Ординатура / Офтальмология / Английские материалы / Moorfields Manual of Ophthalmology_Jackson_2007

lesions that appear painted on (Fig. 5.18). They stain poorly with fluorescein and lack terminal bulbs. Gentle debridement does not produce a fluorescein-staining ulcer, unlike HSV.

Coarse, nummular, anterior stromal infiltrates may occur subsequent to epithelial disease. Neurotrophic keratitis occurs in ≈50%. Disciform, necrotic, interstitial or peripheral ulcerative keratitis, or sclerokeratitis may occur.

■Anterior chamber: 40% have cells and flare.

■IOP: may be low, normal, or elevated. Marked elevation occurs in 10% (33% if keratouveitis).

■Fundus: optic neuritis, central retinal vein occlusion, central

retinal artery occlusion, necrotizing retinitis (acute retinal necrosis, ARN), thrombophlebitis, localized arteritis ± exudates may occur.

■Cranial nerves: palsies are not uncommon.

Investigations HZO is a clinical diagnosis, but virus may be cultured from vesicles for 3–5 days. Take a careful history to exclude immunocompromise and investigate if suspected.

Acute treatment

■Aciclovir 800 mg 5 times daily p.o. for 7–10 days or famciclovir 500 mg t.d.s. p.o. for 7 days, ideally starting within 72 hours of onset.

■Use skin toilet with or without topical disinfectants to prevent bacterial superinfection.

■For epithelial defects prescribe Oc. chloramphenicol 1% q.d.s.

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Herpes zoster ophthalmicus (Ophthalmic shingles)

■For iritis or moderate to severe disciform disease with intact epithelium use topical steroids commensurate with the severity.

■If HSV is suspected, prescribe Oc. aciclovir 3% five times daily.

■For unstable tear film or exposure keratitis add tear substitutes, e.g. unpreserved hypromellose 0.3% 2-hourly.

■Offer appropriate analgesia and cylcoplegia as required.

■For neurotrophic ulcers consider botulinum toxin protective ptosis or central tarsorrhaphy.

The use of systemic steroids, bandage contact lenses, tissue glue, tarsorrhaphy, and corneal grafts all require senior input, as do immunocompromised patients.

Treatment and follow-up of chronic disease

Corneal anaesthesia recovers fully in 60% in 2–3 months, but 25% develop permanent anaesthesia and neurotrophic keratitis. Disciform immune keratitis responds slowly and may require longterm, low-dose steroids to prevent recurrence. Skin lesions may take weeks to heal, and leave scars.

Post-herpetic neuralgia (neuralgia lasting >6 months or >1 month after the skin heals) may be severe. Consider capsaicin cream 0.025% or 0.075% q.d.s. to affected skin. Burning sensation or erythema occurs in 30%. Capsaicin takes 2–3 weeks for onset of action. Taper frequency when pain relief begins: age <55 years with pain for <3 months, stop 3–5 months after pain relief; age >70 with pain >6 months, continue for 3 years. Restart if pain recurs on cessation. Amitriptyline may help (initially 25–50 mg p.o. nocte, increasing in 25 mg increments every 3–4 days until taking 75–100 mg). If the pain is uncontrolled with these treatments refer to a pain clinic.

Thygeson’s Keratitis

Background An uncommon superficial punctate keratitis of unknown aetiology.

Symptoms Intermittent episodes of irritation/foreign body sensation/pain ≈50%, photophobia ≈50%, blurred vision ≈50%, redness ≈15%, and tearing ≈15%. May rarely be asymptomatic

Signs VA is only mildly affected (6/9 or better in ≈80%), and rarely worse than 6/18. Usually bilateral but may be very asymmetrical. The cornea has discrete, elevated, whitish, crumblike epithelial opacities that stain with fluorescein. Subepithelial ghosts may be present. Opacities are mainly in the pupillary area (Fig. 5.19).

Differential diagnosis Viral keratoconjunctivitis, granular dystrophy, and superficial punctate keratopathy.

Treatment Fluorometholone (FML) 0.1% q.d.s. Unresponsive cases may require a stronger steroid, e.g. dexamethasone 0.1% q.d.s. Bandage contact lenses give symptomatic relief as an alternative to steroids.

Follow-up Review at 1 week; if settling, taper steroid slowly. Control of symptoms may require long-term treatment used as necessary. The clinical course is characterized by exacerbations and remissions with a good visual prognosis (corneal scarring and vascularization do not occur). Monitor for complications of longterm steroid use.

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Corneal dystrophies

Corneal Dystrophies

Predominantly epithelial corneal dystrophies

■Epithelial basement membrane dystrophy (map-dot-fingerprint dystrophy, Cogan’s dystrophy): not a true dystrophy. Abnormal attachment between the epithelium and Bowman’s layer causes recurrent erosions and persistent epithelial defects. These result in subepithelial ‘maps’ (geographic opacities), ‘dots’ (intraepithelial microcysts) and ‘fingerprints’ (subepithelial ridges) (Fig. 5.20). Any condition with repeated epithelial breakdown may produce a similar clinical picture, e.g. chronic epithelial oedema. Symptoms are usually nocturnal or on waking, varying from mild to severe depending on the size of the erosion. Minor trauma can trigger major epithelial breakdown. The severity of clinical symptoms may not parallel slit lamp findings. Fluorescein may show localized epithelial irregularity and epithelial defects. High-magnification examination of the other eye against the red reflex of a dilated pupil may uncover subtle abnormalities when the affected eye is too uncomfortable to examine in detail. Treat as recurrent

corneal erosion syndrome with ointment at night to reduce the frequency of exacerbations, bandage contact lenses to stabilize the epithelium, anterior stromal puncture, or excimer laser phototherapeutic keratectomy (PTK) to create focal debridement just into Bowman layer.

■Meesmann’s dystrophy (juvenile familial epithelial dystrophy): rare, autosomal dominant (AD), bilateral epithelial dystrophy that becomes evident in the first few months of life. Small, clear/grey-white bubble-like epithelial opacities occur in both eyes (Fig. 5.21). Bowman’s layer is unaffected and there are no associated systemic disorders. The central cornea is more affected than the periphery. Initially asymptomatic, as it slowly progresses symptoms of mild ocular irritation, photophobia, and blurred vision may occur. Basement membrane thickening may cause irregular astigmatism. PTK may be effective initially, but the cysts recur.

Corneal dystrophies of Bowman’s layer

■Thiel-Behnke corneal dystrophy (curly fibre corneal dystrophy, corneal dystrophy of Bowman’s layer type II, honeycomb corneal dystrophy, Waardenburg-Jonkers dystrophy): often confused with granular corneal dystrophy (GCD) type III and commonly called Reis-Bückler’s dystrophy. AD inheritance. Painful

corneal erosions start during childhood. Subepithelial corneal opacities with honeycomb pattern are seen centrally with a clear zone at the corneoscleral junction. Recurrent erosions

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Corneal dystrophies

result in subepithelial scarring, irregular astigmatism, and reduced acuity by the second decade. The pathognomonic subepithelial ‘curly’ fibres can only be identified by transmission electron microscopy of biopsy material. PTK may be effective initially, but deep anterior lamellar keratoplasty (DALK) may be required later. Disease may recur in the graft.

■ For ‘true’ Reis-Bückler’s dystrophy see GCD type III below.

Predominantly stromal corneal dystrophies

■Lattice corneal dystrophy (LCD): Characterized by radially orientated, interdigitating or branching filamentous opacities within the corneal stroma (Fig. 5.22). The lattice lines do not coincide with corneal nerves but relate to linear deposits of amyloid.

a.LCD type I: recurrent epithelial erosions are common and usually begin during the first decade of life. Inheritance is AD. Although asymmetrical, both corneas contain foci of amyloid scattered throughout the central corneal stroma and sometimes immediately beneath the epithelium. The peripheral cornea remains relatively transparent. Corneal sensation is diminished. The

endothelium and Descemet’s membrane are spared. LCD I is slowly progressive and usually leads to substantial discomfort and visual impairment before the sixth decade.

Contact lenses and PTK are often helpful. Results of penetrating keratoplasty (PK) are good, but there may be recurrence in the graft.

b.LCD type II (familial amyloid polyneuropathy type IV – Finnish or Meretoja type; Meretoja syndrome): both corneas contain randomly scattered short, fine, glassy lines that are less numerous, more delicate, and more radially orientated than LCD I. The peripheral cornea is chiefly affected and the central cornea is almost spared. Corneal sensitivity is reduced. Epithelial erosions are not a feature. Inheritance is AD with changes from the second decade, but earlier in homozygous patients. Vision is usually not significantly impaired before age 65 years. Grafts are rarely required. The corneal abnormalities are accompanied by a progressive bilateral neuropathy involving the cranial and peripheral nerves, dysarthria, a dry and lax itchy skin with amyloid deposits in the arteries and sclera. A characteristic masklike expression with protruding lips, pendulous ears and blepharochalasis are also features.

■Granular corneal dystrophy (GCD)

a.GCD type I (classic granular dystrophy, Groenouw type I dystrophy): small white sharply demarcated spots that resemble breadcrumbs or snowflakes become apparent in the central cornea beneath Bowman’s layer within the first

decade of life (Fig. 5.23). Inheritance is AD. VA gradually decreases and painful RES is common ( ≈60%). The

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Corneal dystrophies

peripheral 2–3 mm remains clear, as does tissue between the opacities. RES or reduced VA may necessitate excimer PTK. Occasionally DALK or PK is required for deep stromal opacities.

b.GCD type II (GCD with amyloid, Avellino dystrophy, combined lattice–granular dystrophy): less common and severe than GCD I, with onset during the second decade.

Inheritance is AD. Corneal opacities are typically shaped like disc, rings, stars and snowflakes. Painful RES ( ≈15%) occurs especially in women. Contact lenses and PTK are helpful.

c.GCD type III (superficial GCD, ‘true’ Reis-Bückler’s dystrophy, corneal dystrophy of Bowman’s layer type I, geographic corneal dystrophy): usually presents in the second and third decades with bilateral painful RES with AD inheritance. Subepithelial deposits typical of GCD type I progress to anterior corneal scarring with an irregular and roughened surface. Visual loss is more pronounced than Thiel-Behnke dystrophy. Corneal sensitivity is reduced or absent. The deep stroma, Descemet’s membrane, and endothelium are unaffected.

d.GCD type IV (French GCD): phenotype intermediate between GCD I and GCD III. RES begins in early childhood. Inheritance is AD.

■Central crystalline dystrophy (Schnyder’s dystrophy): classically presents early in life with yellow/white ring of needle-shaped, polychromatic crystals in Bowman layer and anterior third of the stroma. The epithelium, Descemet’s membrane, and endothelium are normal. Usually stabilizes after childhood, but gradual corneal opacification may reduce the VA to the point where corneal grafting is required. The dystrophy may recur in the graft. May have associated hypercholesterolaemia, xanthelasmata and genu valgum. Inheritance is AD.

■Macular corneal dystrophy (Groenouw type II dystrophy): autosomal recessive disease that usually begins in the first decade of life. Irregular greyish-white opacities with indistinct edges appear within a hazy corneal stroma. Initially central and superficial, the opacities gradually merge causing progressive clouding of the peripheral and deep stroma. There is primary involvement of Descemet’s membrane with corneal thinning and endothelial guttata (fine wartlike endothelial excrescences). Visual impairment occurs by the fifth decade. Three immunotypes (I, IA, and II) appear similar clinically. PK may become necessary. Rarely there is subclinical recurrence

Posterior corneal dystrophies

■Congenital hereditary endothelial dystrophy (CHED) (hereditary corneal oedema): diffuse, bilateral, symmetrical corneal oedema varies from milky ground glass opacification to mild haze (Fig. 5.24). May have epithelial microbullae and thickening of Descemet’s membrane. There are no guttata, interstitial inflammation, or neovascularization. Check IOP. If the cornea doesn’t clear when raised IOP is normalized, suspect concomitant CHED. Type I (AD) progresses slowly to manifest during the first 2 years of life with photophobia and tearing and no associated ocular or systemic abnormalities. Type II (infantile hereditary endothelial dystrophy) is autosomal recessive and becomes manifest at, or shortly after, birth and is associated with nystagmus.

■Posterior polymorphous corneal dystrophy : Asymmetric, vesicular or annular opacities with surrounding halos are seen at the level of Descemet’s membrane. There is no stromal oedema or vascularization (Fig. 5.25). May have peripheral anterior synechiae. Usually asymptomatic with preserved VA but sometimes progresses slowly from teens. AD inheritance. If grafting is required, disease may recur in graft.

■Fuchs’ endothelial dystrophy (late hereditary endothelial dystrophy): although AD, there is poor penetrance and most

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