Figure 20-4 Preauricular skin tags in a case of Goldenhar syndrome. (Courtesy of Ken K. Nischal, MD.)
Dermolipoma
A conjunctival lesion, the dermolipoma is usually located near the temporal fornix and is composed of adipose tissue and dense connective tissue. The overlying conjunctival epithelium is normal, and hair follicles are absent. Dermolipomas may be extensive, sometimes involving orbital tissue, the lacrimal gland, and extraocular muscle. Like limbal dermoids, conjunctival dermolipomas are frequently associated with Goldenhar syndrome (see also Chapter 18).
Dermolipomas rarely require excision. If surgery is undertaken, the surgeon should attempt to remove only the portion of the lesion visible within the palpebral fissure, disturbing conjunctiva and the Tenon layer as little as possible to minimize scarring. Cicatrization may occur even with a conservative operative approach.
Abnormalities of Central and Diffuse Corneal Transparency
The mnemonic STUMPED is helpful for remembering the differential diagnosis for congenital corneal opacities (Table 20-1): sclerocornea, tears in Descemet membrane (usually due to forceps trauma or congenital glaucoma), ulcers (infection; see Chapter 28), metabolic (eg, mucopolysaccharidosis), Peters anomaly, edema (eg, congenital hereditary endothelial dystrophy [CHED], posterior polymorphous dystrophy, congenital hereditary stromal dystrophy [CHSD], glaucoma), and dermoid. An alternative classification of corneal opacities is based on whether they are primary or secondary (Table 20-2).
Table 20-1
Table 20-2
Primary causes
Congenital hereditary endothelial dystrophy CHED is an uncommon corneal dystrophy. The cornea is diffusely and uniformly edematous because of a defect of the corneal endothelium and Descemet membrane. The edema involves both the stroma and the epithelium. The appearance of the cornea is similar to that in congenital glaucoma but without increased corneal diameter and elevated intraocular pressure. The hallmark of CHED is increased corneal thickness. CHED type I is the same entity as posterior polymorphous dystrophy (PPMD); both are autosomal dominant on the same locus at pericentromeric chromosome 20 and present in the first or second decade of life without nystagmus. CHED type II presents at birth with nystagmus and is autosomal recessive. Deafness and CHED are seen in Harboyan syndrome.
Posterior polymorphous dystrophy PPMD presents at birth only rarely; it usually presents later. See BCSC Section 8, External Disease and Cornea.
Congenital hereditary stromal dystrophy CHSD is a very rare congenital stationary opacification of the cornea transmitted in an autosomal dominant manner. A flaky or feathery clouding of the stroma, which is of normal thickness, is covered by a smooth, normal epithelium. These features are in contrast with those of CHED, which exhibits a thickened stroma and epithelial edema.
Weiss JS, Møller HU, Lisch W, et al. The IC3D classification of the corneal dystrophies. Cornea. 2008;27(Suppl 2):S1–S83.
Secondary causes
Posterior corneal depression Posterior corneal depression (central posterior keratoconus), a discrete posterior corneal indentation, produces an abnormal red reflex during examination with a retinoscope or direct ophthalmoscope. A highly convex posterior corneal surface is visible with slitlamp examination. Pigment deposits sometimes appear on the border of the posterior defect. The anterior curvature of the cornea is normal. This defect usually causes irregular astigmatism and can result in amblyopia. If refractive correction is not successful, Descemet stripping endothelial keratoplasty (DSEK) can be considered.
Peters anomaly Peters anomaly, also known as iridocorneal or keratolenticular adhesions, is a posterior corneal defect with an overlying stromal opacity, often accompanied by adherent iris strands (Peters anomaly type 1; Fig 20-5A). The size and density of the opacity can range from a mild to dense central leukoma. The strands from the iris to the borders of this defect vary in number and density. In severe cases, the central leukoma may be vascularized and protrude above the level of the cornea. The stromal opacity may decrease with time. Lysis of adherent iris strands has been reported to improve corneal clarity. A more severe variety includes adherence of the lens to the cornea at the site of the central defect (Peters anomaly type 2; Fig 20-5B).
Figure 20-5 A, Corneal opacity secondary to iridocorneal adhesion (Peters anomaly type 1). B, Corneal opacity secondary to keratolenticular adhesion (Peters anomaly type 2). (Courtesy of Ken K. Nischal, MD.)
Peters anomaly can be caused by many different diseases, including genetic conditions (eg, Axenfeld-Rieger syndrome) and nongenetic conditions (eg, congenital rubella). Unilateral cases are usually isolated. Bilateral cases are often associated with systemic disorders and warrant a complete genetic workup. A syndrome called microphthalmia with linear skin defects (MLS) includes microphthalmos, reddish linear skin lesions, and life-threatening cardiac arrhythmias. Peters-plus syndrome is bilateral Peters anomaly associated with congenital brain defects, heart defects, and craniofacial anomalies.
Bhandari R, Ferri S, Whittaker B, Liu M, Lazzaro DR. Peters anomaly: review of the literature. Cornea. 2011;30(8):939–944. Mataftsi A, Islam L, Kelberman D, Sowden JC, Nischal KK. Chromosome abnormalities and the genetics of congenital
corneal opacification. Mol Vis. 2011;17:1624–1640.
Sclerocornea Sclerocornea (total corneal opacification) is a congenital disorder in which the cornea is opaque and resembles the sclera, making the limbus indistinct (Fig 20-6). The central cornea is clearer than the periphery in nearly all cases, in contradistinction to Peters anomaly, in which the periphery is generally clearer. Severe cases show no increased corneal curvature and no apparent scleral sulcus. Sclerocornea is often associated with other ocular or systemic abnormalities. Anterior segment imaging is important for detecting other abnormalities and guiding treatment.
Figure 20-6 Sclerocornea with cornea plana. (Courtesy of Ken K. Nischal, MD.)
Congenital or infantile glaucoma Glaucoma in an infant can cause the cornea to become edematous, cloudy, and enlarged (see Chapter 22).
Traumatic breaks in Descemet membrane Injuries to Descemet membrane may be caused by forceps trauma to the eye during delivery. These are usually vertical and linear, whereas the Haab striae seen in congenital glaucoma are curvilinear. Rupture of Descemet membrane leads to stromal and sometimes epithelial edema. Other signs of trauma are frequently apparent on the child’s head. In most cases, the stromal and epithelial edema regresses, but the edges of the broken Descemet membrane persist and can be seen as ridges protruding slightly from the posterior corneal surface. Amblyopia may result from the corneal opacity. Anisometropic astigmatism induced by the trauma can cause severe amblyopia even if the corneal haze resolves quickly. Follow-up examinations are