. It is thought to be a type II hypersensitivity reaction with linear deposition of immunoglobulin (Ig) and complement at the basement membrane of mucosal surfaces, leading to loss of adhesion and bulla formation and subsequent cicatrization.

Oral mucosa and conjunctiva are most commonly affected, although skin and other mucous membranes may be involved. Ocular mucous membrane pemphigoid (OMMP) was formerly known as ocular cicatricial pemphigoid (OCP).

Clinical features

•Irritation.

•Chronic papillary conjunctivitis, subconjunctival vesicles lulcerate, progressive subconjunctival fibrosis and cicatrization (loss of plica semilunaris and fornices, formation of symblepharon/ankyloblepharon), dry eye signs, trichiasis, secondary microbial keratitis, corneal neovascularization, corneal melt, perforation.

Treatment

•Topical: tear substitutes, corticosteroids and antibiotics (preservative-free).

•Systemic immunosuppression (for acute phase of disease): dapsone if mild or moderate; corticosteroids, methotrexate, azathioprine or

cyclophosphamide if severe (consult with a rheumatologist; all patients need monitoring). Systemic immunosuppression is generally required for >1 year.

•Consider silicone contact lenses and surgery (for correction of lid and lash position; punctal occlusion or tarsorrhaphy to upper lid; botulinum toxin is of limited use given the mechanical restriction; corneal transplant or surface reconstruction procedures; keratoprosthesis).

Erythema muliforme, Stevens–Johnson syndrome, and toxic epidermal necrolysis (TEN, Lyell disease)

These are acute vasculitides of the mucous membranes and skin that are associated with drug hypersensitivity (sulfonamides, anticonvulsants, allopurinol) or infections (e.g., mycoplasma, HSV). They are thought to result from a type III hypersensitivity response and may represent different variants of the same disease.

CICATRICIAL CONJUNCTIVITIS 149

Clinical features

•Acute fever/malaise and skin rash (e.g., target lesions or bullae) and hemorrhagic inflammation of 2 mucous membranes.

•Papillary or pseudomembranous conjunctivitis lcicatrization (as for OMMP but is classically nonprogressive once acute illness subsides).

Other bullous diseases in which cicatricial conjunctivitis is common include linear IgA disease (linear IgA at the dermoepidermal junction) and epidermolysis bullosa.

Secondary

Injury

Thermal, radiation, chemical (especially alkali), and surgical injuries may all cause cicatrization.

Anterior blepharitis (staphylococcal)

Limited cicatrization and keratinization of the lid margin with reduced tear film quality may cause chronic irritation.

Infective conjunctivitis

Cicatrization is most common with Chlamydia trachomatis, but may also occur after membranous and pseudomembranous conjunctivitis.

Drugs

Reactions may vary from mild irritation to drug-induced cicatricial conjunctivitis (DICC), which is clinically indistinguishable from OMMP. Drugs implicated may be systemic (practolol, penicillamine) and topical (propine, pilocarpine, timolol, idoxuridine, gentamicin (particularly 1.5%), guanethidine).

Inherited

Consider ectodermal dysplasia if there are associated abnormalities of hair and teeth.

Systemic

Consider rosacea, Sjögren syndrome, and graft-versus-host disease (GVHD). GVHD occurs in some bone marrow transplant patients where the donor’s leukocytes attack the immunosuppressed recipient. In the acute response, there is toxic epidermal necrolysis, which may include a pseudomembranous conjunctivitis. In chronic GVHD, there are scleroder- ma-like changes of the skin and Sjögren-like changes of the glands to cause keratoconjunctivitis sicca.

Neoplastic

Unilateral cicatrizing conjunctivitis may be due to sebaceous cell carcinoma, conjunctival intraepithelial neoplasia (CIN), or squamous cell carcinoma.

150 CHAPTER 6 Conjunctiva

Keratoconjunctivitis sicca

Although patients report dry eyes commonly, most often they are describing mild tear film instability associated with blepharitis. While some symptomatic relief will be obtained from artificial tears, in these cases the blepharitis itself should be the focus of treatment. However, true keratoconjunctivitis sicca may be severe and very painful and threaten vision.

Keratoconjunctivitis sicca

Clinical features

•Burning (may be very painful) ± blurred vision (due to corneal involvement).

•Mucus strands; small or absent concave tear meniscus; punctate epitheliopathy; filaments; mucus plaques; tear film breakup time

<10 sec; rose bengal and/or lissamine green staining pattern; Schirmer test <5 mm over 5 min (without topical anesthetic).

Treatment

Artificial tears (Table 6.4)

•Consider viscosity: low-viscosity drops require frequent administration (sometimes more than hourly) but have minimal effect on vision; more viscous gels will transiently blur the vision but are longer lasting and may be effective when used only 4–6x/day. Highly viscous paraffinbased ointments significantly blur vision and may only be suitable for night-time use.

•Consider preservative-free preparations to reduce risk of epithelial toxicity if frequent administration is required.

•Consider physiological tear substitutes: hyaluronic acid (HA) is a natural component of tears. It is now becoming commercially available for topical application. These preparations are classified as devices rather than as medications. It improves the symptoms of dry eye and appears to have a protective effect on the epithelium. In extreme cases, autologous serum may be used.

Table 6.4 Artificial tears and lubricants

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•Treat blepharitis: lid hygiene ± oral antibiotic (e.g., doxycycline 100 mg 1x/day 3 months).

•Treat active inflammation: consider topical or systemic corticosteroids; if responsive, these patients may benefit from topical cyclosporine (e.g., Restasis).

•Increase secretion: pilocarpine hydrochloride 5 mg 1–4x/day (increase slowly from 5 mg/day to try to reduce anticholinergic side effects). Pilocarpine is approved for dry mouth and dry eyes in Sjögren syndrome but is only effective if there is some residual lacrimal gland function.

•Mucolytic (if filaments, mucus plaques): acetylcysteine 5% 4x/day (warn that it stings).

•Environmental—lower room temperature, moist chamber goggles, room humidifier (limited success).

•Punctal occlusion—temporary or permanent.

Causes of dry eye

Table 6.5 Causes of dry eyes

152 CHAPTER 6 Conjunctiva

Miscellaneous conjunctivitis and conjunctival degenerations

Toxic conjunctivitis

Topical medication (e.g., aminoglycosides, antivirals, glaucoma treatments, preservatives, and contact lens solutions) may result in an inferior papillary reaction. With chronic usage, topical medication (e.g., glaucoma treatments, antibiotics, and antivirals) may cause a follicular reaction and conjunctival cicatrization. Inferior punctate epitheliopathy may be seen.

Treatment is to discontinue the offending agent and consider a preserv- ative-free ocular lubricant (e.g., Celluvisc).

Parinaud’s oculoglandular syndrome

This is a rare unilateral conjunctivitis with granulomatous nodules (+ follicles) on the palpebral conjunctiva, ipsilateral lymphadenopathy (preauricular/submandibular), and systemic upset (malaise, fever). It is most commonly due to cat-scratch disease (Bartonella henselae), but also consider tularemia, mycobacteria (e.g., tuberculosis), sarcoid, syphilis, lymphoproliferative disorders, infectious mononucleosis, or fungi.

Investigations will be dictated by history but consider getting conjunctival biopsy, conjunctival swabs, full blood count (FBC), VDRL, chest X-ray, Mantoux testing, and serology (for cat-scratch disease and tularemia).

Ligneous conjunctivitis

This is a rare idiopathic chronic conjunctivitis of children (especially girls) that is characterized by recurrent pseudomembranes or membranes of the “wood-like” tarsal conjunctiva and often of other mucous membranes (e.g., oropharynx, trachea). Histologically, these comprise fibrin, albumin, IgG, and T and B cells. Treat with topical cyclosporine.

Pinguecula

A yellow-white patch of interpalpebral bulbar conjunctiva is located just nasal or temporal to the limbus. It represents elastotic degeneration of collagen. Reassurance and occasionally ocular lubrication are usually all that is required.

Pterygium

This occurs in patients exposed to dry climates and high ultraviolet (UV) light. It usually arises from the nasal limbus and grows slowly across the cornea. Histologically, it is akin to pinguecula with elastotic degeneration of collagen, but with additional destruction of Bowman’s layer.

It is adherent to underlying tissue for the whole length; unlike pseudopterygium, which is a fold of conjunctiva, only attached at the base and apex, usually resulting from inflammation of the corneal ulceration with adherence of local conjunctiva.

CONJUNCTIVITIS AND CONJUNCTIVAL DEGENERATIONS 153

Clinical features

•Cosmetic issues, astigmatism; it may encroach on visual axis, with foreign body sensation.

•Triangular pink-white fibrovascular band. Signs of activity include rapid growth, engorged vessels, gray leading edge in the cornea, and punctate epitheliopathy. Signs of stability include an iron line (Stocker line) just anterior to the margin.

Treatment

Reserve the following treatment for progressive, vision-threatening lesions, since recurrence is common and may be aggressive.

Excise with conjunctival autograft; amniotic membrane graft or mitomycin C (MMC) may be used when removing recurrent pterygia. If the visual axis is involved, lamellar keratoplasty may also be required.

Concretions

Seen in the elderly and those with chronic blepharitis, these yellow-white deposits may erode through the palpebral conjunctiva, causing a foreign body sensation. If troublesome, they can be removed with a needle (at the slit lamp under topical anesthetic).

Retention cyst

This very common, thin-walled, fluid-filled conjunctival cyst occasionally causes symptoms if it disturbs the corneal tear film. It can be punctured with a needle (at the slit lamp under topical anesthetic) but may recur, in which case, consider excision.

154 CHAPTER 6 Conjunctiva

Pigmented conjunctival lesions

Benign

Congenital

•Conjunctival epithelial melanosis: often bilateral, flat, and patchy freely moving brown pigmentation, which may be diffuse (usually denser around the limbus and anterior ciliary nerves) or focal, e.g., around an intrascleral nerve (Axenfield loop).

•Conjunctival freckle: common, tiny flat freely moving pigmented area.

•Melanocytoma: rare, black pigmentation, fixed, slowly growing.

Acquired

•Deposits, e.g., mascara in the inferior fornix, adrenochrome on forniceal/palpebral conjunctiva (from chronic adrenaline administration).

Premalignant

Primary acquired melanosis (PAM)

This is rare in African Americans. Histological differentiation is vital, since PAM without atypia is a benign melanocytic proliferation, whereas PAM wth atypia has a 50% risk of transformation to melanoma by 5 years.

Clinical

•Unilateral, single or multifocal flat freely moving area of irregular brown pigmentation. Pigmentation and size of the lesion may increase, decrease, or remain constant over time.

•Nodules within PAM suggest malignant transfromation to melanoma.

Treatment

For PAM with atypia use excision + cryotherapy, radiotherapy, and antimetabolite.

Conjunctival nevus

These lesions have a low risk of transformation.

Clinical

These single, defined, freely moving brown-pigmentation cysts occur most commonly at the limbus, followed by the caruncle/plica. They may increase in pigmentation or size at puberty.

Congenital ocular melanocytosis

Oculodermal melanocytosis (nevus of Ota) is the most common variant, followed by the limited dermal and ocular forms. Oculodermal melanocytosis is more common in females and Asians.

Clinical

There is unilateral hyperpigmentation of the face (most commonly in a CN V1/CN V2 distributions; ipsilateral iris hyperchromia, glaucoma [10%] associated with trabecular hyperpigmentation), and melanoma (ocular, dermal, or central nervous system).

PIGMENTED CONJUNCTIVAL LESIONS 155

Malignant

Melanoma

Consider this first when confronted with abnormal conjunctival pigmentation. Although rare, it may be fatal (more common in middle age). Melanoma most commonly arises from atypical primary acquired melanosis, but may arise from a nevus or de novo.

Clinical

•Solitary gray, black, or nonpigmented vascularized nodule fixed to episclera; most commonly at the limbus.

•It may metastasize to draining lymph nodes, lung, liver, or brain.

Prognosis

Five-year mortality is 13%. Poor prognostic factors include a multifocal lesion; caruncle, fornix, or palpebral location; thickness >1 mm; recurrence; and lymphatic or orbital spread.

Treatment

Treatment is with wide local excision + double freeze-thaw cryotherapy to excised margins. Consider adjunctive radiotherapy and antimetabolite if incomplete excision or diffuse. Exenteration may be necessary if the lesion is unresectable.

Key points

•Congenital pigmented lesions that are stable, regular, flat, and asymptomatic (i.e., not bleeding, discharging, inflamed, or affecting vision) are likely to be benign.

•Acquired pigmented lesions that are growing, irregular, elevated, or symptomatic (e.g., bleeding, itchy, painful, inflamed) are more likely to be malignant.

•Specialist consultation and advice should be sought for all potentially malignant and premalignant lesions.