195 FUCHS’ CORNEAL DYSTROPHY

a

b

FIGURE 195.1. a) Cornea with Fuchs’ dystrophy stage III corneal edema pre-operatively showing large surface bullae extending onto lower lid and painful red eye. b) Post-operatively at 6 months after deep lamellar endothelial keratoplasty (DLEK) the cornea is clear with no sutures, there are no bullae, and the eye is comfortable.

faster visual rehabilitation than PK and may avoid the short and long term complications.

Painful corneal epithelial bullae with no light perception vision

Cautery, Gunderson flap, and amniotic membrane surgery have all been useful for pain control.

COMMENTS

Fuchs’ dystrophy is a slowly progressive disease which can be observed until the patients symptoms warrant treatment. Every effort should be made to reduce endothelial damage from episodes of intraocular inflammation (iritis) or surgical trauma (cataract surgery). Medical management is best until visual acuity is compromised to the point of interfering with activities essential to daily life. While PK is highly successful, new methods of selective corneal transplantation (DLEK and DSEK) may offer topographic, refractive and tectonic advantages.

Chiou AG-Y, Kaufman SC, Beuerman RW, et al: Confocal microscopy in corneal guttata and Fuchs’ endothelial dystrophy. Br J Ophthalmology 83:185–189, 1999.

Egan CA, Hodge DO, McLaren JW, Bourne WM: Effect of dorzolamide on corneal endothelial function in normal human eyes. Invest Ophthalmol Vis Sci 39:23–29, 1998.

Elder MJ, Stack RR: Globe rupture following penetrating keratoplasty: how often, why, and what can we do to prevent it? Cornea 23:776–780, 2004.

McCartney RK, Wood TO, McLaughin BJ: Moderate Fuchs’ endothelial dystrophy ATPase pump site density. Invest Ophthalmol Vis Sci 30:1560–1564, 1989.

Terry MA, Ousley PJ: Small incision deep lamellar endothelial keratoplasty (DLEK): 6-month results in the first prospective clinical study. Cornea 2005 (in press).

Terry MA: Deep lamellar endothelial keratoplasty (DLEK): pursuing the ideal goals of endothelial replacement. Eye 17:982–988, 2003.

Terry MA, Ousley PJ: Deep lamellar endothelial keratoplasty (DLEK): Visual acvity, astigmatism, and endothelial survival in a large prospective series. Ophthalmology 112:1541–1549, 2005.

Terry MA: Endothelial keratoplasty (EK): History, Current State, and Future Directions. Cornea 25:873–878, 2006 (Editorial).

196 FUCHS’ DELLEN 371.41

(Facets, Fuchs’ Dimples)

F. Hampton Roy, MD, FACS

Little Rock, Arkansas

ETIOLOGY/INCIDENCE

Dellen are paralimbal corneal ulcerations that occur at the base of abnormal conjunctiva or corneal elevations. These ellipsoid depressions, or dells, in the cornea represent a common but not well known phenomenon. Dellen are usually elliptic and saucer shaped with clearly defined edges. Although transient dellen are superficial and purely epithelial, they may last several weeks and become deep. Cicatrization normally follows, often with reduction in corneal thickness (facets).

Abnormal paralimbic conjunctival elevation is associated with:

●Filtering bleb;

●Hematoma;

●Chemosis;

●Conjunctival tumor;

●Rectus muscle surgery;

●Conjunctival autograft;

●Pterygium.

Abnormal corneal elevations can be seen secondary to:

●Localized graft displacement or edema;

●Corneal sutures that are too tight;

●Corneal tumor.

Poor palpebral congruence prevents the lids from normally spreading the tears, which causes a break in the oily film. This break and the resulting desiccation can be aggravated by a trapped air bubble that sometimes bursts when the lids open.

COMMENTS

Dellen are more common than is commonly thought. They are usually benign but occasionally present difficulties. In almost all cases, they heal well with the use of the simple techniques described.

REFERENCES

Fuchs A: Pathological dimples (‘Dellen’) of the cornea. Am J Ophthalmol 12:877–883, 1929.

Insler MS, Tauber S, Packer A: Descemetocele formation in a patient with a postoperative corneal dellen. Cornea 8:129–130, 1989.

Lagoutte F, Gauthier L, Comte P: A fibrin sealant for perforated and preperforated corneal ulcers. Br J Ophthalmol 73:757–761, 1989.

Soong HK, Quigley HA: Dellen associated with filtering blebs. Arch Oph- thalmol;101:385–387, 1983.

197 FUNGAL KERATITIS 111.1

Denis M. O’Day, MD, FACS

Nashville, Tennessee

DIAGNOSIS

Laboratory findings

●Corneal smear: Giemsa, KOH, or Gomori’s methenamine silver stains.

●Culture: Sabouraud dextrose agar, brain-heart infusion broth (no inhibitors).

●Prolonged incubation possibly necessary (weeks).

●Possible contamination of culture (use C streaks to identify inoculum).

Differential diagnosis

●Bacterial and protozoal infections, herpes simplex, or herpes zoster keratitis.

TREATMENT

Yeast infections

Topical 0.15% amphotericin every hour while awake for 48 hours and then every 2 hours (prolonged treatment necessary).

Filamentous fungi

Topical 5% natamycin suspension every hour while awake for 48 hours and then every 2 hours (prolonged treatment necessary).

ETIOLOGY/INCIDENCE

Fungi invade the cornea as a result of a break in the natural host defenses of the eye. This occurs either after trauma or when there is a breakdown of local or general defense mechanisms. Unless the trauma has penetrated the deep layers of the cornea, infection is initially superficial. It progresses slowly to invade the deeper cornea and may involve the adjacent sclera, anterior chamber, and intraocular structures.

Fungal infections are most common in tropical and subtropical climates, where the most frequent isolates are the filamentous fungi Fusarium solani and Aspergillus spp. The majority of cases involve minor trauma, usually with vegetable material as the inciting event. In temperate and colder climates, the infectious agent most often is a yeast. Such infections, however, are rare and are usually associated with reduced immunocompetence, immunosuppression, or severe structural alteration of the cornea and adnexa. In tropical climates, fungal keratitis is a major cause of corneal blindness.

Subconjunctival therapy

No evidence of efficacy.

Systemic therapy

●Yeasts: none indicated.

●Filamentous fungi: some evidence in deep corneal progressive infections for the efficacy of systemic itraconazole or fluconazole (especially for Aspergillus spp. infection).

Surgical

Excisional keratoplasty indicated when disease progresses despite medical treatment.

COMPLICATIONS

●Perforation.

●Anterior endophthalmitis.

●Fungal scleritis.

●Fungal glaucoma.

COMMENTS

The signs of disease progress or regress slowly. Antifungal agents can be toxic to the cornea and may mask response. Steroids have no place in treatment. If a patient is receiving topical steroids at the time of diagnosis, withdraw them slowly.

REFERENCES

Forster RK: Fungal keratitis and conjunctivitis: clinical disease. In: Smolin G, Thoft RD, eds: The cornea: scientific foundations and clinical practice. Boston, Little, Brown, 1994:228–240.

Killingsworth DW, Stern GA, Driebe WT, et al: Results of therapeutic penetrating keratoplasty. Ophthalmology 100:534–541, 1993.

O’Day DM: Fungal keratitis. In: Pepose JS, Holland GN, Wilhelmus KR, eds: Ocular infections and immunity. St Louis, Mosby, 1996:1048–1061.

O’Day DM, Ray WA, Head WS, et al: Influence of corticosteroids on experimentally induced keratomycosis. Arch Ophthalmol 109:1601–1604, 1991.

198 GRANULAR CORNEAL

DYSTROPHY 371.53

Joseph D. Iuorno, MD

Minneapolis MN, USA

Jay H. Krachmer, MD

Minneapolis MN, USA

EITIOLOGY/GENETICS/INCIDENCE

Granular dystrophy is an autosomal dominant inherited dystrophy affecting the corneal stroma. First named Groenouw type I in 1890, the etiology of granular corneal dystrophy (GCD) is still evolving. Recent understandings of molecular genetics have organized GCD into four subtypes. Each subtype has been associated with mutations (Table 198.1) in beta transforming growth factor induced gene in human clone 3 (bIG H3) also known as transforming growth factor beta induced gene (TGFbI). This gene produces an abnormal protein called TGFβI protein (kerato-epithelin) in all four types of granular dystrophy.

Classic GCD type I is characterized by the deposition of small, grayish-white, sharply demarcated opacities mostly in the anterior corneal stroma that can resemble breadcrumb, snowflake or popcorn shapes (Figure 198.1). Characteristic clear

intervening spaces are noted between these corneal deposits. Throughout life, these deposits increase in size and number eventually coalescing to obliterate the clear intervening areas. Initially, these deposits appear in the central anterior stroma, however, over time, they extend posterior and peripherally. Despite their outward expansion, the outlying peripheral corneal stroma remains clear at least 2 mm in from the limbus.

On light microscopy, eosinophilic hyaline deposits appear bright red with Masson’s trichrome stain. Electron microscopy (EM) reveals 100 μm to 500 μm sized rod-shaped extracellular phospholipid structures surrounded by microfibrillar proteins. Proposed etiologic theories suggest an epithelial genesis of GCD based on the prominent epithelial-like whirl pattern noted in corneal transplant graft recurrence.

COURSE/PROGNOSIS

●Onset is early in the first decade of life.

●Visual acuity is minimally affected until the second decade.

FIGURE 198.1. Granular corneal dystrophy. Note the grayish-white, sharply demarcated opacities mostly in the anterior corneal stroma that can resemble breadcrumb, snowflake or popcorn shapes. Characteristic clear intervening spaces are noted between these corneal deposits.